From: Elizabeth Lawson <lizzylaws_at_yahoo.com>

Date: Sat 01 Oct 2005 - 04:45:53 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Oct 01 04:53:47 2005

Date: Sat 01 Oct 2005 - 04:45:53 EST

Hi,

I am hoping some one can help me. I am learning to use C and would like to learn how to call c code in R. I have look at Writing R Extensions

and I tried to copy the example on page 38

void convolve(double *a, int *na, double *b, int *nb, double *ab)

{

int i, j, nab = *na + *nb - 1;

for(i = 0; i < nab; i++)

ab[i] = 0.0;

for(i = 0; i < *na; i++)

for(j = 0; j < *nb; j++)

ab[i + j] += a[i] * b[j];

}

called from R by

conv <- function(a, b)

.C("convolve",

as.double(a),

as.integer(length(a)),

as.double(b),

as.integer(length(b)),

ab = double(length(a) + length(b) - 1))$ab

and I got the error "C" function name not in load table.

Do I need to compile the C code first?

Do I need a c copmiler at all?

Any suggestions for a begginner?

Thanks,

Elizabeth Lawson

I

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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Oct 01 04:53:47 2005

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