Chris@41: 
Chris@93: module yetilab.transform.fft;
Chris@41: 
Chris@41: import edu.emory.mathcs.jtransforms.fft: DoubleFFT_1D;
Chris@41: 
Chris@93: b = load yetilab.block.block;
Chris@93: vec = load yetilab.block.fvector;
Chris@93: complex = load yetilab.block.complex;
Chris@41: 
Chris@48: packedToComplex p =
Chris@46:    (n = (vec.length p) / 2;
Chris@46:     array
Chris@46:        (map do i:
Chris@46:             re = if i == n then p[1] else p[i*2] fi;
Chris@46:             im = if i == 0 or i == n then 0 else p[i*2+1] fi;
Chris@46:             complex.complex re im;
Chris@46:         done [0..n]));
Chris@41: 
Chris@48: complexToPacked arr =
Chris@48:    (n = length arr;
Chris@48:     v = vec.vector
Chris@48:        (map do i:
Chris@48:             ix = int (i/2);
Chris@48:             if i == ix*2 then
Chris@48:                 complex.real arr[ix]
Chris@48:             else 
Chris@48:                 complex.imaginary arr[ix] 
Chris@48:             fi;
Chris@48:             done [0..(n-1)*2-1]);
Chris@48:     v[1] := complex.real arr[n-1];
Chris@48:     v);
Chris@48: 
Chris@48: realForward n = 
Chris@41:    (d = new DoubleFFT_1D(n);
Chris@41:     do bl:
Chris@47:         v = b.vector bl;
Chris@41:         d#realForward(v);
Chris@48:         packedToComplex v;
Chris@48:     done);
Chris@48: 
Chris@48: realInverse n = 
Chris@48:    (d = new DoubleFFT_1D(n);
Chris@48:     do arr:
Chris@48:         v = complexToPacked arr;
Chris@48:         d#realInverse(v, true);
Chris@48:         b.block v;
Chris@41:     done);
Chris@41: 
Chris@41: {
Chris@48: realForward,
Chris@48: realInverse,
Chris@41: }
Chris@41: