Sorry for not including enough information everyone.
I have quite a bit of code, so I will just enter relevant pieces...
This is how I call C from R:
The tstats are tstatistics (difference of mean, divided by sqrt of S1+S2)
from an unpermuted matrix. The c code is below...
dyn.load(testp.so)
obj-.C(testp,ptests=as.array(permuted_ttests),as.integer(B),permuted1=as.array(permuted),matrix=as.array(Imatrix),
as.integer(ncols), as.integer(nrows),as.integer(g)*,as.array(abs(tstats)*
),pvalues=as.array(ps))
to test, I decided not to permute my matrix and just send it the original
matrix, Imatrix. Everything in C is a double, or if I use an integer, I cast
it to a double (to divide and get mean, etc). I then compare the values of
the tstats that I sent into C and the tsats I calculate within C...
The following is my C code:
void testp(double *permuted_ttests,int *B,double *permuted,double
*Imatrix,int *nc,int *nr,int *g,*double *Tinitial*,double *ps) {
after which, using the variable above I take the mean of certain elements
(currently the unpermuted matrix to test) via other functions using the same
double and pointers and I store them in C1 and C2 and solve for an absolute
T statistic - and print it (I erased the Ts earlier).
for (i=0; i*nr; i++){
xbardiff = C1[i][0]-C2[i][0];
denom = sqrt(C1[i][2]+C2[i][2]);
* Ts[i]=fabs(xbardiff/denom);*
* Rprintf(%f Ts\n,Ts[i]);*
*
if (fabs(Ts[i])fabs(Tinitial[i])){ //summing of permueted_ttests
counter[i]++;
Rprintf(ts %f and tinitial %f \n, Ts[i],Tinitial[i]);
}
*
etc...
The issue here - is that I get a few that when printed it appears that they
were rounded up - causing my counter[i] to ++ in some cases.
Should I send more code?
Sorry and thank you very much,
On Fri, Jul 9, 2010 at 6:18 AM, Duncan Murdoch murdoch.dun...@gmail.comwrote:
Joseph N. Paulson wrote:
Hi all!
I am currently writing a C-module for a for loop in which I permute
columns
in a matrix (bootstrapping) and I send a couple of variables into C
initially. All of it is working, except the initial values I send to R are
rounded/truncated (I believe rounded).
I am using a 32 bit machine to compile, I am using (I believe) 32 bit
R
While debugging I print the values I am sending to C, and then I print the
same values using Rprintf and the number gets rounded to 10^-6, which is
actually causing some errors for me. Is there any way to correct/prevent
the
error?
sample output from R
[1,] 1.000
[2,] 1.0256242
[3,] 1.1826277
[4,] -0.6937246
[5,] 1.3633604
sample output from C
1.00
1.025624
1.182628
0.693725
1.363360
It looks as though you are confusing the display of numbers with their
internal values. R is printing 7 decimal places, C is printing 6. As far
as we can tell, that's the only difference.
Duncan Murdoch
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PLEASE do read the posting guide
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and provide commented, minimal, self-contained, reproducible code.
__
R-help@r-project.org mailing list
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
- Joseph N. Paulson
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__
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
