Patent Publication Number: US-2023145853-A1

Title: Method of generating pre-training model, electronic device, and storage medium

Description:
This application claims priority to Chinese Patent Application No. 202111310437.1 filed on Nov. 5, 2021, which is incorporated herein in its entirety by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a field of an artificial intelligence technology, in particular to a field of a computer vision and deep learning technology, and more specifically, to a method of generating a pre-training model, an electronic device, and a storage medium. 
     BACKGROUND 
     The pre-training model may refer to a task-independent model acquired by training a preset model with a large amount of training data. For a downstream task, the pre-training model may be fine-tuned by using a small amount of training data related to the downstream task so as to acquire a model for processing the downstream task. For example, the downstream task may include an image processing task, an audio processing task, or a text processing task, etc. 
     SUMMARY 
     The present disclosure provides a method of generating a pre-training model, an electronic device, and a storage medium. 
     According to one aspect of the present disclosure, a method of generating a pre-training model is provided, including: determining, for each of a plurality of tasks, a performance index set corresponding to a candidate model structure set, wherein the candidate model structure set is determined from a plurality of model structures included in a search space, and the search space is a super-network-based search space; determining, from the candidate model structure set, a target model structure according to a plurality of performance index sets, wherein the target model structure is a model structure meeting a performance index condition, and the plurality of performance index sets correspond to the plurality of tasks respectively; and determining the target model structure as the pre-training model. 
     According to another aspect of the present disclosure, an electronic device is provided, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions, when executed by the at least one processor, cause the at least one processor to perform the method as described above. 
     According to another aspect of the present disclosure, a non-transitory computer-readable storage medium having computer instructions therein is provided, and the computer instructions are configured to cause the computer to perform the method as described above. 
     It should be understood that content described in this section is not intended to identify key or important features in embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will be easily understood through the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are used for better understanding of the solution and do not constitute a limitation to the present disclosure, in which: 
         FIG.  1    schematically shows an exemplary system architecture to which a method and an apparatus of generating a pre-training model may be applied according to embodiments of the present disclosure; 
         FIG.  2    schematically shows a flowchart of a method of generating a pre-training model according to embodiments of the present disclosure; 
         FIG.  3    schematically shows a schematic diagram of a process of generating a pre-training model according to embodiments of the present disclosure; 
         FIG.  4    schematically shows a block diagram of an apparatus of generating a pre-training model according to embodiments of the present disclosure; and 
         FIG.  5    schematically shows a block diagram of an electronic device adapted to implement a method of generating a pre-training model according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, which include various details of embodiments of the present disclosure to facilitate understanding and should be considered as merely exemplary. Therefore, those of ordinary skilled in the art should realize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Likewise, for clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description. 
     The pre-training model may be generated by the following methods. 
     One method is to generate the pre-training model by using an artificial-design-based model structure. That is, the pre-training model may be obtained through the artificially designed model structure. For example, the artificially designed model structure may include a ResNet (Deep Residual Network)-based model structure or a Transformer-based model structure. 
     The other method is to generate the pre-training model by using a model structure obtained based on an automatic deep learning (i.e., AutoDL) search. That is, an AutoDL-based model structure may be obtained by using an ImageNet dataset based on an automatic search method. The pre-training model may be generated by using the AutoDL-based model structure. 
     For one method of the above-mentioned methods, a prediction precision of the pre-training model generated by using the artificial-design-based model structure is not high. For the other method, a data distribution between the ImageNet dataset and a training set used by an actual data processing task is different. Therefore, a prediction precision of the pre-training model generated by using the AutoDL-based model structure is also not high. 
     To this end, embodiments of the present disclosure propose a solution of generating a pre-training model, that is, a target model structure that meets a performance index condition is determined from the candidate model structure set according to a performance index set for each of a plurality of tasks. For the plurality of tasks, a pre-training model that meets the performance index condition may be acquired by automatically searching, which may improve a precision of the pre-training model for a plurality of different tasks. Therefore, a smaller-scale pre-training mode may achieve the same prediction precision as that of a larger-scale pre-training model, and the smaller-scale pre-training model may have a faster training speed. On this basis, if the pre-training model is applied to a chip or other hardware products to perform a text processing task, an image processing task or an audio processing task, etc., a core competitiveness of related products may be improved. 
     In the technical solution of the present disclosure, an acquisition, a storage, a use, a processing, a transmission, a provision, a disclosure, and an application of user personal information and location information involved comply with provisions of relevant laws and regulations, take essential confidentiality measures, and do not violate public order and good custom. 
     In the technical solution of the present disclosure, authorization or consent is obtained from the user before the user&#39;s personal information is obtained or collected. 
       FIG.  1    schematically shows an exemplary system architecture to which a method and an apparatus of generating a pre-training model may be applied according to embodiments of the present disclosure. 
     It should be noted that  FIG.  1    is only an example of a system architecture to which embodiments of the present disclosure may be applied to help those skilled in the art understand the technical content of the present disclosure, but it does not mean that embodiments of the present disclosure may not be applied to other devices, systems, environments or scenarios. For example, in other embodiments, an exemplary system architecture to which the method and the apparatus of generating the pre-training model may be applied may include a terminal device, but the terminal device may implement the method and the apparatus of generating the pre-training model provided in embodiments of the present disclosure without interacting with a server. 
     As shown in  FIG.  1   , a system architecture  100  according to such embodiments may include terminal devices  101 ,  102 ,  103 , network  104 , and server  105 . The network  104  is a medium used to provide a communication link between the terminal devices  101 ,  102 ,  103  and the server  105 . The network  104  may include various connection types, such as wired and/or wireless communication links, etc. 
     The terminal devices  101 ,  102 ,  103  used by a user may interact with the server  105  via the network  104 , so as to receive or send messages, etc. Various communication client applications may be installed on the terminal devices  101 ,  102 ,  103 , such as knowledge reading applications, web browser applications, search applications, instant messaging tools, mailbox clients and/or social platform software, etc. (for example only). 
     The terminal devices  101 ,  102  and  103  may be various electronic devices having display screens and supporting web browsing, including but not limited to smartphones, tablet computers, laptop computers, desktop computers, etc. 
     The server  105  may be a server of various types that provides various services, such as a background management server (for example only) that provides a support for a content browsed by the user using the terminal devices  101 ,  102 ,  103 . The background management server may analyze and process a received user request and other data, and feedback a processing result (e.g., web page, information or data acquired or generated according to the user request) to the terminal devices. 
     The server  105  may be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in a cloud computing service system to solve shortcomings of difficult management and weak business scalability existing in an existing physical host and VPS (Virtual Private Server) service. The server  105  may also be a server of a distributed system, or a server combined with a block-chain. 
     It should be noted that the method of generating the pre-training model provided by embodiments of the present disclosure may generally be performed by the server  105 . Accordingly, the apparatus of generating the pre-training model provided by embodiments of the present disclosure may generally be provided in the server  105 . The method of generating the pre-training model provided by embodiments of the present disclosure may also be performed by a server or a server cluster different from the server  105  and capable of communicating with the terminal devices  101 ,  102 ,  103  and/or the server  105 . Accordingly, the apparatus of generating the pre-training model provided by embodiments of the present disclosure may also be provided in the server or server cluster different from the server  105  and capable of communicating with the terminal devices  101 ,  102 ,  103  and/or the server  105 . 
     Alternatively, the method of generating the pre-training model provided by embodiments of the present disclosure may generally be performed by the terminal device  101 ,  102 , or  103 . Accordingly, the apparatus of generating the pre-training model provided by embodiments of the present disclosure may also be provided in the terminal device  101 ,  102 , or  103 . 
     It should be understood that the number of terminal devices, network and server shown in  FIG.  1    is only schematic. According to the implementation needs, any number of terminal devices, network and server may be provided. 
       FIG.  2    schematically shows a flowchart of a method of generating a pre-training model according to embodiments of the present disclosure. 
     As shown in  FIG.  2   , the method includes operations S 210  to S 230 . 
     In operation S 210 , for each of a plurality of tasks, a performance index set corresponding to a candidate model structure set is determined, wherein the candidate model structure set is determined from a plurality of model structures included in a search space, and the search space is a super-network-based search space. 
     In operation S 220 , a target model structure is determined from the candidate model structure set according to a plurality of performance index sets, wherein the target model structure is a model structure meeting a performance index condition, and the plurality of performance index sets correspond to the plurality of tasks respectively. 
     In operation S 230 , the target model structure is determined as the pre-training model. 
     According to embodiments of the present disclosure, tasks may be classified according to processing data, for example, into an image processing task, a text processing tasks, an audio processing tasks, etc. Each of the plurality tasks may be one of the image processing task, the text processing task, and the audio processing task. However, the present disclosure is not limited to this. The tasks may also be classified according to an application field, for example, into a classification task, a detection task, a segmentation task, a recognition task, a retrieval task, etc. Each of the plurality tasks may be one of the classification task, the detection task, the segmentation task, the recognition task, and the retrieval task. 
     According to embodiments of the present disclosure, an initial search space may refer to a space for providing a model structure. The initial search space may include one or more super-network-based search spaces. The initial search space may be a full amount of search space. 
     According to embodiments of the present disclosure, a plurality of initial search spaces respectively corresponding to the plurality of tasks may be built according to requirements of the plurality of tasks. For example, for each of the plurality of tasks, the initial search space may include a search space corresponding to the task. For example, the initial search space may include at least one of a ResNet (Residual Neural Network)-based search space, a MobileNet-based search space, a Transformer-based search space, etc. corresponding to the task. However, the present disclosure is not limited to this. An initial search space may be built according to requirements of the plurality of tasks. For example, for the plurality of tasks, the initial search space may include a heterogeneous search space. The heterogeneous search space may refer to a search space that includes search spaces of different types. For example, the heterogeneous search space may refer to a search space that includes a plurality of search spaces respectively corresponding to the plurality of tasks. 
     According to embodiments of the present disclosure, the initial search space may include a plurality of model structures. The model structure may be a model structure for performing the above-mentioned one or more tasks. Each model structure may include at least one model substructure and a connection relationship between different model substructures. Each model structure may be a structure acquired by connecting the at least one model substructure based on the connection relationship between the different model substructures. The at least one model substructure included in each model structure may be a structure from at least one operation layer, that is, each model structure may be a structure acquired by connecting the at least one model substructure from the at least one operation layer based on the connection relationship between the different model substructures. For example, the at least one operation layer may include at least one of an input layer, a convolutional layer, a pooling layer, a fully connected layer, a batch normalization layer, a nonlinear layer, etc. The at least one model substructure may include at least one of a convolutional structure (i.e., convolutional kernel), a pooling structure (i.e., pooling kernel), a fully connected structure and a normalization structure. The different model substructures may have the same or different super parameters. The super parameters of the model substructure may include at least one of a size of the model substructure, the number and step size of the model substructure, etc. For example, super parameters of the convolutional structure may include a size of the convolutional structure, the number and convolutional step size of the convolutional structure, etc. The connection relationship may include at least one of addition, channel merging, etc. 
     According to embodiments of the present disclosure, the initial search space may be generated according to a generation strategy of the search space. The generation strategy may be determined based on task generation requirements. For example, the number of expected model substructures, a type of the model substructures, and a connection relationship between the model substructures may be determined according to the task generation requirements. At least one model substructure may be determined according to the number and the type of model substructures. The at least one model substructure is connected based on the connection relationship between the model substructures, so as to acquire at least one model structure. The initial search space is acquired according to the at least one model structure. 
     According to embodiments of the present disclosure, the super-network may be a network including a plurality of model structures determined from the initial search space according to a search strategy. For the plurality of tasks, the plurality of initial search spaces respectively corresponding to the plurality of tasks may be determined, and a plurality of super-networks respectively corresponding to the plurality of initial search spaces may be determined based on the plurality of initial search spaces. For example, there are three tasks, i.e., a task A, a task B and a task C. An initial search space 1 corresponding to the task A, an initial search space 2 corresponding to the task B, and an initial search space 3 corresponding to the task C are built respectively. According to the search strategy, a super-network 1′ corresponding to the task A is determined from the initial search space 1, and a super-network 2′ corresponding to the task B is determined from the initial search space 2, and a super-network 3′ corresponding to the task C is determined from the initial search space 3. 
     According to another embodiment of the present disclosure, for the plurality of tasks, an initial search space including the heterogeneous search space and matching the plurality of tasks may be determined. According to the search strategy, a plurality of super-networks respectively corresponding to the plurality of tasks may be determined from the initial search space including the heterogeneous search space. For example, according to the search strategy, the super-network 1′ corresponding to the task A, the super-network 2′ corresponding to the task B and the super-network 3′ corresponding to the task C are determined from the initial search space including the heterogeneous search space. 
     According to embodiments of the present disclosure, the search strategy may refer to a strategy for determining the super-network from the initial search space. Therefore, it may be considered that the super-network-based search space is a subspace of the initial search space, and thus a composition of the super-network-based search space is the same as that of the initial search space, that is, the super-network-based search space may include a plurality of model structures. Each model structure may include at least one model substructure and a connection relationship between different model substructures. 
     According to embodiments of the present disclosure, the super-network-based search space may be a search space of all model structures included in the super-network. For each of the plurality of super-networks respectively corresponding to the plurality of tasks, the super-network may be trained by using a training set of the task corresponding to the super-network, so as to acquire a trained super-network. After the super-network is trained, model parameters of each model structure included in each of the plurality of trained super-networks may be determined. 
     According to embodiments of the present disclosure, model parameters of each of the plurality of model structures included in the super-network-based search space are determined. There may be a plurality of super-network-based search spaces, and the plurality of super-network-based search spaces may correspond to the plurality of tasks respectively. The super-network-based search space may also be a heterogeneous search space including a plurality of search spaces of different types. 
     According to embodiments of the present disclosure, the candidate model structure set may refer to a set for determining a target model structure. The candidate model set may be determined from a plurality of model structures included in the search space based on a screening strategy. The candidate model structure set may include a plurality of model structures. The model structures included in the candidate model structure set may be called candidate model structures, that is, the candidate model structure set may include a plurality of candidate model structures. The screening strategy may be determined based on screening requirements. For example, the number of the expected model structures and one or more types of the model structures may be determined based on the screening requirements. A plurality of model structures matching the number and the type of the expected model structures may be searched from the search space. According to the plurality of model structures, the candidate model structure set may be acquired. The plurality of model structures matching the number and the type of the expected model structures may be searched from the search space based on a random sampling strategy. The number of candidate model structures included in the candidate model structure set may be greater than or equal to a predetermined number threshold. For example, the predetermined number threshold is one million. 
     According to exemplary embodiments of the present disclosure, for each of a plurality of candidate model sets, a plurality of candidate model structures may be determined from the search space corresponding to the task. For example, for the task A, a plurality of candidate model structures are determined from a search space based on a super-network 1′ corresponding to the task A, so as to form a candidate model structure set corresponding to the task A; for the task B, a plurality of candidate model structures are determined from a search space based on a super-network 2′ corresponding to the task B, so as to form a candidate model structure set corresponding to the task B. 
     Use of a method of determining a candidate model structure set provided by embodiments of the present disclosure may not only achieve an automatic search and improve an intelligence, but also enrich a diversity of the plurality of candidate model structures in the candidate model structure set. 
     According to embodiment of the present disclosure, a plurality of performance index sets correspond to the plurality of tasks respectively. Each of the plurality of performance index sets may include a plurality of performance indexes. The performance index may be used as an index value to evaluate a performance of a model structure for the task. For example, a first performance evaluation set includes a plurality of performance indexes corresponding to the plurality of candidate model structures for the task A. A second performance evaluation set includes a plurality of performance indexes corresponding to the plurality of candidate model structures for the task B. 
     According to embodiments of the present disclosure, a performance of each candidate model structure in an application of the plurality of tasks may be evaluated by using at least one performance index item, and each performance index item has a performance index corresponding to the performance index item. The performance index item may include at least one of a precision, an accuracy, a recall rate, a training speed and a prediction speed. Accordingly, the performance index may include at least one of a precision value, an accuracy value, a recall rate value, a training speed value, a prediction speed value, etc. 
     According to embodiments of the present disclosure, for each of the plurality of tasks, each task has at least one performance index corresponding to each of the plurality of candidate model structures. Thus, each task has a performance index set corresponding to the task on the plurality of candidate model structures. 
     According to embodiments of the present disclosure, the performance index condition may be used as a condition for determining the target model structure from the candidate model structure set. For example, the performance index may include at least one of a precision value, an accuracy value, a recall rate value, a training speed value and a prediction speed value. The performance index condition may include that the target model structure may be a model structure whose precision value meets a precision index condition. However, the present disclosure is not limited to this. The performance index condition may also include that the target model structure may be a model structure whose recall rate value meets a recall index condition. 
     According to embodiments of the present disclosure, after at least one performance index corresponding to each of the plurality of tasks in each candidate model structure is determined, the target model structure may be determined from the plurality of candidate model structures according to the performance index condition and the performance index set corresponding to each of the plurality of tasks. 
     According to embodiments of the present disclosure, the determining the target model structure from the plurality of candidate model structures according to the performance index condition and the performance index set corresponding to each of the plurality of tasks may include: determining, for each of the plurality of tasks, a single performance index of each of the plurality of candidate model structures from the performance index set corresponding to the task, and determining a comprehensive performance index of the candidate model structure for the plurality of tasks based on the single performance index of the candidate model structure. The plurality of candidate model structures in the candidate model structure set may be ranked based on a plurality of comprehensive performance indexes respectively corresponding to the plurality of candidate model structures, so as to acquire a ranking result. The target model structure may be determined from the plurality of candidate model structures according to the ranking result. The ranking may include ranking in an order of the comprehensive performance indexes from small to large or in an order of the comprehensive performance indexes from large to small. Different methods for ranking the comprehensive performance indexes may be configured according to actual business requirements, which will not be limited here. 
     According to embodiments of the present disclosure, the determining a comprehensive performance index of the candidate model structure for the plurality of tasks based on the single performance index of the candidate model structure may include: acquiring the comprehensive performance index by performing a weighted summation on a plurality of single performance indexes corresponding to the candidate model structure. 
     For example, there is one performance index item, such as a precision. There are three tasks, i.e., a task A, a task B and a task C. The candidate model structure set includes three candidate model structures, i.e., a candidate model structure a, a candidate model structure b and a candidate model structure c. The plurality of performance index sets respectively corresponding to the plurality of tasks include a performance index set corresponding to the task A, a performance index set corresponding to the task B, and a performance index set corresponding to the task C. The performance index set corresponding to the task A includes a single performance index A ap  of the candidate model structure a for the task A, a single performance index A bp  of the candidate model structure b for the task A, and a single performance index A cp  of the candidate model structure c for the task A. The performance index set corresponding to the task B includes a single performance index B ap  of the candidate model structure a for the task B, a single performance index B bp  of the candidate model structure b for the task B and a single performance index B cp  of the candidate model structure c for the task B. The performance index set corresponding to the task C includes a single performance index C ap  of the candidate model structure a for the task C, a single performance index C bp  of the candidate model structure b for the task C, and a single performance index C cp  of the candidate model structure c for the task C. 
     For the candidate model structure a, the comprehensive performance index may be determined by a weighted summation based on the single performance index A ap , the single performance index B ap  and the single performance index C ap . 
     For the candidate model structure b, the comprehensive performance index may be determined by a weighted summation based on the single performance index A bp , the single performance index B bp  and the single performance index C bp . 
     For the candidate model structure c, the comprehensive performance index may be determined by a weighted summation based on the single performance index A cp , the single performance index B cp  and the single performance index C cp . 
     In the same way, the ranking may be performed according to the plurality of comprehensive performance indexes respectively corresponding to the plurality of candidate model structures. The candidate model structure c may be determined as the target model structure from the candidate model structure a, the candidate model structure b and the candidate model structure c according to the ranking result. 
     According to embodiments of the present disclosure, a target model structure that meets the performance index condition is determined from the candidate model structure set according to the performance index set corresponding to each of the plurality of tasks, and the candidate model structure set is determined from the super-network-based search space. For the plurality of tasks, a pre-training model that meets the performance index condition may be acquired by automatically searching, which may improve a precision of the pre-training model for a plurality of different tasks. Therefore, a smaller-scale pre-training mode may achieve the same prediction precision as that of a larger-scale pre-training model, and the smaller-scale pre-training model may have a faster training speed. On this basis, if the pre-training model is applied to a chip or other hardware products to perform a text processing task, an image processing task or an audio processing task, etc., a core competitiveness of related products may be improved. 
     According to embodiments of the present disclosure, the above-mentioned method of generating the pre-training model may further include the following operations. 
     For each of the plurality of tasks, a super-network corresponding to the task is trained by using a training set corresponding to the task, so as to acquire a trained super-network corresponding to the task. The search space is acquired based on a plurality of trained super-networks respectively corresponding to the plurality of tasks. 
     According to embodiments of the present disclosure, a plurality of training sets respectively corresponding to the plurality of tasks may be matched, and each training set may be used to train the super-network corresponding to the task. Each training set may include a plurality of training data. The training data may be sample data acquired by the server through the terminal device, sample data acquired by the server from a local storage, or the sample data acquired through the Internet and other channels. 
     According to embodiments of the present disclosure, the super-network may be determined from the initial search space according to the search strategy. The super-network may be trained by using the training set based on a loss function, so as to acquire a trained super-network. For example, an output value of the loss function may be acquired by using the training set based on the loss function. According to the output value of the loss function, model parameters of the super-network may be adjusted until a predetermined condition is met, and the super-network acquired when the predetermined condition is met may be determined as the trained super-network. 
     According to embodiments of the present disclosure, after the plurality of trained super-networks are acquired, the super-network-based search space may be acquired based on the plurality of trained super-networks. The super-network-based search space may be a search space of all model structures included in the plurality of trained super-network. After the trained super-network is acquired by training, model parameters of each model structure included in the trained super-network may be determined. Therefore, the model parameters of each of the plurality of model structures included in the super-network-based search space may also be determined. 
     According to embodiments of the present disclosure, for operation S 210 , the determining, for each of a plurality of tasks, a performance index set corresponding to a candidate model structure set may include the following operation. 
     For each of the plurality of tasks, the candidate model structure set is processed by using a performance predictor corresponding to the task, so as to acquire the performance index set corresponding to the candidate model structure set. 
     According to embodiments of the present disclosure, the performance predictor may be used to predict a performance of the model structure. The performance predictor may be a model that represents a relationship between the model structure and the performance of the model structure. The performance predictor, which represents the relationship between the model structure and the performance of the model structure, may be a model acquired by training a machine learning model or deep learning model. For example, the machine learning model may include a random forest model or ridge regression model. The performance predictor, which represents the relationship between the model structure and the performance of the model structure, may also be a model built by using a statistical model. The statistical model may include a probability distribution model. For example, the probability distribution model may include a Gaussian distribution model or the like. 
     According to embodiments of the present disclosure, a plurality of performance predictors respectively corresponding to the plurality of tasks may be built. For each of the plurality of tasks, the single performance index set corresponding to the candidate model structure set may be determined by using the performance predictor corresponding to the task. 
     According to embodiments of the present disclosure, the above-mentioned method of generating the pre-training model may further include the following operations. 
     An evaluation model structure set is determined from the search space. A plurality of performance predictors respectively corresponding to the plurality of tasks are acquired by using the evaluation model structure set. 
     According to embodiments of the present disclosure, the evaluation model structure set may include a plurality of model structures. The model structures included in the evaluation model structure set may be called evaluation model structures. The evaluation model structure may refer to a representative model structure in the super-network-based search space. Representativeness may indicate that characteristics of a model structure in a search space may be characterized. Model parameters of the evaluation model structure may be determined according to model parameters of a model structure corresponding to the evaluation model structure in the super-network, that is, the model parameters of the evaluation model structure may be consistent with the model parameters of the model structure corresponding to the evaluation model structure in the super-network. The evaluation model structure may be used to participate in building the performance predictor. 
     According to embodiments of the present disclosure, a plurality of model structures may be determined from the search space based on a representative strategy, and the evaluation model structure set may be acquired according to the plurality of model structures. The plurality of performance predictors respectively corresponding to the plurality of tasks may be acquired by using the evaluation model structure set based on a plurality of evaluation sets respectively corresponding to the plurality of tasks. Each of the plurality of evaluation sets may include a plurality of training samples. 
     According to embodiments of the present disclosure, the acquiring the plurality of performance predictors respectively corresponding to the plurality of tasks by using the evaluation model structure set based on a plurality of evaluation sets respectively corresponding to the plurality of tasks may include: processing, for each of the plurality of tasks, an evaluation set corresponding to the task by using the evaluation model structure set, so as to acquire a performance index set corresponding to the evaluation model structure set; acquiring, for each of the plurality of tasks, the performance predictor corresponding to the task by using the evaluation model structure set, the performance index set corresponding to the evaluation model structure set and a predetermined model. 
     According to embodiments of the present disclosure, acquiring, for each of the plurality of tasks, the performance predictor corresponding to the task by using the evaluation model structure set, the performance index set corresponding to the evaluation model structure set and a predetermined model may include: updating, for each of the plurality of tasks, super parameters of an initial probability model by a prediction method based on the performance index set corresponding to the evaluation model structure set, so as to acquire a prediction value of the super parameters. The performance predictor may be determined based on the prediction value of the super parameters. The initial probability model may be a probability distribution model acquired by initializing a probability distribution model corresponding to the initial search space. 
     According to embodiments of the present disclosure, the acquiring, for each of the plurality of tasks, the performance predictor by using the evaluation model structure set, the performance index set corresponding to the evaluation model structure set and a predetermined model may include: training the machine learning model or the deep learning model by using the evaluation model structure set and the performance index set corresponding to the evaluation model structure set, so as to acquire the performance predictor. 
     According to embodiments of the present disclosure, the acquiring the performance predictor by using the evaluation model structure set may include at least one of: processing an evaluation set by using the evaluation model structure set, so as to acquire a precision evaluation value set corresponding to the evaluation model structure set; and acquiring a precision predictor by using the evaluation model structure set and a precision index set corresponding to the evaluation model structure set. 
     According to embodiments of the present disclosure, the precision predictor may be used to predict a precision value of the model structure. 
     According to embodiments of the present disclosure, the above-mentioned method of generating the pre-training model may further include the following operation. 
     An evaluation model code set corresponding to the evaluation model structure set is determined. 
     According to embodiments of the present disclosure, the acquiring, for each of the plurality of tasks, the performance predictor corresponding to the task by using the evaluation model structure set and the performance index set corresponding to the evaluation model structure set may include the following operation. 
     For each of the plurality of tasks, the performance predictor corresponding to the task is acquired by using the evaluation model code set corresponding to the evaluation model structure set and the performance index set corresponding to the evaluation model structure set. 
     According to embodiments of the present disclosure, the model structure may be characterized by model codes, that is, each evaluation model structure in the evaluation model structure set may be processed by using a code generator, so as to acquire evaluation model codes corresponding to each evaluation model structure. 
     According to embodiments of the present disclosure, the determining an evaluation model structure set from the search space may include the following operations. 
     An information entropy corresponding to each of the plurality of model structures included in the search space is determined. The evaluation model structure set is determined from the search space according to the information entropy corresponding to each of the plurality of model structures included in the search space. 
     According to embodiments of the present disclosure, the information entropy may be used to characterize a measurement of an amount of information. The evaluation model structure set may be determined from the plurality of model structures included in the search space by using the information entropy of the model structure. 
     According to embodiments of the present disclosure, model codes of each of the plurality of model structures included in the search space may be determined. A covariance matrix is determined according to super parameters of a probability model and the model codes of each model structure. The information entropy of each model structure is determined according to the covariance matrix. The above-mentioned method of determining the information entropy of the model structure is only an exemplary embodiment, but the present disclosure is not limited to this. The method may also include determination methods known in the art, as long as a determination of the information entropy of the model structure may be achieved. 
     According to embodiments of the present disclosure, the determining the evaluation model structure set from the search space according to the information entropy corresponding to each of the plurality of model structures included in the search space may include: ranking for the information entropy corresponding to each of the plurality of model structures included in the search space. The evaluation model structure set is determined from the search space according to a ranking result. The ranking may include ranking in an order of the information entropy from large to small or ranking in an order of the information entropy from small to large. For example, each of the plurality of model structures included in the search space may be ranked according to the order of information from large to small, and a predetermined number of model structures ranked top in the ranking result may be determined as the evaluation model structure set. Alternatively, the evaluation model structure set may be determined from the plurality of model structures included in the search space according to an information entropy threshold and the information entropy corresponding to each of the plurality of model structures included in the search space. For example, for each of the plurality of model structures included in the search space, when it is determined that the information entropy of the model structure is greater than or equal to the information entropy threshold, the model structure may be determined as the evaluation model structure. 
     According to embodiments of the present disclosure, the determining an evaluation model structure set from the search space may include the following operations. 
     At least one cluster center corresponding to the search space is determined according to the plurality of model structures included in the search space. The evaluation model structure set is determined from the search space according to the at least one cluster center corresponding to the search space. 
     According to embodiments of the present disclosure, the model structure in the plurality of model structures included in the search space may be processed by using a clustering algorithm, so as to acquire the at least one cluster center corresponding to the search space. The clustering algorithm may include a K-means clustering algorithm, a K-center clustering algorithm, a CLARA (Clustering LARge Application) algorithm or a fuzzy C-means algorithm. 
     According to embodiments of the present disclosure, each of the at least one cluster center corresponding to the search space may be determined as the evaluation model structure. 
     The above is only an exemplary embodiment, but the present disclosure is not limited to this. The method of generating the pre-training model may further include other methods of generating a pre-training model known in the art, as long as a prediction precision of the pre-training model may be improved. 
     With reference to  FIG.  3   , the method shown in  FIG.  2    will be further described below in combination with specific embodiments. 
       FIG.  3    schematically shows a schematic diagram of a process of generating a pre-training model according to embodiments of the present disclosure. 
     As shown in  FIG.  3   , in  300 , an evaluation model structure set  302  is determined from a super-network-based search space  301 . For each of the plurality of tasks, an evaluation set  303  corresponding to the task is processed by using the evaluation model structure  302 , so as to acquire a performance index set  304  corresponding to the task in the evaluation model structure set  302 . 
     For each of the plurality of tasks, a performance predictor  306  corresponding to the task is acquired by using the evaluation model structure set  302 , the performance index set  304  corresponding to the task in the evaluation model structure set  302 , and a predetermined model  305 . 
     For each of the plurality of tasks, a candidate model structure set  307  corresponding to the task is determined from the super-network-based search space  301 . 
     For each of the plurality of tasks, the candidate model structure set  307  corresponding to the task is processed by using the performance predictor  306  corresponding to the task, so as to acquire a performance index set  308  corresponding to the task. 
     A target model structure  309  is determined from the candidate model structure set  307  according to a plurality of performance index sets  308  respectively corresponding to the plurality of tasks. The target model structure  309  is used as a pre-training model  310 . 
       FIG.  4    schematically shows a block diagram of an apparatus of generating a pre-training model according to embodiments of the present disclosure. 
     As shown in  FIG.  4   , an apparatus  400  of generating a pre-training model may include a first determination module  410 , a second determination module  420 , and a third determination module  430 . 
     The first determination module  410  is used to determine, for each of a plurality of tasks, a performance index set corresponding to a candidate model structure set, wherein the candidate model structure set is determined from a plurality of model structures included in a search space, and the search space is a super-network-based search space. 
     The second determination module  420  is used to determine, from the candidate model structure set, a target model structure according to a plurality of performance index sets, wherein the target model structure is a model structure meeting a performance index condition, and the plurality of performance index sets correspond to the plurality of tasks respectively. 
     The third determination module  430  is used to determine the target model structure as the pre-training model. 
     According to embodiments of the present disclosure, the above-mentioned apparatus  400  of generating the pre-training model may further include a first acquisition module and a second acquisition module. 
     The first acquisition module is used to train, for each of the plurality of tasks, a super-network corresponding to the task by using a training set corresponding to the task, so as to acquire a trained super-network corresponding to the task. 
     The second acquisition module is used to acquire the search space based on a plurality of trained super-networks respectively corresponding to the plurality of tasks. 
     According to embodiments of the present disclosure, the first determination module  410  may include a first acquisition sub-module. 
     The first acquisition sub-module is used to process, for each of the plurality of tasks, the candidate model structure set by using a performance predictor corresponding to the task, so as to acquire the performance indicator set corresponding to the candidate model structure set. 
     According to embodiments of the present disclosure, the above-mentioned apparatus  400  of generating the pre-training model may further include a fourth determination module and a third acquisition module. 
     The fourth determination module is used to determine an evaluation model structure set from the search space. 
     The third acquisition module is used to acquire a plurality of performance predictors respectively corresponding to the plurality of tasks by using the evaluation model structure set. 
     According to embodiments of the present disclosure, the third acquisition module may include a second acquisition sub-module and a third acquisition sub-module. 
     The second acquisition sub-module is used to process, for each of the plurality of tasks, an evaluation set corresponding to the task by using the evaluation model structure set, so as to acquire a performance index set corresponding to the evaluation model structure set. 
     The third acquisition sub-module is used to acquire, for each of the plurality of tasks, the performance predictor corresponding to the task by using the evaluation model structure set and the performance index set corresponding to the evaluation model structure set. 
     According to embodiments of the present disclosure, the above-mentioned apparatus  400  of generating the pre-training model may further include a fifth determination module. 
     The fifth determination module is used to determine an evaluation model code set corresponding to the evaluation model structure set. 
     According to embodiments of the present disclosure, the third acquisition sub-module may include a first acquisition unit. 
     The first acquisition unit is used to acquire, for each of the plurality of tasks, the performance predictor corresponding to the task by using the evaluation model code set corresponding to the evaluation model structure set and the performance index set corresponding to the evaluation model structure set. 
     According to embodiments of the present disclosure, the fourth determination module may include a first determination sub-module and a second determination sub-module. 
     The first determination sub-module is used to determine an information entropy corresponding to each of the plurality of model structures included in the search space. 
     The second determination sub-module is used to determine the evaluation model structure set from the search space according to the information entropy corresponding to each of the plurality of model structures included in the search space. 
     According to embodiments of the present disclosure, the fourth determination module may include a third determination sub-module and a fourth determination sub-module. 
     The third determination sub-module is used to determine at least one cluster center corresponding to the search space according to the plurality of model structures included in the search space. 
     The fourth determination sub-module is used to determine, from the search space, the evaluation model structure set according to the at least one cluster center corresponding to the search space. 
     According to embodiments of the present disclosure, each of a plurality of performance indexes included in the performance index set includes at least one of: a precision value, a recall rate value, a training speed value and a prediction speed value. 
     According to embodiments of the present disclosure, the present disclosure further provides an electronic device, a readable storage medium and a computer program product. 
     According to embodiments of the present disclosure, an electronic device is provided, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, and the instructions, when executed by the at least one processor, cause the at least one processor to perform the method as described above. 
     According to embodiments of the present disclosure, a non-transitory computer-readable storage medium having computer instructions therein is provided, and the computer instructions are configured to cause the computer to perform the method as described above. 
     According to embodiments of the present disclosure, a computer program product including a computer program is provided, and the computer program, when executed by a processor, causes the processor to implement the method as described above. 
       FIG.  5    shows a schematic block diagram of an exemplary electronic device  500  that may be used to implement embodiments of the present disclosure. The electronic device is intended to represent various forms of digital computers, such as a laptop computer, a desktop computer, a workstation, a personal digital assistant, a server, a blade server, a mainframe computer, and other suitable computers. The electronic device may further represent various forms of mobile devices, such as a personal digital assistant, a cellular phone, a smart phone, a wearable device, and other similar computing devices. The components as illustrated herein, and connections, relationships, and functions thereof are merely examples, and are not intended to limit the implementation of the present disclosure described and/or required herein. 
     As shown in  FIG.  5   , the electronic device  500  includes a computing unit  501  which may perform various appropriate actions and processes according to a computer program stored in a read only memory (ROM)  502  or a computer program loaded from a storage unit  508  into a random access memory (RAM)  503 . In the RAM  503 , various programs and data necessary for an operation of the electronic device  500  may also be stored. The computing unit  501 , the ROM  502  and the RAM  503  are connected to each other through a bus  504 . An input/output (I/O) interface  505  is also connected to the bus  504 . 
     A plurality of components in the electronic device  500  are connected to the I/O interface  505 , including: an input unit  506 , such as a keyboard, or a mouse; an output unit  507 , such as displays or speakers of various types; a storage unit  508 , such as a disk, or an optical disc; and a communication unit  509 , such as a network card, a modem, or a wireless communication transceiver. The communication unit  509  allows the electronic device  500  to exchange information/data with other devices through a computer network such as Internet and/or various telecommunication networks. 
     The computing unit  501  may be various general-purpose and/or dedicated processing assemblies having processing and computing capabilities. Some examples of the computing units  501  include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (Al) computing chips, various computing units that run machine learning model algorithms, a digital signal processing processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit  501  executes various methods and steps described above, such as the method of generating the pre-training model. For example, in some embodiments, the method of generating the pre-training model may be implemented as a computer software program which is tangibly embodied in a machine-readable medium, such as the storage unit  508 . In some embodiments, the computer program may be partially or entirely loaded and/or installed in the electronic device  500  via the ROM  502  and/or the communication unit  509 . The computer program, when loaded in the RAM  503  and executed by the computing unit  501 , may execute one or more steps in the method of generating the pre-training model described above. Alternatively, in other embodiments, the computing unit  501  may be configured to perform the method of generating the pre-training model by any other suitable means (e.g., by means of firmware). 
     Various embodiments of the systems and technologies described herein may be implemented in a digital electronic circuit system, an integrated circuit system, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a system on chip (SOC), a complex programmable logic device (CPLD), a computer hardware, firmware, software, and/or combinations thereof. These various embodiments may be implemented by one or more computer programs executable and/or interpretable on a programmable system including at least one programmable processor. The programmable processor may be a dedicated or general-purpose programmable processor, which may receive data and instructions from a storage system, at least one input device and at least one output device, and may transmit the data and instructions to the storage system, the at least one input device, and the at least one output device. 
     Program codes for implementing the methods of the present disclosure may be written in one programming language or any combination of more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a dedicated computer or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program codes may be executed entirely on a machine, partially on a machine, partially on a machine and partially on a remote machine as a stand-alone software package or entirely on a remote machine or server. 
     In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in connection with an instruction execution system, an apparatus or a device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or any suitable combination of the above. More specific examples of the machine-readable storage medium may include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read only memory (ROM), an erasable programmable read only memory (EPROM or a flash memory), an optical fiber, a compact disk read only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. 
     In order to provide interaction with the user, the systems and technologies described here may be implemented on a computer including a display device (for example, a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user, and a keyboard and a pointing device (for example, a mouse or a trackball) through which the user may provide the input to the computer. Other types of devices may also be used to provide interaction with the user. For example, a feedback provided to the user may be any form of sensory feedback (for example, visual feedback, auditory feedback, or tactile feedback), and the input from the user may be received in any form (including acoustic input, voice input or tactile input). 
     The systems and technologies described herein may be implemented in a computing system including back-end components (for example, a data server), or a computing system including middleware components (for example, an application server), or a computing system including front-end components (for example, a user computer having a graphical user interface or web browser through which the user may interact with the implementation of the system and technology described herein), or a computing system including any combination of such back-end components, middleware components or front-end components. The components of the system may be connected to each other by digital data communication (for example, a communication network) in any form or through any medium. Examples of the communication network include a local area network (LAN), a wide area network (WAN), and the Internet. 
     A computer system may include a client and a server. The client and the server are generally far away from each other and usually interact through a communication network. The relationship between the client and the server is generated through computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a block-chain. 
     It should be understood that steps of the processes illustrated above may be reordered, added or deleted in various manners. For example, the steps described in the present disclosure may be performed in parallel, sequentially, or in a different order, as long as a desired result of the technical solution of the present disclosure may be achieved. This is not limited in the present disclosure. 
     The above-mentioned specific embodiments do not constitute a limitation on the scope of protection of the present disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions may be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present disclosure shall be contained in the scope of protection of the present disclosure.