CODE R ANALISIS - Code Analysis and Parallelizing Vector...

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Unformatted text preview: Code Analysis and Parallelizing Vector Operations in R Luke Tierney Department of Statistics & Actuarial Science University of Iowa DSC 2007 February, 2007 Luke Tierney (U. of Iowa) Code Analysis and Parallelization DSC 2007 1 / 17 Introduction R is a language for interactive data analysis and graphics. Some features intended to make interactive use easier: Named arguments. Partial matching of argument names. Lazy evaluation of arguments and use of argument expressions. R is also a powerful high level language well suited to expressing complex statistical computations Two concerns: correctness of code performance Luke Tierney (U. of Iowa) Code Analysis and Parallelization DSC 2007 2 / 17 Improving Correctness of R Code The R package system provides an infrastructure for testing: examples are run code in a tests directory is run by R CMD check . Unit testing frameworks have been developed, e.g. RUnit . Testing is essential there are issues: Most tests need to be created manually. Complete coverage is hard to achieve. Static code analysis is a useful supplement. Luke Tierney (U. of Iowa) Code Analysis and Parallelization DSC 2007 3 / 17 Static Code Analysis Static code analysis examines source code without executing it. Analysis can look at individual expressions larger patterns of expressions relationships among functions and modules For C, for example, compilers carry out basic code analysis and report errors more sophisticated tools have been developed recently these have been used successfully on the Linux kernel Most code analysis involves approximations not all issues can be detected (undecidable) there are false positives being able to tune specificity/sensitivity is helpful methods of ranking possible issues are useful statistical error ranking methods have been studies (Engler et al.) Luke Tierney (U. of Iowa) Code Analysis and Parallelization DSC 2007 4 / 17 Code Analysis for R The R language presents some unusual challenges: Whether a variable is global or local may depend on data....
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This note was uploaded on 05/12/2010 for the course APPLIED ST 2010 taught by Professor Various during the Spring '10 term at Universidad Nacional Agraria La Molina.

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CODE R ANALISIS - Code Analysis and Parallelizing Vector...

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