de.gsi.math

Class ArrayMath

java.lang.Object

de.gsi.math.ArrayMath

public final class ArrayMath
extends Object

some double array convenience methods

Author:

rstein

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ArrayMath.FilterType

Constructor Summary

Constructors

Constructor and Description
ArrayMath()

Method Summary

Modifier and Type	Method and Description
static double[]	add(double[] in, double add)
static double[]	add(double[] in, double[] add)
static double[]	addInPlace(double[] in, double value)
static double[]	addInPlace(double[] in, double[] value)
static double[]	calculateFilterParameters(double cutoffFraction, ArrayMath.FilterType filterType, double rippleP, double numberOfPoles, int iteration) calculate 2nd-order filter with Butterworth (rippleP=0) or Chebychev filter response (rippleP>0) N.B.
static double[]	decibel(double[] in)
static double[]	decibelInPlace(double[] in)
static double[]	divide(double[] in, double divisor)
static double[]	divide(double[] in, double[] divisor)
static double[]	divideInPlace(double[] in, double divisor)
static double[]	divideInPlace(double[] in, double[] divisor)
static double[]	filterSignal(double[] signal, double cutoffFraction, double filterOrder, ArrayMath.FilterType filterType, double ripplePercent) filter from: "The Scientist and Engineer's Guide to DSP" Chapter 20
static double[]	multiply(double[] in, double multiplicator)
static double[]	multiply(double[] in, double[] multiplicator)
static double[]	multiplyInPlace(double[] in, double multiplicator)
static double[]	multiplyInPlace(double[] in, double[] multiplicator)
static double[]	sqr(double[] in)
static double[]	sqrInPlace(double[] in)
static double[]	sqrt(double[] in)
static double[]	sqrtInPlace(double[] in)
static double[]	subtract(double[] in, double value)
static double[]	subtract(double[] in, double[] value)
static double[]	subtractInPlace(double[] in, double value)
static double[]	subtractInPlace(double[] in, double[] value)
static double[]	tenLog10(double[] in)
static double[]	tenLog10InPlace(double[] in)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ArrayMath

public ArrayMath()

Method Detail

add

public static double[] add(double[] in,
                           double add)

add

public static double[] add(double[] in,
                           double[] add)

addInPlace

public static double[] addInPlace(double[] in,
                                  double value)

addInPlace

public static double[] addInPlace(double[] in,
                                  double[] value)

calculateFilterParameters

public static double[] calculateFilterParameters(double cutoffFraction,
                                                 ArrayMath.FilterType filterType,
                                                 double rippleP,
                                                 double numberOfPoles,
                                                 int iteration)

calculate 2nd-order filter with Butterworth (rippleP=0) or Chebychev filter response (rippleP>0) N.B. numerically validated against data set examples in Table 20-6 http://www.dspguide.com/ch20/4.htm

Parameters:

cutoffFraction - fractional cut-off

filterType - LOW_PASS or HIGH_PASS

rippleP - >0 -> Chebychev design-ripple in percent in the pass-band

numberOfPoles - number of poles (if combined with 2*n filter stages)

iteration - (whether this is the i-th filter in the chain)

Returns:

array of [A0, A1, A2, B1, B2]

decibel

public static double[] decibel(double[] in)

decibelInPlace

public static double[] decibelInPlace(double[] in)

divide

public static double[] divide(double[] in,
                              double divisor)

divide

public static double[] divide(double[] in,
                              double[] divisor)

divideInPlace

public static double[] divideInPlace(double[] in,
                                     double divisor)

divideInPlace

public static double[] divideInPlace(double[] in,
                                     double[] divisor)

filterSignal

public static double[] filterSignal(double[] signal,
                                    double cutoffFraction,
                                    double filterOrder,
                                    ArrayMath.FilterType filterType,
                                    double ripplePercent)

filter from: "The Scientist and Engineer's Guide to DSP" Chapter 20

Parameters:

signal - input signal

cutoffFraction - cutoffFreq must be smaller than half the samplerate

filterOrder - can be between 2 and 20

filterType - 0: lowPass 1: highPass

ripplePercent - ripplePercent is amount of ripple in Chebyshev filter (0-29) (ripplePercent == 0 -> Butterworth)

Returns:

filtered output signal

multiply

public static double[] multiply(double[] in,
                                double multiplicator)

multiply

public static double[] multiply(double[] in,
                                double[] multiplicator)

multiplyInPlace

public static double[] multiplyInPlace(double[] in,
                                       double multiplicator)

multiplyInPlace

public static double[] multiplyInPlace(double[] in,
                                       double[] multiplicator)

sqr

public static double[] sqr(double[] in)

sqrInPlace

public static double[] sqrInPlace(double[] in)

sqrt

public static double[] sqrt(double[] in)

sqrtInPlace

public static double[] sqrtInPlace(double[] in)

subtract

public static double[] subtract(double[] in,
                                double value)

subtract

public static double[] subtract(double[] in,
                                double[] value)

subtractInPlace

public static double[] subtractInPlace(double[] in,
                                       double value)

subtractInPlace

public static double[] subtractInPlace(double[] in,
                                       double[] value)

tenLog10

public static double[] tenLog10(double[] in)

tenLog10InPlace

public static double[] tenLog10InPlace(double[] in)