Mapping the 2d FFT index to another values

Hi,

I am trying to map one of the indices (the row index) of a 2d FFT matrix. I have tried to create a new row index (see the for loop below) and migrate the FFT magnitudes to a new 2d matrix which will be consisted of the new row index and old column index. However, I am not even sure if I am creating the new matrix (Phase_mul_stolt) right let alone migrating. Below is the coded I am working on.

% Implement 2_D FFT

[m,n] = size (raw_data);

twodfft = fft2(raw_data,2^nextpow2(m),2^nextpow2(n));

% Get the row and column indices of 2dFFT

Range_freq = (0:1:2047)*(fs/size_range); %row

Azimuth_freq = (0:1:2047)* (prf/size_azimuth);% column

%Map the Range_freq values to Range_freq_stolt and migrate the magnitudes

for k = 1:size_range

Range_freq_stolt(k) = (f0 + Range_freq(k)).* sqrt(1 - ((c * Azimuth_freq(k))/(2 * V .* (f0 + Range_freq(k)))).^2); % Range_freq_stolt is the new row index

Phase_mul_stolt(Range_freq_stolt(k),Azimuth_freq(k)) = abs(Phase_mul(k,k)); % magnitudes from Phase_mul should be migrated to Phase_mul_stolt

end

Any help will be highly appreciated. Many Thanks.