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Miscellaneous Utilities (Pure Java)
/*
* Copyright (c) 2018 by Andrew Charneski.
*
* The author licenses this file to you 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 com.simiacryptus.util;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.DoubleBinaryOperator;
import java.util.function.DoubleUnaryOperator;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
/**
* The type Array util.
*/
public class ArrayUtil {
/**
* Add double [ ].
*
* @param a the a
* @param b the b
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] add(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final double[] b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x + y);
}
/**
* Add list.
*
* @param a the a
* @param b the b
* @return the list
*/
public static List add(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final List b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x + y);
}
/**
* Dot double.
*
* @param a the a
* @param b the b
* @return the double
*/
public static double dot(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final double[] b) {
return com.simiacryptus.util.ArrayUtil.sum(com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x * y));
}
/**
* Dot double.
*
* @param a the a
* @param b the b
* @return the double
*/
public static double dot(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final List b) {
return com.simiacryptus.util.ArrayUtil.sum(com.simiacryptus.util.ArrayUtil.multiply(a, b));
}
/**
* Magnitude double.
*
* @param a the a
* @return the double
*/
public static double magnitude(@javax.annotation.Nonnull final double[] a) {
return Math.sqrt(com.simiacryptus.util.ArrayUtil.dot(a, a));
}
/**
* Mean double.
*
* @param op the op
* @return the double
*/
public static double mean(@javax.annotation.Nonnull final double[] op) {
return com.simiacryptus.util.ArrayUtil.sum(op) / op.length;
}
/**
* Minus list.
*
* @param a the a
* @param b the b
* @return the list
*/
public static List minus(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final List b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x - y);
}
/**
* Multiply double [ ].
*
* @param a the a
* @param b the b
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] multiply(@javax.annotation.Nonnull final double[] a, final double b) {
return com.simiacryptus.util.ArrayUtil.op(a, (x) -> x * b);
}
/**
* Multiply double [ ].
*
* @param a the a
* @param b the b
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] multiply(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final double[] b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x * y);
}
/**
* Multiply list.
*
* @param a the a
* @param b the b
* @return the list
*/
@javax.annotation.Nonnull
public static List multiply(@javax.annotation.Nonnull final List a, final double b) {
return com.simiacryptus.util.ArrayUtil.op(a, x -> x * b);
}
/**
* Multiply list.
*
* @param a the a
* @param b the b
* @return the list
*/
public static List multiply(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final List b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x * y);
}
/**
* Op double [ ].
*
* @param a the a
* @param b the b
* @param fn the fn
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] op(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final double[] b, @javax.annotation.Nonnull final DoubleBinaryOperator fn) {
assert a.length == b.length;
@javax.annotation.Nonnull final double[] c = new double[a.length];
for (int j = 0; j < a.length; j++) {
c[j] = fn.applyAsDouble(a[j], b[j]);
}
return c;
}
/**
* Op double [ ].
*
* @param a the a
* @param fn the fn
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] op(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final DoubleUnaryOperator fn) {
@javax.annotation.Nonnull final double[] c = new double[a.length];
for (int j = 0; j < a.length; j++) {
c[j] = fn.applyAsDouble(a[j]);
}
return c;
}
/**
* Op list.
*
* @param a the a
* @param fn the fn
* @return the list
*/
@javax.annotation.Nonnull
public static List op(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final DoubleUnaryOperator fn) {
@javax.annotation.Nonnull final ArrayList list = new ArrayList<>();
for (int i = 0; i < a.size(); i++) {
@javax.annotation.Nonnull final double[] c = new double[a.get(i).length];
for (int j = 0; j < a.get(i).length; j++) {
c[j] = fn.applyAsDouble(a.get(i)[j]);
}
list.add(c);
}
return list;
}
/**
* Op list.
*
* @param a the a
* @param b the b
* @param fn the fn
* @return the list
*/
public static List op(@javax.annotation.Nonnull final List a, @javax.annotation.Nonnull final List b, @javax.annotation.Nonnull final DoubleBinaryOperator fn) {
assert a.size() == b.size();
return IntStream.range(0, a.size()).parallel().mapToObj(i -> {
assert a.get(i).length == b.get(i).length;
@javax.annotation.Nonnull final double[] c = new double[a.get(i).length];
for (int j = 0; j < a.get(i).length; j++) {
c[j] = fn.applyAsDouble(a.get(i)[j], b.get(i)[j]);
}
return c;
}).collect(Collectors.toList());
}
/**
* Subtract double [ ].
*
* @param a the a
* @param b the b
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] subtract(@javax.annotation.Nonnull final double[] a, @javax.annotation.Nonnull final double[] b) {
return com.simiacryptus.util.ArrayUtil.op(a, b, (x, y) -> x - y);
}
/**
* Sum double.
*
* @param op the op
* @return the double
*/
public static double sum(@javax.annotation.Nonnull final double[] op) {
return Arrays.stream(op).sum();
}
/**
* Sum double [ ].
*
* @param a the a
* @param b the b
* @return the double [ ]
*/
@javax.annotation.Nonnull
public static double[] sum(@javax.annotation.Nonnull final double[] a, final double b) {
return com.simiacryptus.util.ArrayUtil.op(a, (x) -> x + b);
}
/**
* Sum double.
*
* @param a the a
* @return the double
*/
public static double sum(@javax.annotation.Nonnull final List a) {
return a.stream().parallel().mapToDouble(x -> Arrays.stream(x).sum()).sum();
}
}