Reading writing matrices in matlab

I have a 160000 x4 matrix generated on matlab. To write it onto a .txt file using dlmwrite takes forever, maybe around 8-12 hours. Is there any function which does this writing efficiently? I can save it however as .mat file, but can matlab .mat files be referred to in C/C++ codes and can we use the efficient writing techniques from there?

Answer 1

[Image Analyst]

Why can't you just write it out in binary with fwrite()?

[Bob]

if Mat is the 160000x4 matrix, just use fwrite(file,Mat) ? Is it better than dlmwrite?

[Ken Atwell]

'dlmwrite' will convert to text, while 'fwrite' will not. So, yes, 'fwrite' should be orders of magnitude faster. You would read the resulting file into a C problem with the C function 'fread'

[Bob]

Hi, I tried these lines

sym a b c d

Mat=[a b;c d]

>> FID = fopen('newfile.txt', 'wt');

>> fwrite(FID,sym2poly(Mat))

>> fclose(FID);

And the output is a set of randome characters in the newfile.txt

[Ken Atwell]

Well, not random. This is binary output suitable for reading in C with fread. The size of the file should be exactly 160000x4x8 bytes in size.