Hi, I have written a code for a discrete cosine transform which uses a matrix multiplication wherein a nested for loops have been employed and the computional time is more.So can you provide me a code which takes less computational time for a matrix of 8*8.

Hi. You need to look at the use of Fast Fourier Transforms (aka FFT). There are none currently on CodeCogs (that I know off); but I'm sure a search on Google should find some solutions. The great thing about FFTs is that the computation time scales according to NlogN process. i.e. almost linear.