Displaying 2 results from an estimated 2 matches for "c_routines".
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2005 Oct 12
1
Using matprod from array.c
...rod(SEXP M, SEXP v, SEXP nr, SEXP nc) {
R_len_t nrm = INTEGER(nr)[0], ncm = INTEGER(nc)[0];
SEXP ans;
PROTECT(ans = allocMatrix(REALSXP, nrm, 1));
matprod(REAL(M), nrm, ncm,
REAL(v), ncm, 1, REAL(ans));
UNPROTECT(1);
return(ans);
}
When I try to make the DLL I get the following
D:\C_routines>RCMD SHLIB my_matprod.c
making my_matprod.d from my_matprod.c
gcc -IC:/R/tex/R-2.2.0/include -Wall -O2 -c my_matprod.c -o my_matprod.o
ar cr my_matprod.a my_matprod.o
ranlib my_matprod.a
gcc --shared -s -o my_matprod.dll my_matprod.def my_matprod.a -LC:/R/tex/R-2.
2.0/src/gnuwin32 -lg2c...
2005 Oct 03
1
storage.mode, C data types and speed
...XP v, SEXP a, SEXP nm, SEXP nv) {
int i = INTEGER(a)[0], i1 = 0, i2 = 0;
for ( ; i1 < INTEGER(nm)[0]; i2 = (++i2 == INTEGER(nv)[0]) ? 0 : i2) {
REAL(X)[i++] = REAL(M)[i1++] * REAL(v)[i2];
}
return(X);
}
Running this is R gives the following timings on my PC
> dyn.load("D:/C_routines/prod_integer")
> for(i in 1:3) {print(system.time(.Call("prod_integer", X, M, v, a, nm, nv)))}
[1] 0.17 0.00 0.18 NA NA
[1] 0.18 0.00 0.17 NA NA
[1] 0.15 0.00 0.17 NA NA
But strangely (to me) if I change the storage mode of my integers to "double", I get
&g...