Spatial Spectrum Analyzer (SSA): A tool for calculations of spatial distribution of fast Fourier transform spectrum from Object Oriented Micromagnetic Framework output data ?
We present a tool for calculations of Fourier transform spatial distribution taken from magnetization dynamics simulated in Object Oriented Micromagnetic Framework (OOMMF). In OOMMF, as well as in other popular micromagnetic software, output data is organized as magnetization vectors from each simulation cell written down to separate file for each simulation step. Therefore, we use parallel computations to reorganize data in files containing time evolution for each cell. Fast Fourier transform is obtained for selected time period by parallel computations using Matlab. The output is a spatial distribution of the magnitude for the selected frequency in the sample cross-section. It allows for analysis of spin waves localization and therefore helps to understand their origin in investigated sample. Program title: Spatial Spectrum Analyzer (SSA) Catalogue identifier: AEUU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEUU_v1_0.html Program obtainable from: CPC Program Library, Queens University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 6459509 No. of bytes in distributed program, including test data, etc.: 134249057 Distribution format: tar.gz Programming language: Bourne Again SHell (Bash), MATLAB. Computer: Any computer with MATLAB and Bourne Again SHell (Bash) installed. Operating system: Any system with MATLAB and Bourne Again SHell (Bash) installed. Classification: 9. External routines: MATLAB Parallel Computing Toolbox Nature of problem: Numerous dynamic problems of ferromagnetic structures can be investigated by micromagnetic simulations using The Object Oriented MicroMagnetic Framework (OOMMF). However, large amounts of OOMMF output data (typically magnetization configuration files take up several gigabytes for few nanoseconds simulation, depending on the structure size) are difficult to process because of being stored in separate files for each simulation step. In particular, for the Fourier Transform (FT) purposes data from all time steps in a single point is needed, but instead the standard output provided by OOMMF and other popular micromagnetic software contains data from all points in a single time step. What is more, calculations of FT for each simulation cell are usually a demanding task. The total time for sequential analysis can exceed the simulation time itself up to several times. Solution method: The SSA tool reorganizes the simulation data into separate files, which describe a single simulation point each and contain values from all time steps. Afterwards, reorganized files are used to compute Fast Fourier Transform for a chosen frequency. The final result is a spectral density map of a sample at a given frequency. Both parts of the SSA tool make use of parallel computing, greatly decreasing the total time needed to process the data. Additional comments: The distribution file for this program is over 134 Mbytes and therefore is not delivered directly when Download or E-mail is requested. Instead a html file, giving details of how the program can be obtained, is sent. Running time: Strongly depends on sample size and time span. Time for the example described in this paper varies from single hours to few days depending on the number of involved processes.
spatial distribution fast fourier transform object oriented micromagnetic framework micromagnetics local modes