Java Code Examples for org.apache.commons.math3.util.ArithmeticUtils#isPowerOfTwo()
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org.apache.commons.math3.util.ArithmeticUtils#isPowerOfTwo() .
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Example 1
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 2
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 3
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 4
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 5
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 6
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 7
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 8
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 9
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 10
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 11
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 12
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 13
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 14
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
Example 15
| Source File: FastSineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FST algorithm (including inverse). The first element of the
* data set is required to be {@code 0}.
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two, or the first element of the data array is not zero
*/
protected double[] fst(double[] f) throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
if (!ArithmeticUtils.isPowerOfTwo(f.length)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_CONSIDER_PADDING,
Integer.valueOf(f.length));
}
if (f[0] != 0.0) {
throw new MathIllegalArgumentException(
LocalizedFormats.FIRST_ELEMENT_NOT_ZERO,
Double.valueOf(f[0]));
}
final int n = f.length;
if (n == 1) { // trivial case
transformed[0] = 0.0;
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.0;
x[n >> 1] = 2.0 * f[n >> 1];
for (int i = 1; i < (n >> 1); i++) {
final double a = FastMath.sin(i * FastMath.PI / n) * (f[i] + f[n - i]);
final double b = 0.5 * (f[i] - f[n - i]);
x[i] = a + b;
x[n - i] = a - b;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FST result for the original array
transformed[0] = 0.0;
transformed[1] = 0.5 * y[0].getReal();
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = -y[i].getImaginary();
transformed[2 * i + 1] = y[i].getReal() + transformed[2 * i - 1];
}
return transformed;
}
Example 16
| Source File: FastCosineTransformer.java From astor with GNU General Public License v2.0 | 4 votes |
|
/**
* Perform the FCT algorithm (including inverse).
*
* @param f the real data array to be transformed
* @return the real transformed array
* @throws MathIllegalArgumentException if the length of the data array is
* not a power of two plus one
*/
protected double[] fct(double[] f)
throws MathIllegalArgumentException {
final double[] transformed = new double[f.length];
final int n = f.length - 1;
if (!ArithmeticUtils.isPowerOfTwo(n)) {
throw new MathIllegalArgumentException(
LocalizedFormats.NOT_POWER_OF_TWO_PLUS_ONE,
Integer.valueOf(f.length));
}
if (n == 1) { // trivial case
transformed[0] = 0.5 * (f[0] + f[1]);
transformed[1] = 0.5 * (f[0] - f[1]);
return transformed;
}
// construct a new array and perform FFT on it
final double[] x = new double[n];
x[0] = 0.5 * (f[0] + f[n]);
x[n >> 1] = f[n >> 1];
// temporary variable for transformed[1]
double t1 = 0.5 * (f[0] - f[n]);
for (int i = 1; i < (n >> 1); i++) {
final double a = 0.5 * (f[i] + f[n - i]);
final double b = FastMath.sin(i * FastMath.PI / n) * (f[i] - f[n - i]);
final double c = FastMath.cos(i * FastMath.PI / n) * (f[i] - f[n - i]);
x[i] = a - b;
x[n - i] = a + b;
t1 += c;
}
FastFourierTransformer transformer;
transformer = new FastFourierTransformer(DftNormalization.STANDARD);
Complex[] y = transformer.transform(x, TransformType.FORWARD);
// reconstruct the FCT result for the original array
transformed[0] = y[0].getReal();
transformed[1] = t1;
for (int i = 1; i < (n >> 1); i++) {
transformed[2 * i] = y[i].getReal();
transformed[2 * i + 1] = transformed[2 * i - 1] - y[i].getImaginary();
}
transformed[n] = y[n >> 1].getReal();
return transformed;
}
