triana.types.util

Class FlatArray

java.lang.Object

triana.types.util.FlatArray

All Implemented Interfaces:

java.io.Serializable

public class FlatArray
extends java.lang.Object
implements java.io.Serializable

FlatArray holds the contents of a multi-dimensional array that has been flattened, i.e. whose elements have been mapped onto a one-dimensional array. It contains the one-dimensional array, an integer array holding the lengths of the original array dimensions, and the name of the type of the component of the flattened array. It provides a method to reconstruct the original array from the flattened array and lengths. Arrays can have elements of any type.

Arrays can be partially flattened, so that the highest few dimensions are mapped onto a single dimension but the remaining dimensions are kept as array elements of flattened array.

FlatArray also contains a large number of class methods as utilities for the manipulation of arrays using the flattening technique. These are extensively used in GraphType.

See Also:

GraphType, Serialized Form

Constructor Summary

Constructors

Constructor and Description
FlatArray() Constructs an empty FlatArray.
FlatArray(java.lang.Object o) Constructs a FlatArray from the given array.
FlatArray(java.lang.Object o, int depth) Constructs a FlatArray from the given array by flattening all the dimensions up to argument depth.
FlatArray(java.lang.Object o, int[] l) Constructs a FlatArray from the given flattened array and the given array of integers.

Method Summary

Methods

Modifier and Type	Method and Description
static java.lang.Object	addArrays(java.lang.Object a1, java.lang.Object a2) Class method that adds the elements of the two given arrays.
static java.lang.Object	convertArrayElements(java.lang.Object o, java.lang.Class outClass) Class method that converts the given input array to an array whose elements are of the type given by the Class in the second argument.
static double[]	convertToFullSpectrum(double[] input, int full, boolean onesided, boolean realpart, boolean narrowband, int low) Class method that converts takes the given spectral data array, which can be one-sided and/or narrow-band, and which is assumed to be stored according to the Triana spectral data model, and returns the associated two-sided full-bandwidth data array.
static double[]	convertToNarrowBand(double[] fullArray, boolean oneSide, int low, int high) Class method that converts a full-bandwidth spectrum to a narrow-band spectrum.
static double[]	convertToOneSided(double[] twoSide, int full, boolean narrowband, boolean containsZeroFrequency) Class method that takes the given array, assumed to be a two-sided spectrum (either the real or imaginary part) and returns the associated one-sided spectrum.
static java.lang.Object	divideArrays(java.lang.Object a1, java.lang.Object a2) Class method that divides the individual elements of two arrays.
static java.util.ArrayList	divideArrays(java.lang.Object a1r, java.lang.Object a1i, java.lang.Object a2r, java.lang.Object a2i) Class method that divides the individual elements of two complex arrays, whose real and imaginary parts are the four given arrays.
static boolean	equalArrays(java.lang.Object a1, java.lang.Object a2) Class method that tests the elements of the two given arrays.
static java.lang.String	findArrayComponentName(java.lang.Object o, int depth) Class method to find the name of the type of the component of an array down to a certain depth.
static int[]	findArrayDimensionLengths(java.lang.Object o) Class method finds the size of each dimension of a multi-dimensional array.
static int[]	findArrayDimensionLengths(java.lang.Object o, int depth) Class method finds the size of each dimension of a multi-dimensional array down to a certain depth.
static int	findNumberOfDimensions(java.lang.Object o) Class method finds the number of dimensions of a multi-dimensional array.
java.lang.String	getComponentName() Returns the name of the type of the components of the flattened array.
java.lang.Object	getFlatArray() Returns the array that holds the flattened data.
int	getFlatLength() Returns the length of the flattened array, which is the total number of elements in the original array.
int[]	getLengths() Returns the int[] that contains the lengths of the dimensions of the original array.
static boolean	incrementArray(java.lang.Object o, double s) Class method that adds the given real number to the given data array and returns a boolean true value to indicate success.
static boolean	incrementArray(java.lang.Object or, java.lang.Object oi, double sr, double si) Class method that adds the given complex number (supplied as two doubles in the last two arguments) to the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) and returns a boolean true value to indicate success.
static java.util.ArrayList	incrementCopyOfArray(java.lang.Object or, java.lang.Object oi, double sr, double si) Class method that adds the given complex number (supplied as two doubles in the last two arguments) to the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) and returns an ArrayList holding the real and imaginary parts of the results as new arrays of doubles of the same dimensionality as the given arrays.
static void	initializeArray(java.lang.Object a) Class method that sets the elements of the given array to zero.
static boolean	isArithmeticArray(java.lang.Object o) Class method that returns true if the given multi-dimensional array contains these primitive Java data types at its lowest level: byte, short, int, long, float, or double.
static boolean	isPrimitiveArray(java.lang.Object o) Class method that returns true if the given multi-dimensional array is an array of primitive Java data types at its lowest level.
static double	maxArray(java.lang.Object in) Class method maxArray returns a double containing the maximum value of all the elements of the given array, if its elements are of an arithmetic data type, as determined by method isArithmeticArray.
static double	minArray(java.lang.Object in) Class method that returns a double containing the minimum value of all the elements of the given array, if its elements are of an arithmetic data type, as determined by method isArithmeticArray.
static java.lang.Object	multiArrayCopy(java.lang.Object o) Class method that copies an arbitrary multi-dimensional array to another array of the same dimensions.
static java.lang.Object	multiArrayImitate(java.lang.Object o) Class method that creates a new array with the same dimensionality and component types as the given arbitrary multi-dimensional array.
static java.lang.Object	multiplyArrays(java.lang.Object a1, java.lang.Object a2) Class method that multiplies the individual elements of the two given arrays.
static java.util.ArrayList	multiplyArrays(java.lang.Object a1r, java.lang.Object a1i, java.lang.Object a2r, java.lang.Object a2i) Class method that multiplies the individual elements of two complex arrays, whose real and imaginary parts are the four given arrays.
java.lang.Object	restoreArray() Creates an array of the dimensionality given by lengths and containing the data held in flatArray,/i>.
java.lang.Object	restoreArray(boolean copy) Returns an array of the dimensionality given by lengths and containing the data held in flatArray.
static boolean	scaleArray(java.lang.Object o, double s) Class method that multiplies the given real data array by the given real number and returns a boolean true value to indicate success.
static boolean	scaleArray(java.lang.Object or, java.lang.Object oi, double sr, double si) Class method that multiplies the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) by the given complex number (supplied as two doubles in the last two arguments) and returns a boolean true value to indicate success.
static java.util.ArrayList	scaleCopyOfArray(java.lang.Object or, java.lang.Object oi, double sr, double si) Class method that multiplies the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) by the given complex number (supplied as two doubles in the last two arguments) and returns an ArrayList holding the real and imaginary parts of the results as new arrays of doubles of the same dimensionality as the given arrays.
void	setComponentName(java.lang.String newComponentName) Sets the name of the type of the component of the flat array.
void	setFlatArray(java.lang.Object newArray) Sets the Array that holds the flattened data.
void	setLengths(int[] newLengths) Sets the int[] that holds the lengths of the original dimensions.
static boolean	similarArrays(java.lang.Object a1, java.lang.Object a2) Class method that tests to see if the given arrays are of a similar type: both Objects are indeed arrays, they have the same dimensionality, and their sizes in the different dimensions are the same.
static java.lang.Object	subtractArrays(java.lang.Object a1, java.lang.Object a2) Class method that subtracts the elements of the second given array from those of the first.
static int	testConjugateSymmetry(double[] xr, double[] xi) Class method to test whether a spectral data set has the symmetry property that will result in its inverse transform being pure real or pure imaginary.
static java.lang.Object	toByteArray(java.lang.Object o) Class method that converts a given input array to an array of bytes.
static java.lang.Object	toDoubleArray(java.lang.Object o) Class method that converts a given input array to an array of doubles.
static java.lang.Object	toFloatArray(java.lang.Object o) Class method that converts a given input array to an array of floats.
static java.lang.Object	toIntArray(java.lang.Object o) Class method that converts a given input array to an array of ints.
static java.lang.Object	toLongArray(java.lang.Object o) Class method that converts a given input array to an array of longs.
static java.lang.Object	toShortArray(java.lang.Object o) Class method that converts a given input array to an array of shorts.

Methods inherited from class java.lang.Object

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

Constructor Detail

FlatArray

public FlatArray()

Constructs an empty FlatArray.

FlatArray

public FlatArray(java.lang.Object o)

Constructs a FlatArray from the given array. All dimensions higher than one are flattened. If the input object is a 1-dimensional array then it is not processed, and array lengths has only one element. If the input object is not an array, then FlatArray creates a 1-dimensional array with the object as the single element and sets the single element of lengths to 1.

Parameters:

o - The array to be fully flattened

FlatArray

public FlatArray(java.lang.Object o,
         int depth)

Constructs a FlatArray from the given array by flattening all the dimensions up to argument depth. The array lengths contains the lengths of only the dimensions to be flattened. If the input object is a 1-dimensional array then it is not processed, and lengths has only one element. If the input object has fewer dimensions than depth, then it is fully flattened. If the input object is not an array, then FlatArray creates a 1-dimensional array with the object as the single element and sets the single element of lengths to 1.

Parameters:

o - The array to be flattened

depth - The last dimension to be flattened, counting from 0

FlatArray

public FlatArray(java.lang.Object o,
         int[] l)

Constructs a FlatArray from the given flattened array and the given array of integers. The user must check that the integer array is consistent with the flattened array, in that the product of its elements equals the length of the array.

Parameters:

o - The flattened array

l - The lengths of the dimensions of the corresponding unflattened array

Method Detail

findNumberOfDimensions

public static int findNumberOfDimensions(java.lang.Object o)

Class method finds the number of dimensions of a multi-dimensional array. If the object argument is not an array, the method returns 0.

Parameters:

o - The multi-dimensional array to be examined

Returns:

The number of dimensions of the given array

findArrayDimensionLengths

public static int[] findArrayDimensionLengths(java.lang.Object o)

Class method finds the size of each dimension of a multi-dimensional array. It returns an int[] that contains the sizes of the dimensions. The argument can be any Object, but if the argument is not an array, then the method returns null.

Note that the method only looks at the length of the first row in each dimension, so it will not give sensible information unless the multi-dimensional array is "rectangular", ie unless all the rows in a given dimension have the same length.

Parameters:

o - The input (multi-dimensional) array

Returns:

The lengths of the dimensions

findArrayDimensionLengths

public static int[] findArrayDimensionLengths(java.lang.Object o,
                              int depth)

Class method finds the size of each dimension of a multi-dimensional array down to a certain depth. It returns an int[] that contains the sizes of the dimensions. The argument can be any Object, but if the argument is not an array, then the method returns null. If the given depth is actually larger than the number of dimensions of the array, depth is reset to the number of dimensions.

Note that the method only looks at the length of the first row in each dimension, so it will not give sensible information unless the multi-dimensional array is "rectangular", ie unless all the rows in a given dimension have the same length.

Parameters:

o - The input (multi-dimensional) array

depth - The number of dimensions whose size is desired

Returns:

The lengths of the dimensions down to depth

findArrayComponentName

public static java.lang.String findArrayComponentName(java.lang.Object o,
                                      int depth)

Class method to find the name of the type of the component of an array down to a certain depth. Since Java multi-dimensional arrays are stored as arrays of arrays, one can ask for the component type at any level in the hierarchy. In Triana data for dependent variables, the data arrays may have more dimensions than the number of independent variables. If so, the extra dimensions are regarded as the elementary components of the data at the points in independent variable space. Thus, a vector field in two dimensions is represented by a two-dimensional array of vectors, and so is stored as a three-dimensional array. The present method allows the user to specify the depth in this hierarchical array in which the class of the remaining levels is to be found. The parameter depth is the number of dimensions that should be stripped away before asking for the component type. Thus, depth = 0 returns the type of the elements of the highest dimension of the array. To discover the component type in the Triana sense, use depth = independentVariables - 1. If the array has fewer dimensions than depth - 1, the method returns null. If the argument is not an array, the method returns its type name.

Parameters:

o - The data array to be examined

depth - The depth at which one wants the component type

Returns:

The component type name

multiArrayImitate

public static java.lang.Object multiArrayImitate(java.lang.Object o)

Class method that creates a new array with the same dimensionality and component types as the given arbitrary multi-dimensional array. Arrays with primitive components are returned with with default initialization; arrays with other object components are returned with null initializations.

The argument can be any Object, but if the argument is not an array, then the method returns null.

Note that the method only looks at the length of the first row of the input array in each dimension, so it will not give a correct imitation of the input array unless the multi-dimensional array is "rectangular", ie unless all the rows in a given dimension have the same length.

Parameters:

o - The input (multi-dimensional) array

Returns:

An imitation of the input, i.e. an empty array of the same type

multiArrayCopy

public static java.lang.Object multiArrayCopy(java.lang.Object o)

Class method that copies an arbitrary multi-dimensional array to another array of the same dimensions. Copying of arrays that hold primitive data types is by value. If they are reference types, they are copied by reference.

The method uses the private method recurseCopy to move through the array dimensions. The argument can be any Object, but if the argument is not an array, then the method returns null, and if the array holds reference objects at its lowest level instead of primitive data types, then an empty array of the correct size is returned.

Note that the method only looks at the length of the first row in each dimension, so it will not give sensible information unless the multi-dimensional array is "rectangular", ie unless all the rows in a given dimension have the same length.

Parameters:

o - The input (multi-dimensional) array

Returns:

A copy of the input by value

isPrimitiveArray

public static boolean isPrimitiveArray(java.lang.Object o)

Class method that returns true if the given multi-dimensional array is an array of primitive Java data types at its lowest level. It returns false if the elements of the array at its lowest level are reference types.

Parameters:

o - The array being inspected

Returns:

True if the elements at the lowest level are primitive.

isArithmeticArray

public static boolean isArithmeticArray(java.lang.Object o)

Class method that returns true if the given multi-dimensional array contains these primitive Java data types at its lowest level: byte, short, int, long, float, or double. It returns false if the elements of the array at its lowest level are boolean, char, or reference types.

Parameters:

o - The array being tested

Returns:

True if the elements at the lowest level are arithmetic primitive types

toDoubleArray

public static java.lang.Object toDoubleArray(java.lang.Object o)

Class method that converts a given input array to an array of doubles. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of doubles, then it is passed directly to output.

Parameters:

o - The input array

Returns:

The array converted to an array of doubles

toFloatArray

public static java.lang.Object toFloatArray(java.lang.Object o)

Class method that converts a given input array to an array of floats. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of floats, then it is passed directly to output.

Parameters:

o - The input array

Returns:

The array converted to an array of floats

toIntArray

public static java.lang.Object toIntArray(java.lang.Object o)

Class method that converts a given input array to an array of ints. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of ints, then it is passed directly to output. Floats and doubles are converted to ints by rounding.

Parameters:

o - The input array

Returns:

The array converted to an array of ints

toLongArray

public static java.lang.Object toLongArray(java.lang.Object o)

Class method that converts a given input array to an array of longs. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of longs, then it is passed directly to output. Floats and doubles are converted to longs by rounding.

Parameters:

o - The input array

Returns:

The array converted to an array of longs

toShortArray

public static java.lang.Object toShortArray(java.lang.Object o)

Class method that converts a given input array to an array of shorts. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of doubles, then it is passed directly to output. Floats and doubles are converted first to ints by rounding and then to shorts by casting.

Parameters:

o - The input array

Returns:

The array converted to an array of shorts

toByteArray

public static java.lang.Object toByteArray(java.lang.Object o)

Class method that converts a given input array to an array of bytes. The input array can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types then the method returns null. If the input object is not an array, the method also returns null. If the input object is an array of bytes, then it is passed directly to output. Floats and doubles are converted first to ints by rounding and then to bytes by casting.

Parameters:

o - The input array

Returns:

The array converted to an array of bytes

convertArrayElements

public static java.lang.Object convertArrayElements(java.lang.Object o,
                                    java.lang.Class outClass)

Class method that converts the given input array to an array whose elements are of the type given by the Class in the second argument. The input array (first argument) can have any dimensionality, but must contain primitive arithmetic types. If its elements are boolean, char, or reference types, then the method returns null. If the input object is not an array, the method also returns null. The second argument is a Class. If it is the Class of a primitive data type, then the elements of the first argument will be converted to that type, provided the type is arithmetic (i.e. not boolean or char); if the given class is boolean or char, the method returns null. If the given Class is that of an array, then the output type will be the type of the elements of the array; again, if these elements are of type boolean or char, the method returns null. If the given Class is not a primitive type or an array, then the method returns null. If the given object is already of the same Class as the given Class, then the object is simply passed to the output.

Note that Java provides Class constants for primitives, denoted by Integer.Type, Double.Type, etc,. These values are also returned by applying the suffix .class to a primitive variable type name, e.g. int.class has the value Integer.Type. For any Object Q, including arrays, the class is given by the method Q.getClass(). Normally, the present method would be used to to convert the elements of o to the type of the elements of object q, by invoking convertArrayType( o, q.getClass() ).

Parameters:

o - The input array

outClass - The desired type of the output elements

Returns:

The array converted to an array of the desired type

incrementArray

public static boolean incrementArray(java.lang.Object or,
                     java.lang.Object oi,
                     double sr,
                     double si)

Class method that adds the given complex number (supplied as two doubles in the last two arguments) to the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) and returns a boolean true value to indicate success. Arithmetic is done in-place, i.e. the supplied arrays are simply modified.

If the data are not arithmetic data then the method returns false. If the input data are real (second argument null) but the imaginary part of the increment variable (fourth argument) is non-zero, then the method returns false.

Parameters:

or - The real part of the array data, which must contain doubles

oi - The imaginary part of the array data, which must contain doubles; it may be null

sr - The real part of the increment number

si - The imaginary part of the increment number (must be zero if the second argument is null)

Returns:

True if the method succeeds

incrementCopyOfArray

public static java.util.ArrayList incrementCopyOfArray(java.lang.Object or,
                                       java.lang.Object oi,
                                       double sr,
                                       double si)

Class method that adds the given complex number (supplied as two doubles in the last two arguments) to the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) and returns an ArrayList holding the real and imaginary parts of the results as new arrays of doubles of the same dimensionality as the given arrays.

If the data are not arithmetic data then the method returns a null ArrayList. If the input data are real (second argument null) and the imaginary part of the increment variable (fourth argument) is zero, then the second component of the returned ArrayList will be null. If the input data are real but the imaginary part of the increment variable is non-zero, then the output data will be complex.

Parameters:

or - The real part of the array data

oi - The imaginary part of the array data (null if data are real)

sr - The real part of the increment number

si - The imaginary part of the increment number (zero if increment is real)

Returns:

containing the real and imaginary parts of the incremented array (second element null if result is real)

incrementArray

public static boolean incrementArray(java.lang.Object o,
                     double s)

Class method that adds the given real number to the given data array and returns a boolean true value to indicate success. Arithmetic is done in-place, i.e. the supplied array is simply modified.

If the data are not arithmetic data then the method returns false.

Parameters:

o - The array data, which must contain doubles

s - The increment number

Returns:

True if the method succeeds

scaleArray

public static boolean scaleArray(java.lang.Object or,
                 java.lang.Object oi,
                 double sr,
                 double si)

Class method that multiplies the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) by the given complex number (supplied as two doubles in the last two arguments) and returns a boolean true value to indicate success. Arithmetic is done in-place, i.e. the supplied arrays are simply modified.

If the data are not arithmetic data then the method returns false. If the input data are real (second argument null) but the imaginary part of the scale variable (fourth argument) is non-zero, then the method returns false.

Parameters:

or - The real part of the array data

oi - The imaginary part of the array data (null if data are real)

sr - The real part of the scaling number

si - The imaginary part of the scaling number (zero if scale is real)

Returns:

True if the method succeeds

scaleCopyOfArray

public static java.util.ArrayList scaleCopyOfArray(java.lang.Object or,
                                   java.lang.Object oi,
                                   double sr,
                                   double si)

Class method that multiplies the given complex data array (supplied in the first two arguments, containing any primitive arithmetic types) by the given complex number (supplied as two doubles in the last two arguments) and returns an ArrayList holding the real and imaginary parts of the results as new arrays of doubles of the same dimensionality as the given arrays.

If the data are not arithmetic data then the method returns a null ArrayList. If the input data are real (second argument null) and the imaginary part of the scale variable (fourth argument) is zero, then the second component of the returned ArrayList will be null. If the input data are real but the imaginary part of the scale variable is non-zero, then the output data will be complex.

Parameters:

or - The real part of the array data

oi - The imaginary part of the array data (null if data are real)

sr - The real part of the scaling number

si - The imaginary part of the scaling number (zero if scale is real)

Returns:

containing the real and imaginary parts of the rescaled array (second element null if result is real)

scaleArray

public static boolean scaleArray(java.lang.Object o,
                 double s)

Class method that multiplies the given real data array by the given real number and returns a boolean true value to indicate success. Arithmetic is done in-place, i.e. the supplied array is simply modified.

If the data are not arithmetic data then the method returns false.

Parameters:

o - The array data, which must contain doubles

s - The increment number

Returns:

True if the method succeeds

maxArray

public static double maxArray(java.lang.Object in)

Class method maxArray returns a double containing the maximum value of all the elements of the given array, if its elements are of an arithmetic data type, as determined by method isArithmeticArray. If the array contains primitive types other than doubles, the returned value is converted to a double. If the data are not arithmetic, then Double.NaN is returned.

Parameters:

in - The array to be tested

Returns:

The maximum value of the elements of the given array

minArray

public static double minArray(java.lang.Object in)

Class method that returns a double containing the minimum value of all the elements of the given array, if its elements are of an arithmetic data type, as determined by method isArithmeticArray. If the array contains primitive types other than doubles, the returned value is converted to a double. If the data are not arithmetic, then Double.NaN is returned.

Parameters:

in - The array to be tested

Returns:

double The minimum value of the elements of the given array

similarArrays

public static boolean similarArrays(java.lang.Object a1,
                    java.lang.Object a2)

Class method that tests to see if the given arrays are of a similar type: both Objects are indeed arrays, they have the same dimensionality, and their sizes in the different dimensions are the same. Finally it tests that their types are the same.

Parameters:

a1 - The first array to be compared

a2 - The second array to be compared

Returns:

True if the arrays are similar

equalArrays

public static boolean equalArrays(java.lang.Object a1,
                  java.lang.Object a2)

Class method that tests the elements of the two given arrays. If the arrays have the same dimensionality and size, if the elements are primitive Java data types, and if all the elements of one array equal those of the other array at the same position, then the method returns true. Otherwise it returns false. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns false.

Parameters:

a1 - The first array to be compared

a2 - The second array

Returns:

True if the two arrays are equal element-by-element

initializeArray

public static void initializeArray(java.lang.Object a)

Class method that sets the elements of the given array to zero. If the given object is not an array, or is an array of non-arithmetic elements, then the method returns without doing anything.

Parameters:

a - The array to be initialized

addArrays

public static java.lang.Object addArrays(java.lang.Object a1,
                         java.lang.Object a2)

Class method that adds the elements of the two given arrays. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method adds the two arrays and returns an Object of the same type. The arithmetic is done in-place in the first argument, so the returned value is simply a reference to the first argument. If a new returned array is desired, then the first argument should be a copy of the input array, using method multiArrayCopy.

If the input arrays are not the same dimensionality and size, or if at least one of them does not contain arithmetic data types, then this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1 - The first array to be added

a2 - The second array to be added

Returns:

The sum of the two arrays element-by-element

subtractArrays

public static java.lang.Object subtractArrays(java.lang.Object a1,
                              java.lang.Object a2)

Class method that subtracts the elements of the second given array from those of the first. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method subtracts the second array from the first and returns an Object of the same type. The arithmetic is done in-place in the first argument, so the returned value is simply a reference to the first argument. If a new returned array is desired, then the first argument should be a copy of the input array, using method multiArrayCopy.

If the input arrays are not the same dimensionality and size, or if at least one of them does not contain arithmetic data types, then this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1 - The array to be subtracted from

a2 - The array to be subtracted

Returns:

The result of subtracting the second array from the first element-by-element

multiplyArrays

public static java.util.ArrayList multiplyArrays(java.lang.Object a1r,
                                 java.lang.Object a1i,
                                 java.lang.Object a2r,
                                 java.lang.Object a2i)

Class method that multiplies the individual elements of two complex arrays, whose real and imaginary parts are the four given arrays. Corresponding elements are multiplied. Thus, this is not a version of matrix multiplication. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method multiplies the arrays and returns an ArrayList containing two arrays of the same type, the real and imaginary parts of the result. The arithmetic is done in-place in the first 2 arguments, so the returned values are simply references to these arguments. If new returned arrays are desired, then the first 2 arguments should be copies of the input arrays, using method multiArrayCopy.

If the input arrays are not all the same dimensionality and size, or if at least one of them does not contain arithmetic data types, the this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1r - The real part of the first array to be multiplied

a1i - The imaginary part of the first array to be multiplied

a2r - The real part of the second array to be multiplied

a2i - The imaginary part of the second array to be multiplied

Returns:

The product of the first 2 arrays by the second two, using element-by-element complex multiplication

multiplyArrays

public static java.lang.Object multiplyArrays(java.lang.Object a1,
                              java.lang.Object a2)

Class method that multiplies the individual elements of the two given arrays. Corresponding elements are multiplied. Thus, this is not a version of matrix multiplication. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method multiplies the two arrays and returns the result, an Object that is an array of the same type. The arithmetic is done in-place in the first argument, so the returned value is simply a reference to the first argument. If a new returned array is desired, then the first argument should be a copy of the input array, using method multiArrayCopy.

If the input arrays are not all the same dimensionality and size, or if at least one of them does not contain arithmetic data types, the this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1 - The first array to be multiplied

a2 - The second array to be multiplied

Returns:

The product of the two arrays element-by-element

divideArrays

public static java.util.ArrayList divideArrays(java.lang.Object a1r,
                               java.lang.Object a1i,
                               java.lang.Object a2r,
                               java.lang.Object a2i)

Class method that divides the individual elements of two complex arrays, whose real and imaginary parts are the four given arrays. Corresponding elements of the first set of arrays are divided by the elements of the second set. Integer data types use integer division. If remaindered division is required, convert all arguments to a floating type first, using for example the method toDoubleArray. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method divides the arrays and returns an ArrayList containing two arrays of the same type, the real and imaginary parts of the result. The arithmetic is done in-place in the first 2 arguments, so the returned values are simply references to these arguments. If new returned arrays are desired, then the first 2 arguments should be copies of the input arrays, using method multiArrayCopy.

If the input arrays are not all the same dimensionality and size, or if at least one of them does not contain arithmetic data types, the this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1r - The real part of the numerator array

a1i - The imaginary part of the numeratorarray

a2r - The real part of the denominator array

a2i - The imaginary part of the denominator array

Returns:

The quotient of the first 2 arrays by the second two, using element-by-element complex division

divideArrays

public static java.lang.Object divideArrays(java.lang.Object a1,
                            java.lang.Object a2)

Class method that divides the individual elements of two arrays. Corresponding elements of the first array are divided by the elements of the second. Integer data types use integer division. If remaindered division is required, convert both arguments to a floating type first, using for example the method toDoubleArray. If the arrays have the same dimensionality and size, and if the elements are arithmetic Java data types, then the method divides the arrays and returns the result as an Object that is an array of the same type. The arithmetic is done in-place in the first 2 arguments, so the returned value is simply a reference to the first argument. If a new returned array is desired, then the first argument should be a copy of the input array, using method multiArrayCopy.

If the input arrays are not the same dimensionality and size, or if at least one of them does not contain arithmetic data types, the this method returns null. If the given objects are not arrays, or are arrays of non-primitive objects, then the method also returns null.

Parameters:

a1 - The numerator array

a2 - The denominator array

Returns:

The quotient of the two arrays element-by-element

convertToNarrowBand

public static double[] convertToNarrowBand(double[] fullArray,
                           boolean oneSide,
                           int low,
                           int high)

Class method that converts a full-bandwidth spectrum to a narrow-band spectrum. It returns a double[] array containing only the elements of the original array that are required by the Triana data model for spectra. The input array can be either the real or the imaginary part of the spectrum. The bandwidth is determined by the integer indices of the edges of the band in the input array; these are the indices of the positive-frequency elements in the full-bandwidth spectrum. The method assumes that the data obeys the Triana spectral data model, but it does not check this.

Parameters:

fullArray - The input full-bandwidth spectrum

oneSide - True if the input spectrum in one-sided

low - The index of the lower edge of the returned band

high - The index of the higher edge of the returned band

Returns:

The corresponding narrow-band spectrum

See Also:

Spectrum, ComplexSpectrum

convertToOneSided

public static double[] convertToOneSided(double[] twoSide,
                         int full,
                         boolean narrowband,
                         boolean containsZeroFrequency)

Class method that takes the given array, assumed to be a two-sided spectrum (either the real or imaginary part) and returns the associated one-sided spectrum. It uses the information in the given integer full (the number of elements in the full two-sided spectrum, which is not the same as the number of elements of the given array if it is narrow-band); the given boolean narrowband (the flag that is true if the given array is a narrow-band slice of a full spectrum); and the given boolean containsZeroFrequency (true if the given array contains the zero-frequency element of the full spectrum).

The storage order is the order given by the Triana storage convention. The method extracts the one-sided spectrum essentially by copying the positive-frequency elements of the two-sided spectrum. It does not check whether the negative-frequency elements are appropriately related to the positive-frequency ones.

Parameters:

twoSide - The input array containing a two-sided spectrum

full - The number of elements in the full two-sided spectrum

narrowband - True if the input array is a narrow-band spectrum

containsZeroFrequency - True if the zero-frequency element is present in the input array

Returns:

The associated one-sided spectrum

See Also:

Spectrum, ComplexSpectrum

convertToFullSpectrum

public static double[] convertToFullSpectrum(double[] input,
                             int full,
                             boolean onesided,
                             boolean realpart,
                             boolean narrowband,
                             int low)

Class method that converts takes the given spectral data array, which can be one-sided and/or narrow-band, and which is assumed to be stored according to the Triana spectral data model, and returns the associated two-sided full-bandwidth data array. The conversion from one-sided to two-sided assumes that the data from which the spectrum was obtained are real, so that the spectrum at negative frequencies is the complex-conjugate of that at positive frequencies. In this case it reads the boolean parameter realpart to determine if it is converting the real part or the imaginary part of the spectrum. The conversion from narrow-band to full-band pads the remaining parts of the spectrum with zeros; it uses the int parameter low to determine the lowest edge of the given band.

The nature of the input array is given by the flags onesided and narrowband. The int argument full is the number of elements in the returned array.

The method does not check that the input data obeys the Triana spectral data model. The user is responsible for ensuring this.

Parameters:

input - The input array

full - The number of data points in the returned array

onesided - True if the input data are one-sided

realpart - True if the input data are the real part of a spectrum, false if imaginary part

narrowband - True if the input data are narrow-band

low - The lower bound on the frequency spectrum

Returns:

The data as a two-sided full-bandwidth spectrum

testConjugateSymmetry

public static int testConjugateSymmetry(double[] xr,
                        double[] xi)

Class method to test whether a spectral data set has the symmetry property that will result in its inverse transform being pure real or pure imaginary. If, for a full data set (not one-sided spectra, which will automatically transform to real), x[k] = ComplexConjugate(x[N-k]), then the transform will be real. If x[k] = -ComplexConjugate(x[N-k]) then the transform will be imaginary. This test should only be applied to the full data set that will be transformed.

The return value is an int. It has value +1 if the transform will be real, -1 if imaginary, 0 if there is no special symmetry.

Parameters:

xr - The real part of the input data set (can be null)

xi - The imaginary part of the input data set (can be null)

Returns:

Takes value 1, 0, or -1 for symmetry, no symmetry, antisymmetry

getFlatArray

public java.lang.Object getFlatArray()

Returns the array that holds the flattened data.

Returns:

Object The flattened array

getLengths

public int[] getLengths()

Returns the int[] that contains the lengths of the dimensions of the original array.

Returns:

int[] The original dimension lengths

getFlatLength

public int getFlatLength()

Returns the length of the flattened array, which is the total number of elements in the original array.

Returns:

int The total flattened length

getComponentName

public java.lang.String getComponentName()

Returns the name of the type of the components of the flattened array.

Returns:

String The name of the components

setFlatArray

public void setFlatArray(java.lang.Object newArray)

Sets the Array that holds the flattened data.

Parameters:

newArray - The new flattened array

setLengths

public void setLengths(int[] newLengths)

Sets the int[] that holds the lengths of the original dimensions.

Parameters:

newLengths - The new lengths array

setComponentName

public void setComponentName(java.lang.String newComponentName)

Sets the name of the type of the component of the flat array.

Parameters:

newComponentName - The new type name

restoreArray

public java.lang.Object restoreArray(boolean copy)

Returns an array of the dimensionality given by lengths and containing the data held in flatArray. It will restore to the original array that was used to create flatArray if parameter newArray is false. If the parameter is true, it will create a new array; if the elements of the old array are primitive types, they will be copied to the new array; if they are reference types the new array will contain references to them.

Parameters:

copy - True if the output should be a new object, false if the old object should be restored

Returns:

The new multidimensional array

restoreArray

public java.lang.Object restoreArray()

Creates an array of the dimensionality given by lengths and containing the data held in flatArray,/i>. It will restore to the original array that was used to create flatArray.