Commit 0efe8b8f authored by Andrew Heather's avatar Andrew Heather
Browse files

ENH: FFT - replaced Numerical Recipes-based FFT by the FFTW library

parent cc36db19
#!/bin/sh
cd ${0%/*} || exit 1 # run from this directory
# Parse arguments for library compilation
targetType=libso
. $WM_PROJECT_DIR/wmake/scripts/AllwmakeParseArguments
if [ -f "$FFTW_ARCH_PATH/include/fftw3.h" ] || \
[ "${FFTW_ARCH_PATH##*-}" = system -a -f "/usr/include/fftw3.h" ]
then
wmake $targetType
else
echo
echo "Skipping randomProcesses library (no FFTW)"
echo
fi
#------------------------------------------------------------------------------
......@@ -2,8 +2,8 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\/ M anipulation |
\\ / A nd | Copyright (C) 2011-2015 OpenFOAM Foundation
\\/ M anipulation | Copyright (C) 2016 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
......@@ -24,7 +24,8 @@ License
\*---------------------------------------------------------------------------*/
#include "fft.H"
#include "fftRenumber.H"
#include <fftw3.h>
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
......@@ -33,16 +34,11 @@ namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#define SWAP(a,b) tempr=(a); (a)=(b); (b)=tempr
#define TWOPI 6.28318530717959
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
void fft::transform
(
complexField& field,
const labelList& nn,
transformDirection isign
transformDirection dir
)
{
forAll(nn, idim)
......@@ -59,128 +55,58 @@ void fft::transform
}
}
const label ndim = nn.size();
// Copy field into fftw containers
label N = field.size();
fftw_complex in[N], out[N];
label i1, i2, i3, i2rev, i3rev, ip1, ip2, ip3, ifp1, ifp2;
label ibit, k1, k2, n, nprev, nrem, idim;
scalar tempi, tempr;
scalar theta, wi, wpi, wpr, wr, wtemp;
scalar* data = reinterpret_cast<scalar*>(field.begin()) - 1;
// if inverse transform : renumber before transform
if (isign == REVERSE_TRANSFORM)
forAll(field, i)
{
fftRenumber(field, nn);
in[i][0] = field[i].Re();
in[i][1] = field[i].Im();
}
// Create the plan
// FFTW_FORWARD = -1
// FFTW_BACKWARD = 1
label ntot = 1;
forAll(nn, idim)
{
ntot *= nn[idim];
}
// 1-D plan
// fftw_plan plan =
// fftw_plan_dft_1d(N, in, out, FFTW_FORWARD, FFTW_ESTIMATE);
nprev = 1;
// Generic 1..3-D plan
label rank = nn.size();
fftw_plan plan =
fftw_plan_dft(rank, nn.begin(), in, out, dir, FFTW_ESTIMATE);
for (idim=ndim; idim>=1; idim--)
{
n = nn[idim-1];
nrem = ntot/(n*nprev);
ip1 = nprev << 1;
ip2 = ip1*n;
ip3 = ip2*nrem;
i2rev = 1;
for (i2=1; i2<=ip2; i2+=ip1)
{
if (i2 < i2rev)
{
for (i1=i2; i1<=i2 + ip1 - 2; i1+=2)
{
for (i3=i1; i3<=ip3; i3+=ip2)
{
i3rev = i2rev + i3 - i2;
SWAP(data[i3], data[i3rev]);
SWAP(data[i3 + 1], data[i3rev + 1]);
}
}
}
ibit = ip2 >> 1;
while (ibit >= ip1 && i2rev > ibit)
{
i2rev -= ibit;
ibit >>= 1;
}
i2rev += ibit;
}
// Compute the FFT
fftw_execute(plan);
ifp1 = ip1;
while (ifp1 < ip2)
{
ifp2 = ifp1 << 1;
theta = isign*TWOPI/(ifp2/ip1);
wtemp = sin(0.5*theta);
wpr = -2.0*wtemp*wtemp;
wpi = sin(theta);
wr = 1.0;
wi = 0.0;
for (i3 = 1; i3 <= ifp1; i3 += ip1)
{
for (i1 = i3; i1 <= i3 + ip1 - 2; i1 += 2)
{
for (i2 = i1; i2 <= ip3; i2 += ifp2)
{
k1 = i2;
k2 = k1 + ifp1;
tempr = scalar(wr*data[k2]) - scalar(wi*data[k2 + 1]);
tempi = scalar(wr*data[k2 + 1]) + scalar(wi*data[k2]);
data[k2] = data[k1] - tempr;
data[k2 + 1] = data[k1 + 1] - tempi;
data[k1] += tempr;
data[k1 + 1] += tempi;
}
}
wr = (wtemp = wr)*wpr - wi*wpi + wr;
wi = wi*wpr + wtemp*wpi + wi;
}
ifp1 = ifp2;
}
nprev *= n;
}
// if forward transform : renumber after transform
if (isign == FORWARD_TRANSFORM)
forAll(field, i)
{
fftRenumber(field, nn);
field[i].Re() = out[i][0];
field[i].Im() = out[i][1];
}
fftw_destroy_plan(plan);
// scale result (symmetric scale both forward and inverse transform)
/*
fftw_real in[N], out[N];
// Create a plan for real data input
// - generates 1-sided FFT
// - direction given by FFTW_R2HC or FFTW_HC2R.
// - in[N] is the array of real input val ues
// - out[N] is the array of N/2 real valuea followed by N/2 complex values
// - 0 component = DC component
fftw_plan plan = fftw_plan_r2r_2d(N, in, out, FFTW_R2HC, FFTW_ESTIMATE)
scalar recRootN = 1.0/sqrt(scalar(ntot));
// Compute the FFT
fftw_execute(plan);
forAll(field, i)
{
field[i] *= recRootN;
}
fftw_destroy_plan(plan);
*/
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#undef SWAP
#undef TWOPI
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
tmp<complexField> fft::forwardTransform
......
......@@ -3,7 +3,7 @@
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011 OpenFOAM Foundation
\\/ M anipulation |
\\/ M anipulation | Copyright (C) 2016 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
......@@ -25,11 +25,10 @@ Class
Foam::fft
Description
Fast fourier transform derived from the Numerical
Recipes in C routine.
Fast fourier transform using the fftw library.
The complex transform field is returned in the field supplied. The
direction of transform is supplied as an argument (1 = forward, -1 =
direction of transform is supplied as an argument (-1 = forward, 1 =
reverse). The dimensionality and organisation of the array of values
in space is supplied in the nn indexing array.
......@@ -56,8 +55,8 @@ public:
enum transformDirection
{
FORWARD_TRANSFORM = 1,
REVERSE_TRANSFORM = -1
FORWARD_TRANSFORM = -1,
REVERSE_TRANSFORM = 1
};
......
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
Description
Multi-dimensional renumbering used in the Numerical Recipes
fft routine. This version is recursive, so works in n-d :
determined by the length of array nn
\*---------------------------------------------------------------------------*/
#include "fftRenumber.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
void Foam::fftRenumberRecurse
(
List<complex>& data,
List<complex>& renumData,
const labelList& nn,
label nnprod,
label ii,
label l1,
label l2
)
{
if (ii == nn.size())
{
// we've worked out the renumbering scheme. Now copy
// the components across
data[l1] = complex(renumData[l2].Re(),renumData[l2].Im());
}
else
{
// do another level of folding. First work out the
// multiplicative value of the index
nnprod /= nn[ii];
label i_1(0);
for (label i=0; i<nn[ii]; i++)
{
// now evaluate the indices (both from array 1 and to
// array 2). These get multiplied by nnprod to (cumulatively)
// find the real position in the list corresponding to
// this set of indices.
if (i<nn[ii]/2)
{
i_1 = i + nn[ii]/2;
}
else
{
i_1 = i - nn[ii]/2;
}
// go to the next level of recursion.
fftRenumberRecurse
(
data,
renumData,
nn,
nnprod,
ii+1,
l1+i*nnprod,
l2+i_1*nnprod
);
}
}
}
void Foam::fftRenumber
(
List<complex>& data,
const labelList& nn
)
{
List<complex> renumData(data);
label nnprod(1);
forAll(nn, i)
{
nnprod *= nn[i];
}
label ii(0), l1(0), l2(0);
fftRenumberRecurse
(
data,
renumData,
nn,
nnprod,
ii,
l1,
l2
);
}
// ************************************************************************* //
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
Global
fftRenumber
Description
Multi-dimensional renumbering used in the Numerical Recipes
fft routine.
SourceFiles
fftRenumber.C
\*---------------------------------------------------------------------------*/
#ifndef fftRenumber_H
#define fftRenumber_H
#include "complex.H"
#include "List.H"
#include "labelList.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// Recursively evaluate the indexing necessary to do the folding of the fft
// data. We recurse until we have the indexing ncessary for the folding in all
// directions.
void fftRenumberRecurse
(
List<complex>& data,
List<complex>& renumData,
const labelList& nn,
label nnprod,
label ii,
label l1,
label l2
);
// Fold the n-d data array to get the fft components in the right places.
void fftRenumber
(
List<complex>& data,
const labelList& nn
);
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //
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