k3ylabs/cosoco-image-dataset huggingface dataset:
Package: r-cran-lmertest (3.1-3-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lmerTest
Depends: r-base-core (>= 4.0.2-1build1), r-api-4.0, r-cran-lme4 (>= 1.1-10), r-cran-numderiv, r-cran-mass, r-cran-ggplot2
Description:  GNU R tests in Linear Mixed Effects Models Different kinds of tests for linear mixed effects models as implemented in 'lme4' package are provided. The tests comprise types I - III F tests for fixed effects, LR tests for random effects. The package also provides the calculation of population means for fixed factors with confidence intervals  and corresponding plots. Finally the backward elimination of non-significant effects is implemented.
Package: r-cran-lmtest (0.9.39-1)
Section: universe/math
Homepage: https://cran.r-project.org/package=lmtest
Depends: libc6 (>= 2.29), r-base-core (>= 4.1.2-1), r-api-4.0, r-cran-zoo
Description:  GNU R package for diagnostic checking in linear models This package provides a collection of tests, data sets and examples for diagnostic checking in linear regression models.
Package: r-cran-lobstr (1.1.1-2)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lobstr
Depends: r-base-core (>= 4.1.2-1ubuntu2), r-api-4.0, r-cran-crayon, r-cran-rcpp, r-cran-rlang (>= 0.3.0), libc6 (>= 2.14), libgcc-s1 (>= 3.0), libstdc++6 (>= 5.2)
Description:  visualize R data structures with trees A set of tools for inspecting and understanding R data structures inspired by str(). Includes ast() for visualizing abstract syntax trees, ref() for showing shared references, cst() for showing call stack trees, and obj_size() for computing object sizes.
Package: r-cran-locfit (1.5-9.4-2build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=locfit
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0, r-cran-lattice, libc6 (>= 2.4)
Description:  GNU R local regression, likelihood and density estimation Model formula-based interface to the Locfit library for fitting local regression, likelihood models and density estimation . The package is helpful for running the test suites of several GNU R related packages in Debian.
Package: r-cran-logcondens (2.1.6-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=logcondens
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-ks
Description:  GNU R estimate a log-concave probability density from Iid observations Given independent and identically distributed observations X(1), ..., X(n), compute the maximum likelihood estimator (MLE) of a density as well as a smoothed version of it under the assumption that the density is log-concave, see Rufibach (2007) and Duembgen and Rufibach (2009). The main function of the package is 'logConDens' that allows computation of the log-concave MLE and its smoothed version. In addition, the package provides functions to compute (1) the value of the density and distribution function estimates (MLE and smoothed) at a given point (2) the characterizing functions of the estimator, (3) to sample from the estimated distribution, (5) to compute a two-sample permutation test based on log-concave densities, (6) the ROC curve based on log-concave estimates within cases and controls, including confidence intervals for given values of false positive fractions (7) computation of a confidence interval for the value of the true density at a fixed point. Finally, three datasets that have been used to illustrate log-concave density estimation are made available.
Package: r-cran-logger (0.2.2-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=logger
Depends: r-base-core (>= 4.1.2-1), r-api-4.0
Description:  lightweight, modern and flexible logging utility for GNU R Inspired by the 'futile.logger' R package and 'logging' Python module, this utility provides a flexible and extensible way of formatting and delivering log messages with low overhead.
Package: r-cran-logging (0.10-108-2build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=logging
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0
Description:  GNU R logging package Pure R implementation of the ubiquitous log4j package. It offers hierarchic loggers, multiple handlers per logger, level based filtering, space handling in messages and custom formatting.
Package: r-cran-logspline (2.1.16-1build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=logspline
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0, libblas3 | libblas.so.3, libc6 (>= 2.29)
Description:  GNU R package providing routines for the logspline density estimation The logspline package provides routines for logspline density estimation based on the algorithm from Stone et. al. (1997).
Package: r-cran-loo (2.4.1-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=loo
Depends: r-base-core (>= 4.0.3-1), r-api-4.0, r-cran-checkmate, r-cran-matrixstats (>= 0.52)
Description:  GNU R leave-one-out cross-validation and WAIC for Bayesian models Efficient approximate leave-one-out cross-validation (LOO) for Bayesian models fit using Markov chain Monte Carlo. The approximation uses Pareto smoothed importance sampling (PSIS), a new procedure for regularizing importance weights. As a byproduct of the calculations, it is possible as well to obtain approximate standard errors for estimated predictive errors and for the comparison of predictive errors between models. The package also provides methods for using stacking and other model weighting techniques to average Bayesian predictive distributions.
Package: r-cran-lpsolve (5.6.15-1build1)
Section: universe/math
Homepage: https://cran.r-project.org/package=lpSolve
Depends: libc6 (>= 2.14), r-base-core (>= 4.0.0.20200528-1), r-api-4.0
Description:  GNU R package providing linear program solvers This package provides functions for solving linear, integer and mixed integer programs.
Package: r-cran-lsd (4.1-0-2)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=LSD
Depends: r-base-core (>= 4.0.2-1), r-api-4.0
Description:  Lots of Superior Depictions Create lots of colorful plots in a plethora of variations. Try the LSD demotour().
Package: r-cran-lsei (1.3-0-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lsei
Depends: r-base-core (>= 4.0.2-1build1), r-api-4.0, libc6 (>= 2.14)
Description:  solving problems under equality/inequality constraints The lsei package contains functions that solve least squares linear regression problems under linear equality/inequality constraints. Functions for solving quadratic programming problems are also available, which transform such problems into least squares ones first. It is developed based on the 'Fortran' program of Lawson and Hanson (1974, 1995), which is public domain and available at <http://www.netlib.org/lawson-hanson>.
Package: r-cran-lsmeans (2.30-0-2build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lsmeans
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0, r-cran-emmeans (>= 1.3)
Description:  GNU R package providing least-squares means for various classes of models The r-cran-lsmeans package is a GNU R package to obtain least-squares means for many linear, generalized linear, and mixed models. Additionally it can compute contrasts or linear functions of least- squares means, and comparisons of slopes.
Package: r-cran-lubridate (1.8.0+dfsg-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lubridate
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-generics, r-cran-cpp11 (>= 0.2.7), libc6 (>= 2.34), libgcc-s1 (>= 3.3.1), libstdc++6 (>= 11)
Description:  simplifies dealing with dates in R Functions to work with date-times and timespans: fast and user friendly parsing of date-time data, extraction and updating of components of a date-time (years, months, days, hours, minutes, and seconds), algebraic manipulation on date-time and timespan objects. The 'lubridate' package has a consistent and memorable syntax that makes working with dates easy and fun.
Package: r-cran-luminescence (0.9.18-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=Luminescence
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-bbmle (>= 1.0.24), r-cran-data.table (>= 1.14.0), r-cran-deoptim (>= 2.2-6), r-cran-httr (>= 1.4.2), r-cran-lamw (>= 2.1.0), r-cran-matrixstats (>= 0.61.0), r-cran-minpack.lm (>= 1.2-1), r-cran-mclust (>= 5.4.7), r-cran-plotrix (>= 3.8-1), r-cran-readxl (>= 1.3.1), r-cran-rcpp (>= 1.0.7), r-cran-shape (>= 1.4.6), r-cran-xml (>= 3.99), r-cran-zoo (>= 1.8), r-cran-rcpparmadillo (>= 0.10.7.0.0), libc6 (>= 2.14), libgcc-s1 (>= 3.0), libstdc++6 (>= 5.2)
Description:  GNU R comprehensive luminescence dating data analysis A collection of various R functions for the purpose of Luminescence dating data analysis. This includes, amongst others, data import, export, application of age models, curve deconvolution, sequence analysis and plotting of equivalent dose distributions.
Package: r-cran-lwgeom (0.2-8-1build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=lwgeom
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-rcpp, r-cran-units, r-cran-sf (>= 0.9-3), libc6 (>= 2.29), libgcc-s1 (>= 3.3.1), libgeos-c1v5 (>= 3.5.0), libproj22 (>= 6.0.0), libstdc++6 (>= 11)
Description:  GNU R bindings to selected 'liblwgeom' functions for simple features This GNU R package provides access to selected functions found in 'liblwgeom' library, the light-weight geometry library used by 'PostGIS'.
Package: r-cran-magic (1.6-0-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=magic
Depends: r-base-core (>= 4.1.2-1ubuntu2), r-api-4.0, r-cran-abind
Description:  GNU R create and investigate magic squares A collection of efficient, vectorized algorithms for the creation and investigation of magic squares and hypercubes, including a variety of functions for the manipulation and analysis of arbitrarily dimensioned arrays.  The package includes methods for creating normal magic squares of any order greater than 2.  The ultimate intention is for the package to be a computerized embodiment all magic square knowledge, including direct numerical verification of properties of magic squares (such as recent results on the determinant of odd-ordered semimagic squares).  Some antimagic functionality is included.  The package also serves as a rebuttal to the often-heard comment "I thought R was just for statistics".
Package: r-cran-magick (2.7.3+dfsg-2)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=magick
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-rcpp (>= 0.12.12), r-cran-magrittr, r-cran-curl, libc6 (>= 2.14), libgcc-s1 (>= 3.3.1), libmagick++-6.q16-8, libmagickcore-6.q16-6 (>= 8:6.9.10.2), libstdc++6 (>= 11)
Description:  advanced graphics and image-processing in GNU R Bindings to 'ImageMagick': the most comprehensive open-source image processing library available. Supports many common formats (png, jpeg, tiff, pdf, etc) and manipulations (rotate, scale, crop, trim, flip, blur, etc). All operations are vectorized via the Magick++ STL meaning they operate either on a single frame or a series of frames for working with layers, collages, or animation. In RStudio images are automatically previewed when printed to the console, resulting in an interactive editing environment. The latest version of the package includes a native graphics device for creating in-memory graphics or drawing onto images using pixel coordinates.
Package: r-cran-magrittr (2.0.2-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=magrittr
Depends: r-base-core (>= 4.1.2-1ubuntu2), r-api-4.0, libc6 (>= 2.4)
Description:  GNU R forward-pipe operator Provides a mechanism for chaining commands with a new forward-pipe operator, %>%. This operator will forward a value, or the result of an expression, into the next function call/expression. There is flexible support for the type of right-hand side expressions.
Package: r-cran-maldiquant (1.21-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=MALDIquant
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, libc6 (>= 2.14)
Description:  GNU R package for quantitative analysis of mass spectrometry data MALDIquant provides a complete analysis pipeline for MALDI-TOF and other mass spectrometry data. Distinctive features include baseline subtraction using the SNIP algorithm, peak alignment using warping functions, handling of replicated measurements as well as allowing spectra with different resolutions.
Package: r-cran-maldiquantforeign (0.13-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=MALDIquantForeign
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-maldiquant (>= 1.16.4), r-cran-base64enc, r-cran-digest, r-cran-readbrukerflexdata (>= 1.7), r-cran-readmzxmldata (>= 2.7), r-cran-xml
Description:  GNU R package providing import/export routines for MALDIquant The MALDIquantForeign package reads (tab, csv, Bruker fid, Ciphergen XML, mzXML, mzML, imzML, Analyze 7.5) and writes (tab, csv, msd, mzML) different file formats of mass spectrometry data into/from MALDIquant objects.
Package: r-cran-manipulatewidgets (0.11.1-3)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=manipulateWidgets
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-shiny (>= 1.0.3), r-cran-miniui, r-cran-htmltools, r-cran-htmlwidgets, r-cran-knitr, r-cran-base64enc, r-cran-codetools, r-cran-webshot, r-cran-shinyjs
Description:  GNU R package for more interactivity in interactive charts The package helps to add controls like sliders, pickers, checkboxes, etc. that can be used to modify the input data or the parameters of an interactive chart created with package 'htmlwidgets'.
Package: r-cran-maotai (0.2.4-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=maotai
Depends: r-base-core (>= 4.1.2-1ubuntu2), r-api-4.0, r-cran-matrix, r-cran-rcpp, r-cran-rdpack, r-cran-rspectra, r-cran-rtsne, r-cran-rann, r-cran-cluster, r-cran-labdsv, r-cran-shapes, r-cran-fastcluster, r-cran-dbscan, r-cran-rcpparmadillo, r-cran-rcppdist, libblas3 | libblas.so.3, libc6 (>= 2.29), libgcc-s1 (>= 3.0), libgomp1 (>= 4.9), liblapack3 | liblapack.so.3, libstdc++6 (>= 9)
Description:  Tools for Matrix Algebra, Optimization and Inference Matrix is an universal and sometimes primary object/unit in applied mathematics and statistics. A number of algorithms are provided for selected problems in optimization and statistical inference.
Package: r-cran-mapdata (2.3.0-3)
Section: universe/math
Homepage: https://cran.r-project.org/package=mapdata
Depends: r-base-core (>= 4.0.2-1build1), r-api-4.0, r-cran-maps (>= 2.0-7)
Description:  GNU R support for producing geographic maps (supplemental data) This package provides facilities for easily producing high-resolution maps based on data sets in the GNU R statistical computing environment.  It includes high-resolution map data for the entire world, along with maps of China (including provincial boundaries) and a higher-resolution map of New Zealand and a number of nearby Pacific islands. . The suggested r-cran-mapproj package adds facilities for calculating geographic projections, which are used by mapmakers to compensate for the inaccuracies inherent in projecting a spheroid's surface onto a two-dimensional plane.
Package: r-cran-mapproj (1.2.8-1)
Section: universe/math
Homepage: https://cran.r-project.org/package=mapproj
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-maps (>= 2.3-0), libc6 (>= 2.4)
Description:  GNU R support for cartographic projections of map data This package provides facilities for easily producing cartographic projections of maps based on data sets in the GNU R statistical computing environment.  Projections are used by mapmakers to compensate for the inaccuracies inherent in projecting a spheroid's surface onto a two-dimensional plane.
Package: r-cran-maps (3.4.0-1)
Section: universe/math
Homepage: https://cran.r-project.org/package=maps
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, libc6 (>= 2.4)
Description:  GNU R support for producing geographic maps This package provides facilities for easily producing maps based on data sets in the GNU R statistical computing environment. . The r-cran-maps package includes map data for the United States (including state and county-level maps), New Zealand, and a world map; additional maps (including a higher-resolution world map) are available in the suggested r-cran-mapdata package. . The suggested r-cran-mapproj package adds facilities for calculating geographic projections, which are used by mapmakers to compensate for the inaccuracies inherent in projecting a spheroid's surface onto a two-dimensional plane.
Package: r-cran-maptools (1:1.1-2+dfsg-1)
Section: universe/science
Homepage: https://cran.r-project.org/package=maptools
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-sp (>= 1.0-11), r-cran-foreign (>= 0.8), r-cran-lattice, libc6 (>= 2.14)
Description:  GNU R Tools for reading and handling spatial objects Set of tools for manipulating and reading geographic data, in particular ESRI shapefiles; C code used from shapelib. It includes binary access to GSHHS shoreline files. The package also provides interface wrappers for exchanging spatial objects with packages such as PBSmapping, spatstat, maps, RArcInfo, Stata tmap, WinBUGS, Mondrian, and others.
Package: r-cran-maptree (1.4-7-4build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=maptree
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0, r-cran-cluster, r-cran-rpart
Description:  GNU R mapping, pruning, and graphing tree models This GNU R package provides functions with example data for graphing, pruning, and mapping models from hierarchical clustering, and classification and regression trees.
Package: r-cran-markdown (1.1+dfsg-1build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=markdown
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0, r-cran-xfun, r-cran-mime (>= 0.3), libc6 (>= 2.14)
Description:  GNU R package providing R bindings to the Sundown Markdown rendering library Provides R bindings to the Sundown Markdown rendering library by Vicent Marti e.a., based upon work by Natacha Porté. Markdown is a plain-text     formatting syntax that can be converted to XHTML or other formats. . The R function `markdownToHTML` renders a markdown file to HTML. Options controlling HTML output and supported markdown extensions can be optionally specified. . The package also exports the underlying Sundown C extension API which enables creating and calling custom renderers using the `renderMarkdown` function. . Please note: the rmarkdown package (with leading r) converts R Markdown documents into even more formats, by using pandoc; the CRAN rmarkdown package is a newer and enhanced version of this markdown package.
Package: r-cran-markovchain (0.8.6-1build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=markovchain
Depends: r-base-core (>= 4.1.2-1ubuntu2), r-api-4.0, r-cran-igraph, r-cran-matrix, r-cran-matlab, r-cran-expm, r-cran-rcpp (>= 1.0.2), r-cran-rcppparallel, r-cran-rcpparmadillo (>= 0.9.600.4.0), libblas3 | libblas.so.3, libc6 (>= 2.34), libgcc-s1 (>= 3.0), liblapack3 | liblapack.so.3, libstdc++6 (>= 11), libtbb12 (>= 2021.4.0)
Description:  Easy Handling Discrete Time Markov Chains Functions and S4 methods to create and manage discrete time Markov chains more easily. In addition functions to perform statistical (fitting and drawing random variates) and probabilistic (analysis of their structural proprieties) analysis are provided.
Package: r-cran-mass (7.3-55-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=MASS
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, libc6 (>= 2.4)
Description:  GNU R package of Venables and Ripley's MASS The MASS package provides functions and datasets to support the book 'Modern Applied Statistics with S' (4th edition) by W.N. Venables and B.D. Ripley. The following URL provides more details about the book: URL: http://www.stats.ox.ac.uk/pub/MASS4
Package: r-cran-matching (4.9-11-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=Matching
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, r-cran-mass (>= 7.2-1), libc6 (>= 2.29), libgcc-s1 (>= 3.3.1), libstdc++6 (>= 4.1.1)
Description:  multivariate and propensity score matching with balance optimization Provides functions for multivariate and propensity score matching and for finding optimal balance based on a genetic search algorithm. A variety of univariate and multivariate metrics to determine if balance has been obtained are also provided.
Package: r-cran-matchit (4.3.3-1)
Section: universe/math
Homepage: https://cran.r-project.org/package=MatchIt
Depends: r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-backports (>= 1.1.9), r-cran-rcpp (>= 1.0.7), r-cran-rcppprogress, libc6 (>= 2.14), libgcc-s1 (>= 3.0), libstdc++6 (>= 5.2)
Description:  GNU R package of nonparametric matching methods MatchIt implements the suggestions of Ho, Imai, King, and Stuart (2004) for improving parametric statistical models by preprocessing data with nonparametric matching methods. . MatchIt implements a wide range of sophisticated matching methods, making it possible to greatly reduce the dependence of causal inferences on hard-to-justify, but commonly made, statistical modeling assumptions. The software also easily fits into existing research practices since, after preprocessing with MatchIt, researchers can use whatever parametric model they would have used without MatchIt, but produce inferences with substantially more robustness and less sensitivity to modeling assumptions. MatchIt is an R program, and also works seamlessly within Zelig.
Package: r-cran-mathjaxr (1.4-0-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=mathjaxr
Depends: r-base-core (>= 4.0.4-1build1), r-api-4.0
Description:  GNU R package for 'Mathjax' use in Rd files The package provides 'MathJax' and macros to enable its use within Rd files for rendering equations in the HTML help files.
Package: r-cran-matlab (1.0.2-3build1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=matlab
Depends: r-base-core (>= 4.0.0.20200528-1), r-api-4.0
Description:  MATLAB emulation package Emulate MATLAB code using R
Package: r-cran-matrix (1.4-0-1)
Section: universe/math
Homepage: https://cran.r-project.org/package=Matrix
Depends: libblas3 | libblas.so.3, libc6 (>= 2.29), liblapack3 | liblapack.so.3, r-base-core (>= 4.1.2-1ubuntu1), r-api-4.0, r-cran-lattice
Description:  GNU R package of classes for dense and sparse matrices This CRAN package provides S4 classes and methods for numerical linear algebra using dense or sparse matrices.  The sparse matrix implementation uses code from the LDL sparse matrix package and code from the Metis package of partitioning algorithms.
Package: r-cran-matrixcalc (1.0.5-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=matrixcalc
Depends: r-base-core (>= 4.1.1-2), r-api-4.0
Description:  GNU R functions for matrix calculations -- matrixcalc GNU R package supplying functions to support matrix calculations for probability, econometric and numerical analysis. There are additional functions that are comparable to APL functions which are useful for actuarial models such as pension mathematics.
Package: r-cran-matrixmodels (0.5-0-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=MatrixModels
Depends: r-base-core (>= 4.0.4-1build1), r-api-4.0, r-cran-matrix (>= 1.1-5)
Description:  GNU R package for sparse and dense matrix models The MatrixModels package supports modelling with sparse and dense 'Matrix' matrices, using modular prediction and response module classes.
Package: r-cran-matrixstats (0.61.0-1)
Section: universe/gnu-r
Homepage: https://cran.r-project.org/package=matrixStats
Depends: r-base-core (>= 4.1.1-2), r-api-4.0, libc6 (>= 2.4)
Description:  GNU R methods that apply to rows and columns of a matrix This package provides methods operating on rows and columns of matrices, e.g. col/rowMedians() and col/rowRanks(). There are also some vector-based methods, e.g. anyMissing(), weightedMedians(), and binMeans(). The objective is to have all methods being optimized for speed and memory usage.