Packages — R (Page 4 of 9)
r-learnr 0.9.2 — Interactive tutorials for R
This package provides tools to create interactive tutorials using R Markdown. Use a combination of narrative, figures, videos, exercises, and quizzes to create self-paced tutorials for learning about R and R packages.
r-limma 3.36.1 — Package for linear models for microarray and RNA-seq data
This package can be used for the analysis of gene expression studies, especially the use of linear models for analysing designed experiments and the assessment of differential expression. The analysis methods apply to different technologies, including microarrays, RNA-seq, and quantitative PCR.
r-limsolve 18.104.22.168 — Solving linear inverse models
This package provides functions that:
find the minimum/maximum of a linear or quadratic function,
sample an underdetermined or overdetermined system,
solve a linear system Ax=B for the unknown x.
It includes banded and tridiagonal linear systems. The package calls Fortran functions from LINPACK.
r-lme4 1.1-17 — Linear mixed-effects models using eigen and S4
This package provides fit linear and generalized linear mixed-effects models. The models and their components are represented using S4 classes and methods. The core computational algorithms are implemented using the Eigen C++ library for numerical linear algebra and RcppEigen glue.
r-lmoments 1.2-3 — L-moments and quantile mixtures
This package contains functions to estimate L-moments and trimmed L-moments from the data. It also contains functions to estimate the parameters of the normal polynomial quantile mixture and the Cauchy polynomial quantile mixture from L-moments and trimmed L-moments.
r-lmtest 0.9-36 — Testing linear regression models
This package provides a collection of tests, data sets, and examples for diagnostic checking in linear regression models. Furthermore, some generic tools for inference in parametric models are provided.
r-locfit 1.5-9.1 — Local regression, likelihood and density estimation
This package provides functions used for local regression, likelihood and density estimation.
r-lpsolve 5.6.13 — R interface to Lp_solve to solve linear/integer programs
Lp_solve is software for solving linear, integer and mixed integer programs. This implementation supplies a "wrapper" function in C and some R functions that solve general linear/integer problems, assignment problems, and transportation problems.
r-lubridate 1.7.4 — Make dealing with dates a little easier
This package provides functions to work with date-times and time-spans: 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 time-span objects. The 'lubridate' package has a consistent and memorable syntax that makes working with dates easy and fun.
r-magic 1.5-8 — Create and investigate magic squares
This package provides 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.
r-magrittr 1.5 — A forward-pipe operator for R
Magrittr 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. For more information, see package vignette. To quote Rene Magritte, "Ceci n'est pas un pipe."
r-maldiquant 1.17 — Quantitative analysis of mass spectrometry data
This package provides a complete analysis pipeline for matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) and other two-dimensional mass spectrometry data. In addition to commonly used plotting and processing methods it includes distinctive features, namely baseline subtraction methods such as morphological filters (TopHat) or the statistics-sensitive non-linear iterative peak-clipping algorithm (SNIP), peak alignment using warping functions, handling of replicated measurements as well as allowing spectra with different resolutions.
r-mapproj 1.2.6 — Map projection in R
This package converts latitude/longitude into projected coordinates.
r-maps 3.3.0 — Draw geographical maps
This package provies an R module for display of maps. Projection code and larger maps are in separate packages ('mapproj' and 'mapdata').
r-maptools 0.9-2 — Tools for reading and handling spatial objects
This package provides a set of tools for manipulating and reading geographic data, in particular ESRI Shapefiles. It includes binary access to GSHHG shoreline files. The package also provides interface wrappers for exchanging spatial objects with other R packages.
r-markdown 0.8 — Markdown rendering for R
This package provides R bindings to the Sundown Markdown rendering library (https://github.com/vmg/sundown). Markdown is a plain-text formatting syntax that can be converted to XHTML or other formats.
r-marray 1.58.0 — Exploratory analysis for two-color spotted microarray data
This package contains class definitions for two-color spotted microarray data. It also includes fuctions for data input, diagnostic plots, normalization and quality checking.
r-mass 7.3-50 — Support functions and datasets for Venables and Ripley's MASS
This package provides functions and datasets for the book "Modern Applied Statistics with S" (4th edition, 2002) by Venables and Ripley.
r-matrix 1.2-14 — Sparse and dense matrix classes and methods
This package provides classes and methods for dense and sparse matrices and operations on them using LAPACK and SuiteSparse.
r-matrixmodels 0.4-1 — Modelling with sparse and dense matrices
This package models with sparse and dense matrix matrices, using modular prediction and response module classes.
r-matrixstats 0.53.1 — Methods applying to vectors and matrix rows and columns
This package provides methods operating on rows and columns of matrices, e.g.
rowSds(). There are also some vector-based methods, e.g.
weightedMedians(). All methods have been optimized for speed and memory usage.
r-mclust 5.4 — Gaussian mixture modelling for model-based clustering etc.
This package provides Gaussian finite mixture models fitted via EM algorithm for model-based clustering, classification, and density estimation, including Bayesian regularization, dimension reduction for visualisation, and resampling-based inference.
r-memoise 1.1.0 — Memoise functions for R
This R package allows to cache the results of a function so that when you call it again with the same arguments it returns the pre-computed value.
r-metap 0.9 — Meta-analysis of significance values
The canonical way to perform meta-analysis involves using effect sizes. When they are not available this package provides a number of methods for meta-analysis of significance values including the methods of Edgington, Fisher, Stouffer, Tippett, and Wilkinson; a number of data-sets to replicate published results; and a routine for graphical display.
r-methylkit 1.6.1 — DNA methylation analysis from high-throughput bisulfite sequencing results
MethylKit is an R package for DNA methylation analysis and annotation from high-throughput bisulfite sequencing. The package is designed to deal with sequencing data from Reduced representation bisulfite sequencing (RRBS) and its variants, but also target-capture methods and whole genome bisulfite sequencing. It also has functions to analyze base-pair resolution 5hmC data from experimental protocols such as oxBS-Seq and TAB-Seq.
r-mgcv 1.8-24 — Mixed generalised additive model computation
GAMs, GAMMs and other generalized ridge regression with multiple smoothing parameter estimation by GCV, REML or UBRE/AIC. The library includes a
gam() function, a wide variety of smoothers, JAGS support and distributions beyond the exponential family.
r-mice 3.1.0 — Multivariate imputation by chained equations
Multiple imputation using Fully Conditional Specification (FCS) implemented by the MICE algorithm as described in http://doi.org/10.18637/jss.v045.i03. Each variable has its own imputation model. Built-in imputation models are provided for continuous data (predictive mean matching, normal), binary data (logistic regression), unordered categorical data (polytomous logistic regression) and ordered categorical data (proportional odds). MICE can also impute continuous two-level data (normal model, pan, second-level variables). Passive imputation can be used to maintain consistency between variables. Various diagnostic plots are available to inspect the quality of the imputations.
r-microbenchmark 1.4-4 — Accurate timing functions for R
This package provides infrastructure to accurately measure and compare the execution time of R expressions.
r-mime 0.5 — R package to map filenames to MIME types
This package guesses the MIME type from a filename extension using the data derived from /etc/mime.types in UNIX-type systems.
r-minimal 3.5.0 — Environment for statistical computing and graphics
R is a language and environment for statistical computing and graphics. It provides a variety of statistical techniques, such as linear and nonlinear modeling, classical statistical tests, time-series analysis, classification and clustering. It also provides robust support for producing publication-quality data plots. A large amount of 3rd-party packages are available, greatly increasing its breadth and scope.
r-minqa 1.2.4 — Derivative-free optimization algorithms by quadratic approximation
This package provides a derivative-free optimization by quadratic approximation based on an interface to Fortran implementations by M. J. D. Powell.
r-mitml 0.3-5 — Tools for multiple imputation in multilevel modeling
This package provides tools for multiple imputation of missing data in multilevel modeling. It includes a user-friendly interface to the packages pan and jomo, and several functions for visualization, data management and the analysis of multiply imputed data sets.
r-mixtools 1.1.0 — Tools for analyzing finite mixture models
This package provides a collection of R functions for analyzing finite mixture models.
r-mnormt 1.5-5 — Multivariate normal and "t" distributions
This package provides functions for computing the density and the distribution function of multivariate normal and "t" random variables, and for generating random vectors sampled from these distributions. Probabilities are computed via non-Monte Carlo methods.
r-modelmetrics 1.1.0 — Rapid calculation of model metrics
Written in C++ using
Rcpp, this package provides a collection of metrics for evaluating models.
r-modelr 0.1.2 — Helper functions for modelling in pipelines
Functions for modelling that help you seamlessly integrate modelling into a pipeline of data manipulation and visualisation.
r-modeltools 0.2-21 — Tools and classes for statistical models
This package provides a collection of tools to deal with statistical models. The functionality is experimental and the user interface is likely to change in the future.
r-motifrg 1.24.0 — Discover motifs in high throughput sequencing data
This package provides tools for discriminative motif discovery in high throughput genetic sequencing data sets using regression methods.
r-msnbase 2.6.1 — Base functions and classes for MS-based proteomics
This package provides basic plotting, data manipulation and processing of mass spectrometry based proteomics data.
r-msnid 1.14.0 — Utilities for LC-MSn proteomics identifications
This package extracts tandem mass spectrometry (MS/MS) ID data from mzIdentML (leveraging the mzID package) or text files. After collating the search results from multiple datasets it assesses their identification quality and optimize filtering criteria to achieve the maximum number of identifications while not exceeding a specified false discovery rate. It also contains a number of utilities to explore the MS/MS results and assess missed and irregular enzymatic cleavages, mass measurement accuracy, etc.
r-multitaper 1.0-14 — Multitaper spectral analysis tools
This package implements multitaper spectral estimation techniques using prolate spheroidal sequences (Slepians) and sine tapers for time series analysis. It includes an adaptive weighted multitaper spectral estimate, a coherence estimate, Thomson's Harmonic F-test, and complex demodulation. The Slepians sequences are generated efficiently using a tridiagonal matrix solution, and jackknifed confidence intervals are available for most estimates.
r-multtest 2.36.0 — Resampling-based multiple hypothesis testing
This package can do non-parametric bootstrap and permutation resampling-based multiple testing procedures (including empirical Bayes methods) for controlling the family-wise error rate (FWER), generalized family-wise error rate (gFWER), tail probability of the proportion of false positives (TPPFP), and false discovery rate (FDR). Several choices of bootstrap-based null distribution are implemented (centered, centered and scaled, quantile-transformed). Single-step and step-wise methods are available. Tests based on a variety of T- and F-statistics (including T-statistics based on regression parameters from linear and survival models as well as those based on correlation parameters) are included. When probing hypotheses with T-statistics, users may also select a potentially faster null distribution which is multivariate normal with mean zero and variance covariance matrix derived from the vector influence function. Results are reported in terms of adjusted P-values, confidence regions and test statistic cutoffs. The procedures are directly applicable to identifying differentially expressed genes in DNA microarray experiments.
r-munsell 0.5.0 — Munsell colour system
The Munsell package contains Functions for exploring and using the Munsell colour system.
r-mutationalpatterns 1.6.1 — Extract and visualize mutational patterns in genomic data
This package provides an extensive toolset for the characterization and visualization of a wide range of mutational patterns in SNV base substitution data.
r-mvtnorm 1.0-8 — Package for multivariate normal and t-distributions
This package can compute multivariate normal and t-probabilities, quantiles, random deviates and densities.
r-mzid 1.18.0 — Parser for mzIdentML files
This package provides a parser for mzIdentML files implemented using the XML package. The parser tries to be general and able to handle all types of mzIdentML files with the drawback of having less pretty output than a vendor specific parser.
r-mzr 2.14.0 — Parser for mass spectrometry data files
The mzR package provides a unified API to the common file formats and parsers available for mass spectrometry data. It comes with a wrapper for the ISB random access parser for mass spectrometry mzXML, mzData and mzML files. The package contains the original code written by the ISB, and a subset of the proteowizard library for mzML and mzIdentML. The netCDF reading code has previously been used in XCMS.
r-nbclust 3.0 — Determine the best number of clusters in a data set
NbClust provides 30 indexes for determining the optimal number of clusters in a data set and offers the best clustering scheme from different results to the user.
r-network 22.214.171.124 — Classes for relational data
This package provides tools to create and modify network objects. The
network class can represent a range of relational data types, and supports arbitrary vertex/edge/graph attributes.
r-nlme 3.1-137 — Linear and nonlinear mixed effects models
This package provides tools to fit and compare Gaussian linear and nonlinear mixed-effects models.
r-nloptr 1.0.4 — R interface to NLopt
This package is interface to NLopt, a library for nonlinear optimization. NLopt is a library for nonlinear optimization, providing a common interface for a number of different free optimization routines available online as well as original implementations of various other algorithms.
r-nmf 0.21.0 — Algorithms and framework for nonnegative matrix factorization
This package provides a framework to perform Non-negative Matrix Factorization (NMF). The package implements a set of already published algorithms and seeding methods, and provides a framework to test, develop and plug new or custom algorithms. Most of the built-in algorithms have been optimized in C++, and the main interface function provides an easy way of performing parallel computations on multicore machines.
r-nnet 7.3-12 — Feed-forward neural networks and multinomial log-linear models
This package provides functions for feed-forward neural networks with a single hidden layer, and for multinomial log-linear models.
r-np 0.60-8 — Non-parametric kernel smoothing methods for mixed data types
This package provides non-parametric (and semi-parametric) kernel methods that seamlessly handle a mix of continuous, unordered, and ordered factor data types.
r-numderiv 2016.8-1 — Accurate numerical derivatives
This package provides methods for calculating accurate numerical first and second order derivatives.
r-openssl 1.0.1 — Toolkit for encryption, signatures and certificates
This package provides R bindings to OpenSSL libssl and libcrypto, plus custom SSH pubkey parsers. It supports RSA, DSA and NIST curves P-256, P-384 and P-521. Cryptographic signatures can either be created and verified manually or via x509 certificates. AES block cipher is used in CBC mode for symmetric encryption; RSA for asymmetric (public key) encryption. High-level envelope functions combine RSA and AES for encrypting arbitrary sized data. Other utilities include key generators, hash functions (md5, sha1, sha256, etc), base64 encoder, a secure random number generator, and
bignum math methods for manually performing crypto calculations on large multibyte integers.
r-openxlsx 4.1.0 — Read, write and edit XLSX files
This package simplifies the creation of Excel
.xlsx files by providing a high level interface to writing, styling and editing worksheets. Through the use of Rcpp, read/write times are comparable to the
XLConnect packages with the added benefit of removing the dependency on Java.
r-optparse 1.6.0 — Command line option parser
This package provides a command line parser inspired by Python's
optparse library to be used with Rscript to write shebang scripts that accept short and long options.
r-org-ce-eg-db 3.5.0 — Genome wide annotation for Worm
This package provides mappings from Entrez gene identifiers to various annotations for the genome of the model worm Caenorhabditis elegans.
r-org-dm-eg-db 3.5.0 — Genome wide annotation for Fly
This package provides mappings from Entrez gene identifiers to various annotations for the genome of the model fruit fly Drosophila melanogaster.
r-org-hs-eg-db 3.5.0 — Genome wide annotation for Human
This package contains genome-wide annotations for Human, primarily based on mapping using Entrez Gene identifiers.
r-org-mm-eg-db 3.5.0 — Genome wide annotation for Mouse
This package provides mappings from Entrez gene identifiers to various annotations for the genome of the model mouse Mus musculus.
r-organismdbi 1.22.0 — Software to enable the smooth interfacing of database packages
The package enables a simple unified interface to several annotation packages each of which has its own schema by taking advantage of the fact that each of these packages implements a select methods.
r-pan 1.4 — Multiple imputation for multivariate panel or clustered data
This package implements multiple imputation for multivariate panel or clustered data.
r-parsedate 1.1.3 — Recognize and parse dates in various formats
This package provides three functions for dealing with dates:
parse_iso_8601 recognizes and parses all valid ISO 8601 date and time formats,
parse_date parses dates in unspecified formats, and
format_iso_8601 formats a date in ISO 8601 format.
r-pastecs 1.3.21 — Analysis of space-time ecological series
This package provides functions for regulation, decomposition and analysis of space-time series. The
pastecs library is a PNEC-Art4 and IFREMER initiative to bring PASSTEC 2000 functionalities to R.
r-pbapply 1.3-4 — Adding progress bar to apply functions
This lightweight package that adds progress bar to vectorized R functions apply. The implementation can easily be added to functions where showing the progress is useful e.g. bootstrap.
r-pbkrtest 0.4-7 — Methods for linear mixed model comparison
This package implements a parametric bootstrap test and a Kenward Roger modification of F-tests for linear mixed effects models and a parametric bootstrap test for generalized linear mixed models.
r-pcamethods 1.72.0 — Collection of PCA methods
This package provides Bayesian PCA, Probabilistic PCA, Nipals PCA, Inverse Non-Linear PCA and the conventional SVD PCA. A cluster based method for missing value estimation is included for comparison. BPCA, PPCA and NipalsPCA may be used to perform PCA on incomplete data as well as for accurate missing value estimation. A set of methods for printing and plotting the results is also provided. All PCA methods make use of the same data structure (pcaRes) to provide a common interface to the PCA results.
r-pcapp 1.9-73 — Robust PCA by projection pursuit
This package provides functions for robust principal component analysis (PCA) by projection pursuit.
r-pdist 1.2 — Partitioned distance function
Pdist computes the euclidean distance between rows of a matrix X and rows of another matrix Y. Previously, this could be done by binding the two matrices together and calling
dist, but this creates unnecessary computation by computing the distances between a row of X and another row of X, and likewise for Y. Pdist strictly computes distances across the two matrices, not within the same matrix, making computations significantly faster for certain use cases.
r-performanceanalytics 1.5.2 — Econometric tools for performance and risk analysis
This is a collection of econometric functions for performance and risk analysis. This package aims to aid practitioners and researchers in utilizing the latest research in analysis of non-normal return streams. In general, it is most tested on return (rather than price) data on a regular scale, but most functions will work with irregular return data as well, and increasing numbers of functions will work with P&L or price data where possible.
r-permute 0.9-4 — Functions for Generating Restricted Permutations of Data
This package provides a set of restricted permutation designs for freely exchangeable, line transects (time series), spatial grid designs and permutation of blocks (groups of samples).
permute also allows split-plot designs, in which the whole-plots or split-plots or both can be freely exchangeable.
r-phangorn 2.4.0 — Phylogenetic analysis in R
Phangorn is a package for phylogenetic analysis in R. It supports estimation of phylogenetic trees and networks using Maximum Likelihood, Maximum Parsimony, distance methods and Hadamard conjugation.
r-pheatmap 1.0.10 — Pretty heatmaps
This package provides an implementation of heatmaps that offers more control over dimensions and appearance.
r-phontools 0.2-2.1 — Tools for phonetic and acoustic analyses
This package contains tools for the organization, display, and analysis of the sorts of data frequently encountered in phonetics research and experimentation, including the easy creation of IPA vowel plots, and the creation and manipulation of WAVE audio files.
r-pillar 1.2.3 — Coloured formatting for columns
This package provides a
pillar generic designed for formatting columns of data using the full range of colours provided by modern terminals.
r-pkgconfig 2.0.1 — Private configuration for R packages
This package provides the functionality to set configuration options on a per-package basis. Options set by a given package only apply to that package, other packages are unaffected.
r-pkgmaker 0.27 — Package development utilities
This package provides some low-level utilities to use for R package development. It currently provides managers for multiple package specific options and registries, vignette, unit test and bibtex related utilities.
r-plogr 0.2.0 — R bindings for the plog C++ logging library
This package provides the header files for a stripped-down version of the plog header-only C++ logging library, and a method to log to R's standard error stream.
r-plotly 4.7.1 — Create interactive web graphics
This package enables the translation of ggplot2 graphs to an interactive web-based version and/or the creation of custom web-based visualizations directly from R. Once uploaded to a plotly account, plotly graphs (and the data behind them) can be viewed and modified in a web browser.
r-plotrix 3.7-2 — Various plotting functions
This package provides lots of plotting, various labeling, axis and color scaling functions for R.
r-pls 2.6-0 — Partial Least Squares and Principal Component Regression
The pls package implements multivariate regression methods: Partial Least Squares Regression (PLSR), Principal Component Regression (PCR), and Canonical Powered Partial Least Squares (CPPLS). It supports:
several algorithms: the traditional orthogonal scores (NIPALS) PLS algorithm, kernel PLS, wide kernel PLS, Simpls, and PCR through
multi-response models (or PLS2)
Jackknife variance estimates of regression coefficients
extensive and flexible plots: scores, loadings, predictions, coefficients, (R)MSEP, R², and correlation loadings
formula interface, modelled after
lm(), with methods for predict, print, summary, plot, update, etc.
extraction functions for coefficients, scores, and loadings
MSEP, RMSEP, and R² estimates
multiplicative scatter correction (MSC)
r-plyr 1.8.4 — Tools for Splitting, Applying and Combining Data
Plyr is a set of tools that solves a common set of problems: you need to break a big problem down into manageable pieces, operate on each piece and then put all the pieces back together. For example, you might want to fit a model to each spatial location or time point in your study, summarise data by panels or collapse high-dimensional arrays to simpler summary statistics.
r-png 0.1-7 — Read and write PNG images
This package provides an easy and simple way to read, write and display bitmap images stored in the PNG format. It can read and write both files and in-memory raw vectors.
r-powerlaw 0.70.1 — Tools for the analysis of heavy tailed distributions
This package provides an implementation of maximum likelihood estimators for a variety of heavy tailed distributions, including both the discrete and continuous power law distributions. Additionally, a goodness-of-fit based approach is used to estimate the lower cut-off for the scaling region.
r-powerplus 3.1 — Exponentiation operations
This package provides tools for the computation of matrix and scalar exponentiation.
r-prabclus 2.2-6 — Parametric bootstrap tests for spatial neighborhood clustering
This package provides distance-based parametric bootstrap tests for clustering with spatial neighborhood information. It implements some distance measures, clustering of presence-absence, abundance and multilocus genetical data for species delimitation, nearest neighbor based noise detection.
r-pracma 2.1.4 — Practical numerical math functions
This package provides functions for numerical analysis and linear algebra, numerical optimization, differential equations, plus some special functions. It uses Matlab function names where appropriate to simplify porting.
r-praise 1.0.0 — Functions to praise users
This package provides template functions to assist in building friendly R packages that praise their users.
r-preprocesscore 1.42.0 — Collection of pre-processing functions
This package provides a library of core pre-processing and normalization routines.
r-prettyunits 1.0.2 — Pretty, human readable formatting of quantities
This package provides tools for pretty, human readable formatting of quantities.
r-processx 3.1.0 — Execute and control system processes
This package provides portable tools to run system processes in the background. It can check if a background process is running; wait on a background process to finish; get the exit status of finished processes; kill background processes and their children; restart processes. It can read the standard output and error of the processes, using non-blocking connections.
processx can poll a process for standard output or error, with a timeout. It can also poll several processes at once.
r-prodlim 2018.04.18 — Product-limit estimation for censored event history analysis
This package provides a fast and user-friendly implementation of nonparametric estimators for censored event history (survival) analysis with the Kaplan-Meier and Aalen-Johansen methods.
r-progress 1.2.0 — Terminal progress bars
This package provides configurable progress bars. They may include percentage, elapsed time, and/or the estimated completion time. They work in terminals, in Emacs ESS, RStudio, Windows Rgui, and the macOS R.app. The package also provides a C++ API, that works with or without Rcpp.
r-promises 1.0.1 — Abstractions for promise-based asynchronous programming
r-protgenerics 1.12.0 — S4 generic functions for proteomics infrastructure
This package provides S4 generic functions needed by Bioconductor proteomics packages.
r-proto 1.0.0 — Prototype object-based programming
Proto is an object oriented system using object-based, also called prototype-based, rather than class-based object oriented ideas.
r-proxy 0.4-22 — Distance and similarity measures
This package provides an extensible framework for the efficient calculation of auto- and cross-proximities, along with implementations of the most popular ones.
r-prroc 1.3.1 — Precision-Recall and ROC curves for weighted and unweighted data
This package computes the areas under the precision-recall (PR) and ROC curve for weighted (e.g. soft-labeled) and unweighted data. In contrast to other implementations, the interpolation between points of the PR curve is done by a non-linear piecewise function. In addition to the areas under the curves, the curves themselves can also be computed and plotted by a specific S3-method.