Using specific transform from fftw library

Hi! So I'm trying to use a specific transform in the FFTW library (the REDFT01 (DCT-III) transform) but I'm not sure how I can access this through Matlab. My understanding is that the fftw command in Matlab only computes the standard fft using the most efficient algorithm based on the data to be analyzed, not a staggered grid cosine transform like the one I need.

I was wondering if I could use this transform directly in Matlab or if I have to use mex files to run the C code from the fftw package in Matlab?

Any other suggestions for trying to compute this transform efficiently would be very helpful. Thanks a lot!

[B Treeby]

My understanding is that MATLAB only links to the complex-to-complex transforms in FFTW. Some time ago I wrote a MEX interface to FFTW to use the DCT and DST transforms within MATLAB. I've just made it available via GitHub and the file exchange in case it's helpful: https://www.mathworks.com/matlabcentral/fileexchange/75071-matlab-discrete-trigonometric-transform-library

[jassem44]

I ended up doing almost exactly what you suggested. I found a writeup of the function in C++ (from the book Numerical Recipes) and wrote a MEX interface. In any case, thank you very much for the response.