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org.nd4j.linalg.api.ops.impl.transforms.VectorFFT Maven / Gradle / Ivy
/*-
*
* * Copyright 2015 Skymind,Inc.
* *
* * Licensed under the Apache License, Version 2.0 (the "License");
* * you may not use this file except in compliance with the License.
* * You may obtain a copy of the License at
* *
* * http://www.apache.org/licenses/LICENSE-2.0
* *
* * Unless required by applicable law or agreed to in writing, software
* * distributed under the License is distributed on an "AS IS" BASIS,
* * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* * See the License for the specific language governing permissions and
* * limitations under the License.
*
*
*/
package org.nd4j.linalg.api.ops.impl.transforms;
import org.apache.commons.math3.util.FastMath;
import org.nd4j.linalg.api.complex.IComplexNDArray;
import org.nd4j.linalg.api.complex.IComplexNumber;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.api.ops.BaseTransformOp;
import org.nd4j.linalg.api.ops.Op;
import org.nd4j.linalg.factory.Nd4j;
import org.nd4j.linalg.util.ComplexNDArrayUtil;
import static org.nd4j.linalg.ops.transforms.Transforms.exp;
/**
* Encapsulated vector operation
*
* @author Adam Gibson
*/
public class VectorFFT extends BaseTransformOp {
protected int fftLength;
private int originalN = -1;
protected boolean executed = false;
public VectorFFT() {}
public VectorFFT(INDArray x, INDArray z, int fftLength) {
super(x, z);
this.fftLength = fftLength;
this.n = fftLength;
exec();
}
public VectorFFT(INDArray x, INDArray z, long n, int fftLength) {
super(x, z, n);
this.fftLength = fftLength;
this.n = fftLength;
exec();
}
public VectorFFT(INDArray x, INDArray y, INDArray z, long n, int fftLength) {
super(x, y, z, n);
this.z = z;
this.fftLength = fftLength;
exec();
}
public VectorFFT(INDArray x, int fftLength) {
super(x);
this.z = x;
this.fftLength = fftLength;
exec();
}
public VectorFFT(INDArray x) {
this(x, x.length());
}
@Override
public int opNum() {
return 1;
}
@Override
public String name() {
return "fft";
}
@Override
public IComplexNumber op(IComplexNumber origin, double other) {
return origin;
}
@Override
public IComplexNumber op(IComplexNumber origin, float other) {
return origin;
}
@Override
public IComplexNumber op(IComplexNumber origin, IComplexNumber other) {
return origin;
}
@Override
public float op(float origin, float other) {
return origin;
}
@Override
public double op(double origin, double other) {
return origin;
}
@Override
public double op(double origin) {
return origin;
}
@Override
public float op(float origin) {
return origin;
}
@Override
public IComplexNumber op(IComplexNumber origin) {
return origin;
}
@Override
public Op opForDimension(int index, int dimension) {
INDArray xAlongDimension = x.vectorAlongDimension(index, dimension);
if (y() != null)
return new VectorFFT(xAlongDimension, y.vectorAlongDimension(index, dimension),
z.vectorAlongDimension(index, dimension), xAlongDimension.length(), fftLength);
else
return new VectorFFT(xAlongDimension, z.vectorAlongDimension(index, dimension), xAlongDimension.length(),
fftLength);
}
@Override
public Op opForDimension(int index, int... dimension) {
INDArray xAlongDimension = x.tensorAlongDimension(index, dimension);
if (y() != null)
return new VectorFFT(xAlongDimension, y.tensorAlongDimension(index, dimension),
z.tensorAlongDimension(index, dimension), xAlongDimension.length(), fftLength);
else
return new VectorFFT(xAlongDimension, z.tensorAlongDimension(index, dimension), xAlongDimension.length(),
fftLength);
}
@Override
public void exec() {
if (!x.isVector())
return;
if (executed)
return;
executed = true;
double len = fftLength;
IComplexNDArray ret = x instanceof IComplexNDArray ? (IComplexNDArray) x : Nd4j.createComplex(x);
int desiredElementsAlongDimension = ret.length();
if (len > desiredElementsAlongDimension) {
ret = ComplexNDArrayUtil.padWithZeros(ret, new int[] {fftLength});
} else if (len < desiredElementsAlongDimension) {
ret = ComplexNDArrayUtil.truncate(ret, fftLength, 0);
}
IComplexNumber c2 = Nd4j.createDouble(0, -2).muli(FastMath.PI);
//row vector
INDArray n2 = Nd4j.arange(0, this.fftLength).reshape(1, this.fftLength);
//column vector
INDArray k = n2.reshape(n2.length(), 1);
INDArray kTimesN = k.mmul(n2);
//here
IComplexNDArray c1 = kTimesN.muli(c2);
c1.divi(len);
IComplexNDArray M = (IComplexNDArray) exp(c1);
IComplexNDArray reshaped = ret.reshape(new int[] {1, ret.length()});
IComplexNDArray matrix = reshaped.mmul(M);
if (originalN > 0)
matrix = ComplexNDArrayUtil.truncate(matrix, originalN, 0);
//completely pass through
this.x = matrix;
this.z = matrix;
}
@Override
public boolean isPassThrough() {
return true;
}
@Override
public void setX(INDArray x) {
this.x = x;
this.fftLength = x.length();
this.n = x.length();
executed = false;
}
@Override
public void setZ(INDArray z) {
this.z = z;
this.fftLength = z.length();
this.n = fftLength;
executed = false;
}
@Override
public void setY(INDArray y) {
this.y = y;
}
}