ca43827077
git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@9681 626c5289-ae23-0410-ae9c-e8d60b6d4f22
161 lines
4 KiB
HTML
161 lines
4 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<title>SWIG and R</title>
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<link rel="stylesheet" type="text/css" href="style.css">
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</head>
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<body bgcolor="#ffffff">
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<H1><a name="R_nn1"></a>32 SWIG and R</H1>
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<!-- INDEX -->
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<div class="sectiontoc">
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<ul>
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<li><a href="#R_nn2">Bugs</a>
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<li><a href="#R_nn3">Using R and SWIG</a>
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<li><a href="#R_nn4">Precompiling large R files</a>
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<li><a href="#R_nn5">General policy</a>
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<li><a href="#R_language_conventions">Language conventions</a>
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<li><a href="#R_nn6">C++ classes</a>
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<li><a href="#R_nn7">Enumerations</a>
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</ul>
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</div>
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<!-- INDEX -->
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<p>
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R is a GPL'ed open source statistical and plotting environment.
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Information about R can be found at <a
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href="http://www.r-project.org/">www.r-project.org</a>.
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The R bindings are under active development. They have been used to
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compile and run an R interface to QuantLib running on Mandriva Linux
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with gcc, and testing on other platforms is appreciated.
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</p>
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<H2><a name="R_nn2"></a>32.1 Bugs</H2>
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<p>
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Currently the following features are not implemented or broken:
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</p>
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<ul>
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<li>Garbage collection of created objects
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<li>C Array wrappings
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<li>tested on UNIX only, how well or badly it works on windows is not known
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</ul>
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<H2><a name="R_nn3"></a>32.2 Using R and SWIG</H2>
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<p>
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To use R and SWIG in C mode, execute the following commands where
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example.c is the name of the file with the functions in them
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</p>
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<div class="shell">
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<pre>
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swig -r example.i
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PKG_LIBS="example.c" R CMD SHLIB example_wrap.c
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</pre>
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</div>
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<p>
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The corresponding comments for C++ mode are
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</p>
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<div class="shell">
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<pre>
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swig -c++ -r example.i
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PKG_LIBS="example.cxx" R CMD SHLIB example_wrap.cpp
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</pre>
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</div>
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<p>
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Note that R is sensitive to the name of the file and to the file
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extension in C and C++ mode. The name of the wrapper file must be the
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name of the library. Also in C++ mode, the file extension must be cpp
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rather than cxx for the R compile command to recognize it.
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</p>
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<p>
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The commands produces two files. A dynamic shared object file called
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example_wrap.so and an R wrapper file called example_wrap.R. To load these
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files, start up R and type in the following commands
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</p>
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<div class="shell">
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<pre>
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dyn.load('example_wrap.so')
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source('example_wrap.R')
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cacheMetaData(1)
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</pre>
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</div>
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The cacheMetaData(1) will cause R to refresh its object tables.
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Without it, inheritance of wrapped objects may fail.
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<p>
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These two files can be loaded in any order
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</p>
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<H2><a name="R_nn4"></a>32.3 Precompiling large R files</H2>
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In cases where the R file is large, one make save a lot of loading
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time by precompiling the R wrapper. This can be done by creating the
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file makeRData.R which contains the following
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<pre>
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source('BigFile_wrap.R')
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save(list=ls(all=TRUE),file="BigFile_wrap.RData", compress=TRUE)
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q(save="no")
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</pre>
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This will generate a compiled R file called BigFile_wrap.RData that
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will save a large amount of loading time.
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<H2><a name="R_nn5"></a>32.4 General policy</H2>
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<p>
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The general policy of the module is to treat the C/C++ as a basic
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wrapping over the underlying functions and rely on the R type system
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to provide R syntax.
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</p>
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<H2><a name="R_language_conventions"></a>32.5 Language conventions</H2>
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<p>
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getitem and setitem use C++ conventions (i.e. zero based indices). [<-
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and [ are overloaded to allow for R syntax (one based indices and
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slices)
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</p>
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<H2><a name="R_nn6"></a>32.6 C++ classes</H2>
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<p>
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C++ objects are implemented as external pointer objects with the class
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being the mangled name of the class. The C++ classes are encapsulated
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as an SEXP with an external pointer type. The class is the mangled
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name of the class. The nice thing about R is that is allows you to
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keep track of the pointer object which removes the necessity for a lot
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of the proxy class baggage you see in other languages.
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</p>
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<H2><a name="R_nn7"></a>32.7 Enumerations</H2>
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<p>
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enumerations are characters which are then converted back and forth to
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ints before calling the C routines. All of the enumeration code is
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done in R.
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</p>
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</body>
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</html>
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