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Vectorised everything and made use of unique_ptr so there should be no more memory leaks. Hurrah for RAII
author Geogaddi\David <d.m.ronan@qmul.ac.uk>
date Wed, 12 Aug 2015 22:25:06 +0100
parents 25bf17994ef1
children
rev   line source
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d@0 3 <title>Guru Complex DFTs - FFTW 3.2.1</title>
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d@0 50 <a name="Guru-Complex-DFTs"></a>
d@0 51 Next:&nbsp;<a rel="next" accesskey="n" href="Guru-Real_002ddata-DFTs.html#Guru-Real_002ddata-DFTs">Guru Real-data DFTs</a>,
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d@0 56
d@0 57 <h4 class="subsection">4.5.3 Guru Complex DFTs</h4>
d@0 58
d@0 59 <pre class="example"> fftw_plan fftw_plan_guru_dft(
d@0 60 int rank, const fftw_iodim *dims,
d@0 61 int howmany_rank, const fftw_iodim *howmany_dims,
d@0 62 fftw_complex *in, fftw_complex *out,
d@0 63 int sign, unsigned flags);
d@0 64
d@0 65 fftw_plan fftw_plan_guru_split_dft(
d@0 66 int rank, const fftw_iodim *dims,
d@0 67 int howmany_rank, const fftw_iodim *howmany_dims,
d@0 68 double *ri, double *ii, double *ro, double *io,
d@0 69 unsigned flags);
d@0 70 </pre>
d@0 71 <p><a name="index-fftw_005fplan_005fguru_005fdft-240"></a><a name="index-fftw_005fplan_005fguru_005fsplit_005fdft-241"></a>
d@0 72 These two functions plan a complex-data, multi-dimensional DFT
d@0 73 for the interleaved and split format, respectively.
d@0 74 Transform dimensions are given by (<code>rank</code>, <code>dims</code>) over a
d@0 75 multi-dimensional vector (loop) of dimensions (<code>howmany_rank</code>,
d@0 76 <code>howmany_dims</code>). <code>dims</code> and <code>howmany_dims</code> should point
d@0 77 to <code>fftw_iodim</code> arrays of length <code>rank</code> and
d@0 78 <code>howmany_rank</code>, respectively.
d@0 79
d@0 80 <p><a name="index-flags-242"></a><code>flags</code> is a bitwise OR (`<samp><span class="samp">|</span></samp>') of zero or more planner flags,
d@0 81 as defined in <a href="Planner-Flags.html#Planner-Flags">Planner Flags</a>.
d@0 82
d@0 83 <p>In the <code>fftw_plan_guru_dft</code> function, the pointers <code>in</code> and
d@0 84 <code>out</code> point to the interleaved input and output arrays,
d@0 85 respectively. The sign can be either -1 (=
d@0 86 <code>FFTW_FORWARD</code>) or +1 (= <code>FFTW_BACKWARD</code>). If the
d@0 87 pointers are equal, the transform is in-place.
d@0 88
d@0 89 <p>In the <code>fftw_plan_guru_split_dft</code> function,
d@0 90 <code>ri</code> and <code>ii</code> point to the real and imaginary input arrays,
d@0 91 and <code>ro</code> and <code>io</code> point to the real and imaginary output
d@0 92 arrays. The input and output pointers may be the same, indicating an
d@0 93 in-place transform. For example, for <code>fftw_complex</code> pointers
d@0 94 <code>in</code> and <code>out</code>, the corresponding parameters are:
d@0 95
d@0 96 <pre class="example"> ri = (double *) in;
d@0 97 ii = (double *) in + 1;
d@0 98 ro = (double *) out;
d@0 99 io = (double *) out + 1;
d@0 100 </pre>
d@0 101 <p>Because <code>fftw_plan_guru_split_dft</code> accepts split arrays, strides
d@0 102 are expressed in units of <code>double</code>. For a contiguous
d@0 103 <code>fftw_complex</code> array, the overall stride of the transform should
d@0 104 be 2, the distance between consecutive real parts or between
d@0 105 consecutive imaginary parts; see <a href="Guru-vector-and-transform-sizes.html#Guru-vector-and-transform-sizes">Guru vector and transform sizes</a>. Note that the dimension strides are applied equally to the
d@0 106 real and imaginary parts; real and imaginary arrays with different
d@0 107 strides are not supported.
d@0 108
d@0 109 <p>There is no <code>sign</code> parameter in <code>fftw_plan_guru_split_dft</code>.
d@0 110 This function always plans for an <code>FFTW_FORWARD</code> transform. To
d@0 111 plan for an <code>FFTW_BACKWARD</code> transform, you can exploit the
d@0 112 identity that the backwards DFT is equal to the forwards DFT with the
d@0 113 real and imaginary parts swapped. For example, in the case of the
d@0 114 <code>fftw_complex</code> arrays above, the <code>FFTW_BACKWARD</code> transform
d@0 115 is computed by the parameters:
d@0 116
d@0 117 <pre class="example"> ri = (double *) in + 1;
d@0 118 ii = (double *) in;
d@0 119 ro = (double *) out + 1;
d@0 120 io = (double *) out;
d@0 121 </pre>
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