mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 08:37:25 -05:00
#2567 Reduces memory overhead by extending the JTransforms FFT package to reuse its float array when calculaing the inverse FFT in the channelizer for a subset of the FFT size operations. (#2568)
Co-authored-by: sheirerd <sheirerd@ainfosec.com>
This commit is contained in:
Denny Sheirer
@@ -0,0 +1,779 @@
|
||||
/*
|
||||
* *****************************************************************************
|
||||
* Copyright (C) 2014-2026 Dennis Sheirer
|
||||
*
|
||||
* This program 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.
|
||||
*
|
||||
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>
|
||||
* ****************************************************************************
|
||||
*
|
||||
* The transform kernels in this class are ported from the mixed radix complex FFT (cffti, cfftf and passf2/3/4/5)
|
||||
* in JTransforms org.jtransforms.fft.FloatFFT_1D, which carries the following license:
|
||||
*
|
||||
* JTransforms
|
||||
* Copyright (c) 2007 onward, Piotr Wendykier
|
||||
* All rights reserved.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright notice, this
|
||||
* list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
||||
* this list of conditions and the following disclaimer in the documentation
|
||||
* and/or other materials provided with the distribution.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
||||
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
||||
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
|
||||
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
||||
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||||
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
|
||||
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
|
||||
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
*/
|
||||
package io.github.dsheirer.dsp.fft;
|
||||
|
||||
/**
|
||||
* Allocation-free mixed radix complex FFT for sizes that factor into 2, 3 and 5 only.
|
||||
*
|
||||
* This is a port of the JTransforms FloatFFT_1D mixed radix complex transform path. JTransforms allocates a new
|
||||
* 2N float scratch array on every mixed radix transform, which creates significant garbage collection pressure when
|
||||
* the transform runs at block rate (e.g. the polyphase channelizer IFFT). This implementation pre-allocates the
|
||||
* scratch buffer once and reuses it for each transform.
|
||||
*
|
||||
* Results match JTransforms FloatFFT_1D complexForward() and complexInverse(): the forward transform uses the
|
||||
* exp(-j...) kernel, the inverse uses exp(+j...), and the inverse optionally scales by 1/N. Twiddle factors are
|
||||
* calculated in double precision, so results can differ from JTransforms in the least significant bits.
|
||||
*
|
||||
* Samples are interleaved complex: a[offset + 2k] = Re[k] and a[offset + 2k + 1] = Im[k] for 0 <= k < N.
|
||||
*
|
||||
* Note: this class is NOT thread-safe since it reuses an internal scratch buffer. Use one instance per thread.
|
||||
*/
|
||||
public class MixedRadixComplexFFT
|
||||
{
|
||||
private static final int[] FACTORS = {4, 2, 3, 5};
|
||||
private static final int FORWARD = -1;
|
||||
private static final int INVERSE = 1;
|
||||
|
||||
private final int mSize;
|
||||
private final int[] mFactors;
|
||||
private final float[] mTwiddles;
|
||||
private final float[] mScratch;
|
||||
private final float mScale;
|
||||
|
||||
/**
|
||||
* Constructs an instance
|
||||
* @param size of the transform in complex samples. Must be a positive value with no prime factors other than
|
||||
* 2, 3 and 5.
|
||||
* @throws IllegalArgumentException if the size is not supported
|
||||
*/
|
||||
public MixedRadixComplexFFT(int size)
|
||||
{
|
||||
if(!isSupported(size))
|
||||
{
|
||||
throw new IllegalArgumentException("Unsupported FFT size [" + size +
|
||||
"] - size must be positive and have no prime factors other than 2, 3 and 5");
|
||||
}
|
||||
|
||||
mSize = size;
|
||||
mFactors = factorize(size);
|
||||
mTwiddles = new float[2 * size + 2];
|
||||
mScratch = new float[2 * size];
|
||||
mScale = 1.0f / size;
|
||||
calculateTwiddles();
|
||||
}
|
||||
|
||||
/**
|
||||
* Indicates if the size can be transformed by this class.
|
||||
* @param size in complex samples
|
||||
* @return true if the size is positive and has no prime factors other than 2, 3 and 5.
|
||||
*/
|
||||
public static boolean isSupported(int size)
|
||||
{
|
||||
if(size < 1)
|
||||
{
|
||||
return false;
|
||||
}
|
||||
|
||||
int remainder = size;
|
||||
|
||||
for(int factor: new int[]{2, 3, 5})
|
||||
{
|
||||
while(remainder % factor == 0)
|
||||
{
|
||||
remainder /= factor;
|
||||
}
|
||||
}
|
||||
|
||||
return remainder == 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* Size of this transform
|
||||
* @return size in complex samples
|
||||
*/
|
||||
public int getSize()
|
||||
{
|
||||
return mSize;
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes the forward DFT of the interleaved complex samples, in place. Equivalent to JTransforms
|
||||
* FloatFFT_1D.complexForward(samples, offset).
|
||||
* @param samples interleaved complex, with at least 2N values from the offset
|
||||
* @param offset to the first sample
|
||||
*/
|
||||
public void forward(float[] samples, int offset)
|
||||
{
|
||||
transform(samples, offset, FORWARD);
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes the forward DFT of the interleaved complex samples, in place.
|
||||
* @param samples interleaved complex, with at least 2N values
|
||||
*/
|
||||
public void forward(float[] samples)
|
||||
{
|
||||
forward(samples, 0);
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes the inverse DFT of the interleaved complex samples, in place. Equivalent to JTransforms
|
||||
* FloatFFT_1D.complexInverse(samples, offset, scale).
|
||||
* @param samples interleaved complex, with at least 2N values from the offset
|
||||
* @param offset to the first sample
|
||||
* @param scale true to scale the results by 1/N
|
||||
*/
|
||||
public void inverse(float[] samples, int offset, boolean scale)
|
||||
{
|
||||
transform(samples, offset, INVERSE);
|
||||
|
||||
if(scale && mSize > 1)
|
||||
{
|
||||
int end = offset + 2 * mSize;
|
||||
|
||||
for(int x = offset; x < end; x++)
|
||||
{
|
||||
samples[x] *= mScale;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes the inverse DFT of the interleaved complex samples, in place.
|
||||
* @param samples interleaved complex, with at least 2N values
|
||||
* @param scale true to scale the results by 1/N
|
||||
*/
|
||||
public void inverse(float[] samples, boolean scale)
|
||||
{
|
||||
inverse(samples, 0, scale);
|
||||
}
|
||||
|
||||
/**
|
||||
* Factors the size into the radix sequence used by the transform, ported from JTransforms cffti(). Radix 4 is
|
||||
* preferred, then 2, 3 and 5, and a radix 2 factor is moved to the front of the sequence.
|
||||
*/
|
||||
private static int[] factorize(int size)
|
||||
{
|
||||
if(size == 1)
|
||||
{
|
||||
return new int[0];
|
||||
}
|
||||
|
||||
int[] factors = new int[32];
|
||||
int count = 0;
|
||||
int remainder = size;
|
||||
|
||||
for(int factor: FACTORS)
|
||||
{
|
||||
while(remainder % factor == 0)
|
||||
{
|
||||
factors[count++] = factor;
|
||||
remainder /= factor;
|
||||
|
||||
if(factor == 2 && count != 1)
|
||||
{
|
||||
System.arraycopy(factors, 0, factors, 1, count - 1);
|
||||
factors[0] = 2;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if(remainder != 1)
|
||||
{
|
||||
throw new IllegalArgumentException("Unsupported FFT size [" + size + "]");
|
||||
}
|
||||
|
||||
int[] result = new int[count];
|
||||
System.arraycopy(factors, 0, result, 0, count);
|
||||
return result;
|
||||
}
|
||||
|
||||
/**
|
||||
* Calculates the twiddle factor table, ported from JTransforms cffti() with the table offset removed and the
|
||||
* angles calculated in double precision.
|
||||
*/
|
||||
private void calculateTwiddles()
|
||||
{
|
||||
if(mSize == 1)
|
||||
{
|
||||
return;
|
||||
}
|
||||
|
||||
double angleIncrement = 2.0 * Math.PI / mSize;
|
||||
int i = 1;
|
||||
int l1 = 1;
|
||||
|
||||
for(int factor: mFactors)
|
||||
{
|
||||
int ld = 0;
|
||||
int l2 = l1 * factor;
|
||||
int ido = mSize / l2;
|
||||
int idot = ido + ido + 2;
|
||||
|
||||
for(int j = 1; j < factor; j++)
|
||||
{
|
||||
mTwiddles[i - 1] = 1;
|
||||
mTwiddles[i] = 0;
|
||||
ld += l1;
|
||||
int fi = 0;
|
||||
double argld = ld * angleIncrement;
|
||||
|
||||
for(int ii = 4; ii <= idot; ii += 2)
|
||||
{
|
||||
i += 2;
|
||||
fi++;
|
||||
double arg = fi * argld;
|
||||
mTwiddles[i - 1] = (float)Math.cos(arg);
|
||||
mTwiddles[i] = (float)Math.sin(arg);
|
||||
}
|
||||
}
|
||||
|
||||
l1 = l2;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Performs the transform, ported from JTransforms cfftf() using the reusable scratch buffer.
|
||||
* @param a samples
|
||||
* @param offa offset to first sample
|
||||
* @param isign -1 for forward and +1 for inverse
|
||||
*/
|
||||
private void transform(float[] a, int offa, int isign)
|
||||
{
|
||||
if(mSize == 1)
|
||||
{
|
||||
return;
|
||||
}
|
||||
|
||||
float[] ch = mScratch;
|
||||
int twon = 2 * mSize;
|
||||
boolean inScratch = false;
|
||||
int l1 = 1;
|
||||
int iw = 0;
|
||||
|
||||
for(int factor: mFactors)
|
||||
{
|
||||
int l2 = factor * l1;
|
||||
int idot = 2 * (mSize / l2);
|
||||
|
||||
switch(factor)
|
||||
{
|
||||
case 4:
|
||||
if(inScratch)
|
||||
{
|
||||
passf4(idot, l1, ch, 0, a, offa, iw, isign);
|
||||
}
|
||||
else
|
||||
{
|
||||
passf4(idot, l1, a, offa, ch, 0, iw, isign);
|
||||
}
|
||||
break;
|
||||
case 2:
|
||||
if(inScratch)
|
||||
{
|
||||
passf2(idot, l1, ch, 0, a, offa, iw, isign);
|
||||
}
|
||||
else
|
||||
{
|
||||
passf2(idot, l1, a, offa, ch, 0, iw, isign);
|
||||
}
|
||||
break;
|
||||
case 3:
|
||||
if(inScratch)
|
||||
{
|
||||
passf3(idot, l1, ch, 0, a, offa, iw, isign);
|
||||
}
|
||||
else
|
||||
{
|
||||
passf3(idot, l1, a, offa, ch, 0, iw, isign);
|
||||
}
|
||||
break;
|
||||
case 5:
|
||||
if(inScratch)
|
||||
{
|
||||
passf5(idot, l1, ch, 0, a, offa, iw, isign);
|
||||
}
|
||||
else
|
||||
{
|
||||
passf5(idot, l1, a, offa, ch, 0, iw, isign);
|
||||
}
|
||||
break;
|
||||
default:
|
||||
throw new IllegalStateException("Unsupported radix: " + factor);
|
||||
}
|
||||
|
||||
inScratch = !inScratch;
|
||||
l1 = l2;
|
||||
iw += (factor - 1) * idot;
|
||||
}
|
||||
|
||||
if(inScratch)
|
||||
{
|
||||
System.arraycopy(ch, 0, a, offa, twon);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Radix 2 butterfly, ported from JTransforms passf2().
|
||||
*/
|
||||
private void passf2(final int ido, final int l1, final float[] in, final int in_off, final float[] out,
|
||||
final int out_off, final int offset, final int isign)
|
||||
{
|
||||
final float[] wtable = mTwiddles;
|
||||
int iw1 = offset;
|
||||
int idx = ido * l1;
|
||||
|
||||
if(ido <= 2)
|
||||
{
|
||||
for(int k = 0; k < l1; k++)
|
||||
{
|
||||
int idx0 = k * ido;
|
||||
int iidx1 = in_off + 2 * idx0;
|
||||
int iidx2 = iidx1 + ido;
|
||||
float a1r = in[iidx1];
|
||||
float a1i = in[iidx1 + 1];
|
||||
float a2r = in[iidx2];
|
||||
float a2i = in[iidx2 + 1];
|
||||
|
||||
int oidx1 = out_off + idx0;
|
||||
int oidx2 = oidx1 + idx;
|
||||
out[oidx1] = a1r + a2r;
|
||||
out[oidx1 + 1] = a1i + a2i;
|
||||
out[oidx2] = a1r - a2r;
|
||||
out[oidx2 + 1] = a1i - a2i;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
for(int k = 0; k < l1; k++)
|
||||
{
|
||||
for(int i = 0; i < ido - 1; i += 2)
|
||||
{
|
||||
int idx0 = k * ido;
|
||||
int iidx1 = in_off + i + 2 * idx0;
|
||||
int iidx2 = iidx1 + ido;
|
||||
float i1r = in[iidx1];
|
||||
float i1i = in[iidx1 + 1];
|
||||
float i2r = in[iidx2];
|
||||
float i2i = in[iidx2 + 1];
|
||||
|
||||
int widx1 = i + iw1;
|
||||
float w1r = wtable[widx1];
|
||||
float w1i = isign * wtable[widx1 + 1];
|
||||
|
||||
float t1r = i1r - i2r;
|
||||
float t1i = i1i - i2i;
|
||||
|
||||
int oidx1 = out_off + i + idx0;
|
||||
int oidx2 = oidx1 + idx;
|
||||
out[oidx1] = i1r + i2r;
|
||||
out[oidx1 + 1] = i1i + i2i;
|
||||
out[oidx2] = w1r * t1r - w1i * t1i;
|
||||
out[oidx2 + 1] = w1r * t1i + w1i * t1r;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Radix 3 butterfly, ported from JTransforms passf3().
|
||||
*/
|
||||
private void passf3(final int ido, final int l1, final float[] in, final int in_off, final float[] out,
|
||||
final int out_off, final int offset, final int isign)
|
||||
{
|
||||
final float taur = -0.5f;
|
||||
final float taui = 0.866025403784438707610604524234076962f;
|
||||
final float[] wtable = mTwiddles;
|
||||
int iw1 = offset;
|
||||
int iw2 = iw1 + ido;
|
||||
final int idxt = l1 * ido;
|
||||
|
||||
if(ido == 2)
|
||||
{
|
||||
for(int k = 1; k <= l1; k++)
|
||||
{
|
||||
int iidx1 = in_off + (3 * k - 2) * ido;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx1 - ido;
|
||||
float i1r = in[iidx1];
|
||||
float i1i = in[iidx1 + 1];
|
||||
float i2r = in[iidx2];
|
||||
float i2i = in[iidx2 + 1];
|
||||
float i3r = in[iidx3];
|
||||
float i3i = in[iidx3 + 1];
|
||||
|
||||
float tr2 = i1r + i2r;
|
||||
float cr2 = i3r + taur * tr2;
|
||||
float ti2 = i1i + i2i;
|
||||
float ci2 = i3i + taur * ti2;
|
||||
float cr3 = isign * taui * (i1r - i2r);
|
||||
float ci3 = isign * taui * (i1i - i2i);
|
||||
|
||||
int oidx1 = out_off + (k - 1) * ido;
|
||||
int oidx2 = oidx1 + idxt;
|
||||
int oidx3 = oidx2 + idxt;
|
||||
out[oidx1] = i3r + tr2;
|
||||
out[oidx1 + 1] = i3i + ti2;
|
||||
out[oidx2] = cr2 - ci3;
|
||||
out[oidx2 + 1] = ci2 + cr3;
|
||||
out[oidx3] = cr2 + ci3;
|
||||
out[oidx3 + 1] = ci2 - cr3;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
for(int k = 1; k <= l1; k++)
|
||||
{
|
||||
int idx1 = in_off + (3 * k - 2) * ido;
|
||||
int idx2 = out_off + (k - 1) * ido;
|
||||
|
||||
for(int i = 0; i < ido - 1; i += 2)
|
||||
{
|
||||
int iidx1 = i + idx1;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx1 - ido;
|
||||
float a1r = in[iidx1];
|
||||
float a1i = in[iidx1 + 1];
|
||||
float a2r = in[iidx2];
|
||||
float a2i = in[iidx2 + 1];
|
||||
float a3r = in[iidx3];
|
||||
float a3i = in[iidx3 + 1];
|
||||
|
||||
float tr2 = a1r + a2r;
|
||||
float cr2 = a3r + taur * tr2;
|
||||
float ti2 = a1i + a2i;
|
||||
float ci2 = a3i + taur * ti2;
|
||||
float cr3 = isign * taui * (a1r - a2r);
|
||||
float ci3 = isign * taui * (a1i - a2i);
|
||||
float dr2 = cr2 - ci3;
|
||||
float dr3 = cr2 + ci3;
|
||||
float di2 = ci2 + cr3;
|
||||
float di3 = ci2 - cr3;
|
||||
|
||||
int widx1 = i + iw1;
|
||||
int widx2 = i + iw2;
|
||||
float w1r = wtable[widx1];
|
||||
float w1i = isign * wtable[widx1 + 1];
|
||||
float w2r = wtable[widx2];
|
||||
float w2i = isign * wtable[widx2 + 1];
|
||||
|
||||
int oidx1 = i + idx2;
|
||||
int oidx2 = oidx1 + idxt;
|
||||
int oidx3 = oidx2 + idxt;
|
||||
out[oidx1] = a3r + tr2;
|
||||
out[oidx1 + 1] = a3i + ti2;
|
||||
out[oidx2] = w1r * dr2 - w1i * di2;
|
||||
out[oidx2 + 1] = w1r * di2 + w1i * dr2;
|
||||
out[oidx3] = w2r * dr3 - w2i * di3;
|
||||
out[oidx3 + 1] = w2r * di3 + w2i * dr3;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Radix 4 butterfly, ported from JTransforms passf4().
|
||||
*/
|
||||
private void passf4(final int ido, final int l1, final float[] in, final int in_off, final float[] out,
|
||||
final int out_off, final int offset, final int isign)
|
||||
{
|
||||
final float[] wtable = mTwiddles;
|
||||
int iw1 = offset;
|
||||
int iw2 = iw1 + ido;
|
||||
int iw3 = iw2 + ido;
|
||||
int idx0 = l1 * ido;
|
||||
|
||||
if(ido == 2)
|
||||
{
|
||||
for(int k = 0; k < l1; k++)
|
||||
{
|
||||
int idxt1 = k * ido;
|
||||
int iidx1 = in_off + 4 * idxt1 + 1;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx2 + ido;
|
||||
int iidx4 = iidx3 + ido;
|
||||
|
||||
float i1i = in[iidx1 - 1];
|
||||
float i1r = in[iidx1];
|
||||
float i2i = in[iidx2 - 1];
|
||||
float i2r = in[iidx2];
|
||||
float i3i = in[iidx3 - 1];
|
||||
float i3r = in[iidx3];
|
||||
float i4i = in[iidx4 - 1];
|
||||
float i4r = in[iidx4];
|
||||
|
||||
float ti1 = i1r - i3r;
|
||||
float ti2 = i1r + i3r;
|
||||
float tr4 = i4r - i2r;
|
||||
float ti3 = i2r + i4r;
|
||||
float tr1 = i1i - i3i;
|
||||
float tr2 = i1i + i3i;
|
||||
float ti4 = i2i - i4i;
|
||||
float tr3 = i2i + i4i;
|
||||
|
||||
int oidx1 = out_off + idxt1;
|
||||
int oidx2 = oidx1 + idx0;
|
||||
int oidx3 = oidx2 + idx0;
|
||||
int oidx4 = oidx3 + idx0;
|
||||
out[oidx1] = tr2 + tr3;
|
||||
out[oidx1 + 1] = ti2 + ti3;
|
||||
out[oidx2] = tr1 + isign * tr4;
|
||||
out[oidx2 + 1] = ti1 + isign * ti4;
|
||||
out[oidx3] = tr2 - tr3;
|
||||
out[oidx3 + 1] = ti2 - ti3;
|
||||
out[oidx4] = tr1 - isign * tr4;
|
||||
out[oidx4 + 1] = ti1 - isign * ti4;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
for(int k = 0; k < l1; k++)
|
||||
{
|
||||
int idx1 = k * ido;
|
||||
int idx2 = in_off + 1 + 4 * idx1;
|
||||
|
||||
for(int i = 0; i < ido - 1; i += 2)
|
||||
{
|
||||
int iidx1 = i + idx2;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx2 + ido;
|
||||
int iidx4 = iidx3 + ido;
|
||||
float i1i = in[iidx1 - 1];
|
||||
float i1r = in[iidx1];
|
||||
float i2i = in[iidx2 - 1];
|
||||
float i2r = in[iidx2];
|
||||
float i3i = in[iidx3 - 1];
|
||||
float i3r = in[iidx3];
|
||||
float i4i = in[iidx4 - 1];
|
||||
float i4r = in[iidx4];
|
||||
|
||||
float ti1 = i1r - i3r;
|
||||
float ti2 = i1r + i3r;
|
||||
float ti3 = i2r + i4r;
|
||||
float tr4 = i4r - i2r;
|
||||
float tr1 = i1i - i3i;
|
||||
float tr2 = i1i + i3i;
|
||||
float ti4 = i2i - i4i;
|
||||
float tr3 = i2i + i4i;
|
||||
float cr3 = tr2 - tr3;
|
||||
float ci3 = ti2 - ti3;
|
||||
float cr2 = tr1 + isign * tr4;
|
||||
float cr4 = tr1 - isign * tr4;
|
||||
float ci2 = ti1 + isign * ti4;
|
||||
float ci4 = ti1 - isign * ti4;
|
||||
|
||||
int widx1 = i + iw1;
|
||||
int widx2 = i + iw2;
|
||||
int widx3 = i + iw3;
|
||||
float w1r = wtable[widx1];
|
||||
float w1i = isign * wtable[widx1 + 1];
|
||||
float w2r = wtable[widx2];
|
||||
float w2i = isign * wtable[widx2 + 1];
|
||||
float w3r = wtable[widx3];
|
||||
float w3i = isign * wtable[widx3 + 1];
|
||||
|
||||
int oidx1 = out_off + i + idx1;
|
||||
int oidx2 = oidx1 + idx0;
|
||||
int oidx3 = oidx2 + idx0;
|
||||
int oidx4 = oidx3 + idx0;
|
||||
out[oidx1] = tr2 + tr3;
|
||||
out[oidx1 + 1] = ti2 + ti3;
|
||||
out[oidx2] = w1r * cr2 - w1i * ci2;
|
||||
out[oidx2 + 1] = w1r * ci2 + w1i * cr2;
|
||||
out[oidx3] = w2r * cr3 - w2i * ci3;
|
||||
out[oidx3 + 1] = w2r * ci3 + w2i * cr3;
|
||||
out[oidx4] = w3r * cr4 - w3i * ci4;
|
||||
out[oidx4 + 1] = w3r * ci4 + w3i * cr4;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Radix 5 butterfly, ported from JTransforms passf5().
|
||||
*/
|
||||
private void passf5(final int ido, final int l1, final float[] in, final int in_off, final float[] out,
|
||||
final int out_off, final int offset, final int isign)
|
||||
{
|
||||
final float tr11 = 0.309016994374947451262869435595348477f;
|
||||
final float ti11 = 0.951056516295153531181938433292089030f;
|
||||
final float tr12 = -0.809016994374947340240566973079694435f;
|
||||
final float ti12 = 0.587785252292473248125759255344746634f;
|
||||
final float[] wtable = mTwiddles;
|
||||
int iw1 = offset;
|
||||
int iw2 = iw1 + ido;
|
||||
int iw3 = iw2 + ido;
|
||||
int iw4 = iw3 + ido;
|
||||
int idx0 = l1 * ido;
|
||||
|
||||
if(ido == 2)
|
||||
{
|
||||
for(int k = 1; k <= l1; ++k)
|
||||
{
|
||||
int iidx1 = in_off + (5 * k - 4) * ido + 1;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx1 - ido;
|
||||
int iidx4 = iidx2 + ido;
|
||||
int iidx5 = iidx4 + ido;
|
||||
|
||||
float i1i = in[iidx1 - 1];
|
||||
float i1r = in[iidx1];
|
||||
float i2i = in[iidx2 - 1];
|
||||
float i2r = in[iidx2];
|
||||
float i3i = in[iidx3 - 1];
|
||||
float i3r = in[iidx3];
|
||||
float i4i = in[iidx4 - 1];
|
||||
float i4r = in[iidx4];
|
||||
float i5i = in[iidx5 - 1];
|
||||
float i5r = in[iidx5];
|
||||
|
||||
float ti5 = i1r - i5r;
|
||||
float ti2 = i1r + i5r;
|
||||
float ti4 = i2r - i4r;
|
||||
float ti3 = i2r + i4r;
|
||||
float tr5 = i1i - i5i;
|
||||
float tr2 = i1i + i5i;
|
||||
float tr4 = i2i - i4i;
|
||||
float tr3 = i2i + i4i;
|
||||
float cr2 = i3i + tr11 * tr2 + tr12 * tr3;
|
||||
float ci2 = i3r + tr11 * ti2 + tr12 * ti3;
|
||||
float cr3 = i3i + tr12 * tr2 + tr11 * tr3;
|
||||
float ci3 = i3r + tr12 * ti2 + tr11 * ti3;
|
||||
float cr5 = isign * (ti11 * tr5 + ti12 * tr4);
|
||||
float ci5 = isign * (ti11 * ti5 + ti12 * ti4);
|
||||
float cr4 = isign * (ti12 * tr5 - ti11 * tr4);
|
||||
float ci4 = isign * (ti12 * ti5 - ti11 * ti4);
|
||||
|
||||
int oidx1 = out_off + (k - 1) * ido;
|
||||
int oidx2 = oidx1 + idx0;
|
||||
int oidx3 = oidx2 + idx0;
|
||||
int oidx4 = oidx3 + idx0;
|
||||
int oidx5 = oidx4 + idx0;
|
||||
out[oidx1] = i3i + tr2 + tr3;
|
||||
out[oidx1 + 1] = i3r + ti2 + ti3;
|
||||
out[oidx2] = cr2 - ci5;
|
||||
out[oidx2 + 1] = ci2 + cr5;
|
||||
out[oidx3] = cr3 - ci4;
|
||||
out[oidx3 + 1] = ci3 + cr4;
|
||||
out[oidx4] = cr3 + ci4;
|
||||
out[oidx4 + 1] = ci3 - cr4;
|
||||
out[oidx5] = cr2 + ci5;
|
||||
out[oidx5 + 1] = ci2 - cr5;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
for(int k = 1; k <= l1; k++)
|
||||
{
|
||||
int idx1 = in_off + 1 + (k * 5 - 4) * ido;
|
||||
int idx2 = out_off + (k - 1) * ido;
|
||||
|
||||
for(int i = 0; i < ido - 1; i += 2)
|
||||
{
|
||||
int iidx1 = i + idx1;
|
||||
int iidx2 = iidx1 + ido;
|
||||
int iidx3 = iidx1 - ido;
|
||||
int iidx4 = iidx2 + ido;
|
||||
int iidx5 = iidx4 + ido;
|
||||
float i1i = in[iidx1 - 1];
|
||||
float i1r = in[iidx1];
|
||||
float i2i = in[iidx2 - 1];
|
||||
float i2r = in[iidx2];
|
||||
float i3i = in[iidx3 - 1];
|
||||
float i3r = in[iidx3];
|
||||
float i4i = in[iidx4 - 1];
|
||||
float i4r = in[iidx4];
|
||||
float i5i = in[iidx5 - 1];
|
||||
float i5r = in[iidx5];
|
||||
|
||||
float ti5 = i1r - i5r;
|
||||
float ti2 = i1r + i5r;
|
||||
float ti4 = i2r - i4r;
|
||||
float ti3 = i2r + i4r;
|
||||
float tr5 = i1i - i5i;
|
||||
float tr2 = i1i + i5i;
|
||||
float tr4 = i2i - i4i;
|
||||
float tr3 = i2i + i4i;
|
||||
float cr2 = i3i + tr11 * tr2 + tr12 * tr3;
|
||||
float ci2 = i3r + tr11 * ti2 + tr12 * ti3;
|
||||
float cr3 = i3i + tr12 * tr2 + tr11 * tr3;
|
||||
float ci3 = i3r + tr12 * ti2 + tr11 * ti3;
|
||||
float cr5 = isign * (ti11 * tr5 + ti12 * tr4);
|
||||
float ci5 = isign * (ti11 * ti5 + ti12 * ti4);
|
||||
float cr4 = isign * (ti12 * tr5 - ti11 * tr4);
|
||||
float ci4 = isign * (ti12 * ti5 - ti11 * ti4);
|
||||
float dr3 = cr3 - ci4;
|
||||
float dr4 = cr3 + ci4;
|
||||
float di3 = ci3 + cr4;
|
||||
float di4 = ci3 - cr4;
|
||||
float dr5 = cr2 + ci5;
|
||||
float dr2 = cr2 - ci5;
|
||||
float di5 = ci2 - cr5;
|
||||
float di2 = ci2 + cr5;
|
||||
|
||||
int widx1 = i + iw1;
|
||||
int widx2 = i + iw2;
|
||||
int widx3 = i + iw3;
|
||||
int widx4 = i + iw4;
|
||||
float w1r = wtable[widx1];
|
||||
float w1i = isign * wtable[widx1 + 1];
|
||||
float w2r = wtable[widx2];
|
||||
float w2i = isign * wtable[widx2 + 1];
|
||||
float w3r = wtable[widx3];
|
||||
float w3i = isign * wtable[widx3 + 1];
|
||||
float w4r = wtable[widx4];
|
||||
float w4i = isign * wtable[widx4 + 1];
|
||||
|
||||
int oidx1 = i + idx2;
|
||||
int oidx2 = oidx1 + idx0;
|
||||
int oidx3 = oidx2 + idx0;
|
||||
int oidx4 = oidx3 + idx0;
|
||||
int oidx5 = oidx4 + idx0;
|
||||
out[oidx1] = i3i + tr2 + tr3;
|
||||
out[oidx1 + 1] = i3r + ti2 + ti3;
|
||||
out[oidx2] = w1r * dr2 - w1i * di2;
|
||||
out[oidx2 + 1] = w1r * di2 + w1i * dr2;
|
||||
out[oidx3] = w2r * dr3 - w2i * di3;
|
||||
out[oidx3 + 1] = w2r * di3 + w2i * dr3;
|
||||
out[oidx4] = w3r * dr4 - w3i * di4;
|
||||
out[oidx4 + 1] = w3r * di4 + w3i * dr4;
|
||||
out[oidx5] = w4r * dr5 - w4i * di5;
|
||||
out[oidx5 + 1] = w4r * di5 + w4i * dr5;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
@@ -18,6 +18,7 @@
|
||||
*/
|
||||
package io.github.dsheirer.dsp.filter.channelizer;
|
||||
|
||||
import io.github.dsheirer.dsp.fft.MixedRadixComplexFFT;
|
||||
import io.github.dsheirer.dsp.filter.FilterFactory;
|
||||
import io.github.dsheirer.dsp.filter.design.FilterDesignException;
|
||||
import io.github.dsheirer.sample.complex.InterleavedComplexSamples;
|
||||
@@ -27,7 +28,6 @@ import java.util.Arrays;
|
||||
import java.util.Queue;
|
||||
import java.util.concurrent.ArrayBlockingQueue;
|
||||
import org.apache.commons.math3.util.FastMath;
|
||||
import org.jtransforms.fft.FloatFFT_1D;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
@@ -85,7 +85,8 @@ public class ComplexPolyphaseChannelizerM2 extends AbstractComplexPolyphaseChann
|
||||
|
||||
//Sized to process 40 times per second
|
||||
private IFFTProcessorDispatcher mIFFTProcessorDispatcher = new IFFTProcessorDispatcher(25);
|
||||
private FloatFFT_1D mFFT;
|
||||
//Allocation-free IFFT. Only used by the IFFT processor dispatcher thread since it reuses a scratch buffer.
|
||||
private MixedRadixComplexFFT mFFT;
|
||||
private ChannelDFT mChannelDFT;
|
||||
private float[] mInlineSamples;
|
||||
private float[] mInlineFilter;
|
||||
@@ -453,7 +454,7 @@ public class ComplexPolyphaseChannelizerM2 extends AbstractComplexPolyphaseChann
|
||||
private void init(float[] coefficients)
|
||||
{
|
||||
int channelCount = getChannelCount();
|
||||
mFFT = new FloatFFT_1D(channelCount);
|
||||
mFFT = new MixedRadixComplexFFT(channelCount);
|
||||
mChannelDFT = ChannelDFTFactory.getChannelDFT(channelCount);
|
||||
int bufferLength = getSubChannelCount() * mTapsPerChannel;
|
||||
mSamplesPerBlock = channelCount; //Same as subChannelCount / 2
|
||||
@@ -505,7 +506,7 @@ public class ComplexPolyphaseChannelizerM2 extends AbstractComplexPolyphaseChann
|
||||
for(int offset = 0; offset < samples.length; offset += blockLength)
|
||||
{
|
||||
//Rotate each of the channels to the correct phase using the IFFT
|
||||
mFFT.complexInverse(samples, offset, true);
|
||||
mFFT.inverse(samples, offset, true);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user