On Thu, 17 Mar 2005, Oleg Sklyar wrote:

Dear Simon,

you gave us only a fragment of your code, so I can only guess what the
problem is:

What is imgSize? The behavior you describe seems as if you re-using the
imgSize SEXP in all elements.
AFAIR in your case setAttrib doesn't copy the value, so you need to do so
yourself (or alloc new dim array
for each element).

Sorry, it is always a tradeoff - either to explain or put a relatively large code, which also uses non-standard libraries making the code difficult to read. imgSize values are reset in between: see the full code below. The SEXP pointer imgSize stays in tact, that's true, but its values are changed (the problem is, they are always the last in the row). I.e. if I have 3 images 40x20, 200x100 and 150x75 I will get three matrices of 150x75, but if I omit setAtrib and return vectors I get vectors of different length.

So, as Simon says, you need to create separate objects for the dimensions of each matrix, not share the object. It is the object pointed to by imgSize you have attached as the dimensions, not the values.


BTW, setAttrib(element, R_DimSymbol, imgSize) just calls dimgets(element, imgSize), so I would have used the latter directly.

I believe you do not have three matrices of 150x75, rather a vector of length 40*20 with an inconsistent dim attribute of c(150, 75), etc.


Oleg

SEXP load2DImages(SEXP fileNames) {
int nFiles = LENGTH(fileNames);
std::cout << "Loading " << nFiles << " files..." << std::endl;
// SEXP result = allocList(nFiles);
SEXP result = allocVector(VECSXP, nFiles);
PROTECT(result);
SEXP imgSize = allocVector(INTSXP, 2);
PROTECT(imgSize);
TRGB2DImage::Pointer image;
TRGB2DReader::Pointer reader = TRGB2DReader::New();
TRGB2DImage::SizeType size; TRGB2DImage::IndexType pixIndex;
for (int i = 0; i < nFiles; i++) {
try {
char *filename = CHAR(asChar(VECTOR_ELT(fileNames, i)));
std::cout << std::endl << "Loading image file " << filename << "... ";
reader->SetFileName(filename);
reader->Update();
image = reader->GetOutput();
} catch(...) {
std::cout << "failed!";
continue;
}
std::cout << std::endl;
size = image->GetLargestPossibleRegion().GetSize();
INTEGER(imgSize)[0] = size[1];
INTEGER(imgSize)[1] = size[0];
std::cout << size[0] << " x " << size[1] << std::endl;
SET_VECTOR_ELT(result, i, allocVector(INTSXP, size[0] * size[1]));
SEXP element = VECTOR_ELT(result, i);
for (int ix = 0; ix < size[0]; ix++) {
pixIndex[0] = ix;
for (int iy = 0; iy < size[1]; iy++) {
pixIndex[1] = iy;
INTEGER(element)[size[1] * ix + iy] = getIntRGBColour(image->GetPixel(pixIndex));
}
}
setAttrib(element, R_DimSymbol, imgSize);
}
UNPROTECT(2);
if (nFiles == 1)
return VECTOR_ELT(result, 0);
else
return result;
}


Dr Oleg Sklyar
European Bioinformatics Institute
Wellcome Trust Genome Campus
Hinxton, Cambridge, CB10 1SD
England
phone/fax  +44(0)1223 49 4478/4468
e-mail [EMAIL PROTECTED]



Simon Urbanek wrote:

Oleg,

you gave us only a fragment of your code, so I can only guess what the problem is:

On Mar 16, 2005, at 12:40 PM, Oleg Sklyar wrote:

// converting element into a matrix
setAttrib(element, R_DimSymbol, imgSize);


What is imgSize? The behavior you describe seems as if you re-using the imgSize SEXP in all elements. AFAIR in your case setAttrib doesn't copy the value, so you need to do so yourself (or alloc new dim array for each element).

Cheers,
Simon




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