title: Which is the correct way of cufft plan configuration in case of 3d fft's?
body: <p>Lets say I have a 3 dimensional(x=256+2,y=256,z=128) array and I want to compute the FFT (forward and inverse) using cuFFT. And I have a fftw compatible data layout lets say the padding is in the x direction as shown in the size above(+2). How my plan should be ? </p>
  
  <pre><code>//forward 
  cufftPlan3d(&amp;plan, z, y, x, CUFFT_R2C) 
  
  //or
  cufftPlan3d(&amp;plan, x, y, z, CUFFT_R2C) 
  </code></pre>
  
  <p>and for inverse ? </p>
  
  <pre><code>//Inverse 
  cufftPlan3d(&amp;plan, x, y, z, CUFFT_C2R) 
  
  //or
  cufftPlan3d(&amp;plan, z, y, x, CUFFT_C2R) 
  </code></pre>
  
  <p>If the data is stored in <strong>column major</strong> order how is that going to affect the <strong>plan creation</strong> ? </p>