This document discusses extending R with C code. It motivates combining R and C by noting that C code can speed up parts of R programs and allow access to C libraries. It then provides an example of calling a C function from R that returns an integer and examples of passing different R object types to C. It recommends compiling C code into a shared library and loading that into R using dyn.load.

1. Extend R with C!!!
2009/11/22 id:mickey24

2. id: mickey24 (@mickey24)

3. id: mickey24 (@mickey24)

5. • Tsukuba.R#4
• R Brainf*ck

6. • Tsukuba.R#4
• R Brainf*ck
• Tsukuba.R#5
• Animation with R

8. C R

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•

10. C R

11. C R
•C R

12. C R
•C R
•C R C
R

13. Motivation

14. Motivation
1.

15. Motivation
1.
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16. Motivation
1.
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• C R (40 50 ) www
- Seeking for my unique color.
http://d.hatena.ne.jp/syou6162/20090117/1232120983

17. Motivation
1.
•
• C R (40 50 ) www
- Seeking for my unique color.
http://d.hatena.ne.jp/syou6162/20090117/1232120983
2. R C

18. #include <R.h>
#include <Rinternals.h>
SEXP test(SEXP exp) {
...
}

19. C R
// integer
int n = INTEGER(exp)[0];
// string
PROTECT(exp = AS_CHARACTER(exp));
char* str = R_alloc(strlen(CHAR(
STRING_ELT(exp, 0))), sizeof(char));
strcpy(str, CHAR(STRING_ELT(exp, 0)));
...
UNPROTECT(1)

20. C R
// integer
SEXP exp_int;
PROTECT(exp_int = NEW_INTEGER(1));
int* pi = INTEGER_POINTER(exp_int);
pi[0] = 24;
...
UNPROTECT(1);
return exp_int;

22. $ R CMD SHLIB test.c

23. $ R CMD SHLIB test.c
• test.so

24. $ R CMD SHLIB test.c
• test.so
• R R

25. $ R CMD SHLIB test.c
• test.so
• R R
• Makefile Makevars

26. R C
dyn.load("test.so")
test <- function(n) {
.Call("test", integer(n))
}
test(24)
Writing R Extensions
http://cran.r-project.org/doc/contrib/manuals-jp/R-exts.jp.pdf

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29. •C R

30. •C R
• C
R

31. •C R
• C
R
• 6162

32. OpenCV

33. OpenCV
•

34. OpenCV
•
• BSD

35. OpenCV
•
• BSD
• C C++ Python

36. OpenCV
•
• BSD
• C C++ Python
•

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50. •
•C R

51. •
•C R
•

52. • C R - Seeking for my unique color.
http://d.hatena.ne.jp/syou6162/20090117/1232125870
• Writing R Extensions
http://cran.r-project.org/doc/contrib/manuals-jp/R-exts.jp.pdf