org.diirt.util.array

Class ListMath

java.lang.Object

org.diirt.util.array.ListMath

public class ListMath
extends Object

Math operations defined on lists of numbers.

Author:

carcassi, Mark Davis (NSCL/FRIB)

Method Summary

Modifier and Type	Method and Description
static ListDouble	add(ListNumber data, double offset) Returns a new list where all elements are added to a constant.
static ListDouble	add(ListNumber data1, ListNumber data2) Returns a list where each element is the sum of the elements of the two lists at the same index.
static List<ListNumber>	dft(ListNumber x, ListNumber y) XXX: This is just a prototype
static ListDouble	divide(ListNumber data1, ListNumber data2) Returns a list where each element is the division of the elements of the two lists at the same index.
static ListDouble	inverseRescale(ListNumber data, double numerator, double offset) Performs a linear transformation on inverse value of each number in a list.
static ListDouble	limit(ListDouble data, int start, int end) Returns a sublist of the given data.
static ListLong	limit(ListLong data, int start, int end) Returns a sublist of the given data.
static ListNumber	limit(ListNumber data, int start, int end) Returns a sublist of the given data.
static ListDouble	multiply(ListNumber data1, ListNumber data2) Returns a list where each element is the product of the elements of the two lists at the same index.
static ListDouble	pow(double base, ListNumber expons) Raises a value to the power of each value in a list.
static ListDouble	pow(ListNumber data, double expon) Raises each value in a list to the same power.
static ListDouble	rescale(ListNumber data, double factor, double offset) Performs a linear transformation on the data.
static ListDouble	subtract(ListNumber data1, ListNumber data2) Returns a list where each element is the difference of the elements of the two lists at the same index.

Methods inherited from class java.lang.Object

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

Method Detail

limit

public static ListDouble limit(ListDouble data,
                               int start,
                               int end)

Returns a sublist of the given data.

Parameters:

data - a list

start - start point for the sublist

end - end point (exclusive) for the sublist

Returns:

the sublist

limit

public static ListNumber limit(ListNumber data,
                               int start,
                               int end)

Returns a sublist of the given data.

TODO: this should go as a member method

Parameters:

data - a list

start - start point for the sublist

end - end point (exclusive) for the sublist

Returns:

the sublist

limit

public static ListLong limit(ListLong data,
                             int start,
                             int end)

Returns a sublist of the given data.

Parameters:

data - a list

start - start point for the sublist

end - end point (exclusive) for the sublist

Returns:

the sublist

rescale

public static ListDouble rescale(ListNumber data,
                                 double factor,
                                 double offset)

Performs a linear transformation on the data.

Parameters:

data - A list of numbers

factor - The multiplicative constant

offset - The additive constant

Returns:

result[x] = data[x] * factor + offset

inverseRescale

public static ListDouble inverseRescale(ListNumber data,
                                        double numerator,
                                        double offset)

Performs a linear transformation on inverse value of each number in a list.

Parameters:

data - The list of numbers to divide the numerator by

numerator - The numerator for each division

offset - The additive constant

Returns:

result[x] = numerator / data[x] + offset

pow

public static ListDouble pow(ListNumber data,
                             double expon)

Raises each value in a list to the same power.

Parameters:

data - The list of numbers to raise to a power

expon - The power to raise each number in the list to

Returns:

result[x] = data[x] ** expon

pow

public static ListDouble pow(double base,
                             ListNumber expons)

Raises a value to the power of each value in a list.

Parameters:

base - The value to raise to each power

expons - The list of exponents to raise the base value to

Returns:

result[x] = base ** expons[x]

add

public static ListDouble add(ListNumber data,
                             double offset)

Returns a new list where all elements are added to a constant.

Parameters:

data - a list of number

offset - the additive constant

Returns:

result[x] = data[x] + offset

add

public static ListDouble add(ListNumber data1,
                             ListNumber data2)

Returns a list where each element is the sum of the elements of the two lists at the same index. The lists have to match in size.

Parameters:

data1 - a list of numbers

data2 - another list of numbers

Returns:

result[x] = data1[x] + data2[x]

subtract

public static ListDouble subtract(ListNumber data1,
                                  ListNumber data2)

Returns a list where each element is the difference of the elements of the two lists at the same index. The lists have to match in size.

Parameters:

data1 - a list of numbers

data2 - another list of numbers

Returns:

result[x] = data1[x] - data2[x]

multiply

public static ListDouble multiply(ListNumber data1,
                                  ListNumber data2)

Returns a list where each element is the product of the elements of the two lists at the same index. The lists have to match in size.

Parameters:

data1 - a list of numbers

data2 - another list of numbers

Returns:

result[x] = data1[x] * data2[x]

divide

public static ListDouble divide(ListNumber data1,
                                ListNumber data2)

Returns a list where each element is the division of the elements of the two lists at the same index. The lists have to match in size.

Parameters:

data1 - a list of numbers

data2 - another list of numbers

Returns:

result[x] = data1[x] / data2[x]

dft

public static List<ListNumber> dft(ListNumber x,
                                   ListNumber y)

XXX: This is just a prototype

Parameters:

x - real part

y - imaginary part

Returns:

the real and imaginary part of the transform