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/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
 * with the License. A copy of the License is located at
 *
 * http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file 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 ai.djl.ndarray;

import ai.djl.ndarray.types.Shape;
import ai.djl.util.Preconditions;

import java.util.Arrays;

/** This class contains various methods for manipulating NDArrays. */
public final class NDArrays {

    private NDArrays() {}

    private static void checkInputs(NDArray[] arrays) {
        if (arrays == null || arrays.length < 2) {
            throw new IllegalArgumentException("Passed in arrays must have at least one element");
        }
        if (arrays.length > 2
                && Arrays.stream(arrays).skip(1).anyMatch(array -> !arrays[0].shapeEquals(array))) {
            throw new IllegalArgumentException("The shape of all inputs must be the same");
        }
    }

    ////////////////////////////////////////
    // Operations: Element Comparison
    ////////////////////////////////////////

    /**
     * Returns {@code true} if all elements in {@link NDArray} a are equal to {@link NDArray} b.
     *
     * 

Examples * *

     * jshell> NDArray array = manager.ones(new Shape(3));
     * jshell> NDArrays.contentEquals(array, 1); // return true instead of boolean NDArray
     * true
     * 
* * @param a the {@link NDArray} to compare * @param n the number to compare * @return the boolean result */ public static boolean contentEquals(NDArray a, Number n) { if (a == null) { return false; } return a.contentEquals(n); } /** * Returns {@code true} if all elements in {@link NDArray} a are equal to {@link NDArray} b. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(6f).reshape(2, 3);
     * jshell> NDArray array2 = manager.create(new float[] {0f, 1f, 2f, 3f, 4f, 5f}, new Shape(2, 3));
     * jshell> NDArrays.contentEquals(array1, array2); // return true instead of boolean NDArray
     * true
     * 
* * @param a the {@link NDArray} to compare * @param b the {@link NDArray} to compare * @return the boolean result */ public static boolean contentEquals(NDArray a, NDArray b) { return a.contentEquals(b); } /** * Checks 2 {@link NDArray}s for equal shapes. * *

Shapes are considered equal if: * *

    *
  • Both {@link NDArray}s have equal rank, and *
  • size(0)...size(rank()-1) are equal for both {@link NDArray}s *
* *

Examples * *

     * jshell> NDArray array1 = manager.ones(new Shape(1, 2, 3));
     * jshell> NDArray array2 = manager.create(new Shape(1, 2, 3));
     * jshell> NDArrays.shapeEquals(array1, array2); // return true instead of boolean NDArray
     * true
     * 
* * @param a the {@link NDArray} to compare * @param b the {@link NDArray} to compare * @return {@code true} if the {@link Shape}s are the same */ public static boolean shapeEquals(NDArray a, NDArray b) { return a.shapeEquals(b); } /** * Returns {@code true} if two {@link NDArray} are element-wise equal within a tolerance. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new double[] {1e10,1e-7});
     * jshell> NDArray array2 = manager.create(new double[] {1.00001e10,1e-8});
     * jshell> NDArrays.allClose(array1, array2); // return false instead of boolean NDArray
     * false
     * jshell> NDArray array1 = manager.create(new double[] {1e10,1e-8});
     * jshell> NDArray array2 = manager.create(new double[] {1.00001e10,1e-9});
     * jshell> NDArrays.allClose(array1, array2); // return true instead of boolean NDArray
     * true
     * 
* * @param a the {@link NDArray} to compare with * @param b the {@link NDArray} to compare with * @return the boolean result */ public static boolean allClose(NDArray a, NDArray b) { return a.allClose(b); } /** * Returns {@code true} if two {@link NDArray} are element-wise equal within a tolerance. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new double[] {1e10, 1e-7});
     * jshell> NDArray array2 = manager.create(new double[] {1.00001e10, 1e-8});
     * jshell> NDArrays.allClose(array1, array2, 1e-05, 1e-08, false); // return false instead of boolean NDArray
     * false
     * jshell> NDArray array1 = manager.create(new double[] {1e10, 1e-8});
     * jshell> NDArray array2 = manager.create(new double[] {1.00001e10, 1e-9});
     * jshell> NDArrays.allClose(array1, array2, 1e-05, 1e-08, false); // return true instead of boolean NDArray
     * true
     * jshell> NDArray array1 = manager.create(new float[] {1f, Float.NaN});
     * jshell> NDArray array2 = manager.create(new float[] {1f, Float.NaN});
     * jshell> NDArrays.allClose(array1, array2, 1e-05, 1e-08, true); // return true instead of boolean NDArray
     * true
     * 
* * @param a the {@link NDArray} to compare with * @param b the {@link NDArray} to compare with * @param rtol the relative tolerance parameter * @param atol the absolute tolerance parameter * @param equalNan whether to compare NaN’s as equal. If {@code true}, NaN’s in the {@link * NDArray} will be considered equal to NaN’s in the other {@link NDArray} * @return the boolean result */ public static boolean allClose( NDArray a, NDArray b, double rtol, double atol, boolean equalNan) { return a.allClose(b, rtol, atol, equalNan); } /** * Returns the boolean {@link NDArray} for element-wise "Equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.ones(new Shape(1));
     * jshell> NDArrays.eq(array, 1);
     * ND: (1) cpu() boolean
     * [ true]
     * 
* * @param a the {@link NDArray} to compare * @param n the number to compare * @return the boolean {@link NDArray} for element-wise "Equals" comparison */ public static NDArray eq(NDArray a, Number n) { return a.eq(n); } /** * Returns the boolean {@link NDArray} for element-wise "Equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.ones(new Shape(1));
     * jshell> NDArrays.eq(1, array);
     * ND: (1) cpu() boolean
     * [ true]
     * 
* * @param n the number to compare * @param a the {@link NDArray} to compare * @return the boolean {@link NDArray} for element-wise "Equals" comparison */ public static NDArray eq(Number n, NDArray a) { return eq(a, n); } /** * Returns the boolean {@link NDArray} for element-wise "Equals" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {0f, 1f, 3f});
     * jshell> NDArray array2 = manager.arange(3f);
     * jshell> NDArrays.eq(array1, array2);
     * ND: (3) cpu() boolean
     * [ true,  true, false]
     * 
* * @param a the {@link NDArray} to compare * @param b the {@link NDArray} to compare * @return the boolean {@link NDArray} for element-wise "Equals" comparison */ public static NDArray eq(NDArray a, NDArray b) { return a.eq(b); } /** * Returns the boolean {@link NDArray} for element-wise "Not equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.arange(4f).reshape(2, 2);
     * jshell> NDArrays.neq(array, 1);
     * ND: (2, 2) cpu() boolean
     * [[ true, false],
     *  [ true,  true],
     * ]
     * 
* * @param a the {@link NDArray} to compare * @param n the number to compare * @return the boolean {@link NDArray} for element-wise "Not equals" comparison */ public static NDArray neq(NDArray a, Number n) { return a.neq(n); } /** * Returns the boolean {@link NDArray} for element-wise "Not equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.arange(f4).reshape(2, 2);
     * jshell> NDArrays.neq(1, array);
     * ND: (2, 2) cpu() boolean
     * [[ true, false],
     *  [ true,  true],
     * ]
     * 
* * @param n the number to compare * @param a the {@link NDArray} to compare * @return the boolean {@link NDArray} for element-wise "Not equals" comparison */ public static NDArray neq(Number n, NDArray a) { return neq(a, n); } /** * Returns the boolean {@link NDArray} for element-wise "Not equals" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {1f, 3f});
     * jshell> NDArrays.neq(array1, array2);
     * ND: (2) cpu() boolean
     * [false,  true]
     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {1f, 3f, 1f, 4f}, new Shape(2, 2));
     * jshell> NDArrays.neq(array1, array2); // broadcasting
     * ND: (2, 2) cpu() boolean
     * [[false,  true],
     *  [false,  true],
     * ]
     * 
* * @param a the {@link NDArray} to compare * @param b the {@link NDArray} to compare * @return the boolean {@link NDArray} for element-wise "Not equals" comparison */ public static NDArray neq(NDArray a, NDArray b) { return a.neq(b); } /** * Returns the boolean {@link NDArray} for element-wise "Greater Than" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {4f, 2f});
     * jshell> NDArrays.gt(array, 2f);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* * @param a the {@link NDArray} to compare * @param n the number to be compared against * @return the boolean {@link NDArray} for element-wise "Greater Than" comparison */ public static NDArray gt(NDArray a, Number n) { return a.gt(n); } /** * Returns the boolean {@link NDArray} for element-wise "Greater Than" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {4f, 2f});
     * jshell> NDArrays.gt(2f, array);
     * ND: (2) cpu() boolean
     * [false, false]
     * 
* * @param n the number to be compared * @param a the NDArray to be compared against * @return the boolean {@link NDArray} for element-wise "Greater Than" comparison */ public static NDArray gt(Number n, NDArray a) { return a.lt(n); } /** * Returns the boolean {@link NDArray} for element-wise "Greater Than" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {4f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 2f});
     * jshell> NDArrays.gt(array1, array2);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Greater Than" comparison */ public static NDArray gt(NDArray a, NDArray b) { return a.gt(b); } /** * Returns the boolean {@link NDArray} for element-wise "Greater or equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {4f, 2f});
     * jshell> NDArrays.gte(array, 2);
     * ND: (2) cpu() boolean
     * [ true, true]
     * 
* * @param a the {@link NDArray} to be compared * @param n the number to be compared against * @return the boolean {@link NDArray} for element-wise "Greater or equals" comparison */ public static NDArray gte(NDArray a, Number n) { return a.gte(n); } /** * Returns the boolean {@link NDArray} for element-wise "Greater or equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {4f, 2f});
     * jshell> NDArrays.gte(2, array);
     * ND: (2) cpu() boolean
     * [false,  true]
     * 
* * @param n the number to be compared * @param a the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Greater or equals" comparison */ public static NDArray gte(Number n, NDArray a) { return a.lte(n); } /** * Returns the boolean {@link NDArray} for element-wise "Greater or equals" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {4f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 2f});
     * jshell> NDArrays.gte(array1, array2);
     * ND: (2) cpu() boolean
     * [ true, true]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Greater or equals" comparison */ public static NDArray gte(NDArray a, NDArray b) { return a.gte(b); } /** * Returns the boolean {@link NDArray} for element-wise "Less" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.lt(array, 2f);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* * @param a the {@link NDArray} to be compared * @param n the number to be compared against * @return the boolean {@link NDArray} for element-wise "Less" comparison */ public static NDArray lt(NDArray a, Number n) { return a.lt(n); } /** * Returns the boolean {@link NDArray} for element-wise "Less" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.lt(2f, array);
     * ND: (2) cpu() boolean
     * [false, false]
     * 
* * @param n the number to be compared * @param a the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Less" comparison */ public static NDArray lt(Number n, NDArray a) { return a.gt(n); } /** * Returns the boolean {@link NDArray} for element-wise "Less" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 2f});
     * jshell> NDArrays.lt(array1, array2);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Less" comparison */ public static NDArray lt(NDArray a, NDArray b) { return a.lt(b); } /** * Returns the boolean {@link NDArray} for element-wise "Less or equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.lte(array, 2f);
     * ND: (2) cpu() boolean
     * [ true, true]
     * 
* * @param a the {@link NDArray} to be compared * @param n the number to be compared against * @return the boolean {@link NDArray} for element-wise "Less or equals" comparison */ public static NDArray lte(NDArray a, Number n) { return a.lte(n); } /** * Returns the boolean {@link NDArray} for element-wise "Less or equals" comparison. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.lte(2f, array);
     * ND: (2) cpu() boolean
     * [false,  true]
     * 
* * @param n the number to be compared * @param a the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Less or equals" comparison */ public static NDArray lte(Number n, NDArray a) { return a.gte(n); } /** * Returns the boolean {@link NDArray} for element-wise "Less or equals" comparison. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 2f});
     * jshell> NDArrays.lte(array1, array2)
     * ND: (2) cpu() boolean
     * [ true, true]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared against * @return the boolean {@link NDArray} for element-wise "Less or equals" comparison */ public static NDArray lte(NDArray a, NDArray b) { return a.lte(b); } /** * Returns elements chosen from the {@link NDArray} or the other {@link NDArray} depending on * condition. * *

Given three {@link NDArray}s, condition, a, and b, returns an {@link NDArray} with the * elements from a or b, depending on whether the elements from condition {@link NDArray} are * {@code true} or {@code false}. If condition has the same shape as a, each element in the * output {@link NDArray} is from this if the corresponding element in the condition is {@code * true}, and from other if {@code false}. * *

Note that all non-zero values are interpreted as {@code true} in condition {@link * NDArray}. * *

Examples * *

     * jshell> NDArray array = manager.arange(10f);
     * jshell> NDArrays.where(array.lt(5), array, array.mul(10));
     * ND: (10) cpu() float32
     * [ 0.,  1.,  2.,  3.,  4., 50., 60., 70., 80., 90.]
     * jshell> NDArray array = manager.create(new float[]{0f, 1f, 2f, 0f, 2f, 4f, 0f, 3f, 6f}, new Shape(3, 3));
     * jshell> NDArrays.where(array.lt(4), array, manager.create(-1f));
     * ND: (3, 3) cpu() float32
     * [[ 0.,  1.,  2.],
     *  [ 0.,  2., -1.],
     *  [ 0.,  3., -1.],
     * ]
     * 
* * @param condition the condition {@code NDArray} * @param a the first {@link NDArray} * @param b the other {@link NDArray} * @return the result {@link NDArray} */ public static NDArray where(NDArray condition, NDArray a, NDArray b) { return a.getNDArrayInternal().where(condition, b); } /** * Returns the maximum of a {@link NDArray} and a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArrays.maximum(array, 3f);
     * ND: (3) cpu() float32
     * [3., 3., 4.]
     * 
* * @param a the {@link NDArray} to be compared * @param n the number to be compared * @return the maximum of a {@link NDArray} and a number element-wise */ public static NDArray maximum(NDArray a, Number n) { return a.maximum(n); } /** * Returns the maximum of a number and a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArrays.maximum(3f, array);
     * ND: (3) cpu() float32
     * [3., 3., 4.]
     * 
* * @param n the number to be compared * @param a the {@link NDArray} to be compared * @return the maximum of a number and a {@link NDArray} element-wise */ public static NDArray maximum(Number n, NDArray a) { return maximum(a, n); } /** * Returns the maximum of {@link NDArray} a and {@link NDArray} b element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArray array2 = manager.create(new float[] {1f, 5f, 2f});
     * jshell> NDArrays.maximum(array1, array2);
     * ND: (3) cpu() float32
     * [2., 5., 4.]
     * jshell> NDArray array1 = manager.eye(2);
     * jshell> NDArray array2 = manager.create(new float[] {0.5f, 2f});
     * jshell> NDArrays.maximum(array1, array2); // broadcasting
     * ND: (2, 2) cpu() float32
     * [[1. , 2. ],
     *  [0.5, 2. ],
     * ]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared * @return the maximum of {@link NDArray} a and {@link NDArray} b element-wise */ public static NDArray maximum(NDArray a, NDArray b) { return a.maximum(b); } /** * Returns the minimum of a {@link NDArray} and a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArrays.minimum(array, 3f);
     * ND: (3) cpu() float32
     * [2., 3., 3.]
     * 
* * @param a the {@link NDArray} to be compared * @param n the number to be compared * @return the minimum of a {@link NDArray} and a number element-wise */ public static NDArray minimum(NDArray a, Number n) { return a.minimum(n); } /** * Returns the minimum of a number and a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArrays.minimum(3f, array);
     * ND: (3) cpu() float32
     * [2., 3., 3.]
     * 
* * @param n the number to be compared * @param a the {@link NDArray} to be compared * @return the minimum of a number and a {@link NDArray} element-wise */ public static NDArray minimum(Number n, NDArray a) { return minimum(a, n); } /** * Returns the minimum of {@link NDArray} a and {@link NDArray} b element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {2f, 3f, 4f});
     * jshell> NDArray array2 = manager.create(new float[] {1f, 5f, 2f});
     * jshell> NDArrays.minimum(array1, array2);
     * ND: (3) cpu() float32
     * [1., 3., 2.]
     * jshell> NDArray array1 = manager.eye(2);
     * jshell> NDArray array2 = manager.create(new float[] {0.5f, 2f});
     * jshell> NDArrays.minimum(array1, array2); // broadcasting
     * ND: (2, 2) cpu() float32
     * [[0.5, 0. ],
     *  [0. , 1. ],
     * ]
     * 
* * @param a the {@link NDArray} to be compared * @param b the {@link NDArray} to be compared * @return the minimum of {@link NDArray} a and {@link NDArray} b element-wise */ public static NDArray minimum(NDArray a, NDArray b) { return a.minimum(b); } /** * Returns portion of the {@link NDArray} given the index boolean {@link NDArray} along first * axis. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f, 3f, 4f, 5f, 6f}, new Shape(3, 2));
     * jshell> NDArray mask = manager.create(new boolean[] {true, false, true});
     * jshell> NDArrays.booleanMask(array, mask);
     * ND: (2, 2) cpu() float32
     * [[1., 2.],
     *  [5., 6.],
     * ]
     * 
* * @param data the {@link NDArray} to operate on * @param index the boolean {@link NDArray} mask * @return the result {@link NDArray} */ public static NDArray booleanMask(NDArray data, NDArray index) { return booleanMask(data, index, 0); } /** * Returns portion of the {@link NDArray} given the index boolean {@link NDArray} along given * axis. * * @param data the {@link NDArray} to operate on * @param index the boolean {@link NDArray} mask * @param axis an integer that represents the axis of {@link NDArray} to mask from * @return the result {@link NDArray} */ public static NDArray booleanMask(NDArray data, NDArray index, int axis) { return data.booleanMask(index, axis); } /** * Sets all elements of the given {@link NDArray} outside the sequence {@link NDArray} to a * constant value. * *

This function takes an n-dimensional input array of the form [batch_size, * max_sequence_length, ....] and returns an array of the same shape. Parameter {@code * sequenceLength} is used to handle variable-length sequences. {@code sequenceLength} should be * an input array of positive ints of dimension [batch_size]. * * @param data the {@link NDArray} to operate on * @param sequenceLength used to handle variable-length sequences * @param value the constant value to be set * @return the result {@link NDArray} */ public static NDArray sequenceMask(NDArray data, NDArray sequenceLength, float value) { return data.sequenceMask(sequenceLength, value); } /** * Sets all elements of the given {@link NDArray} outside the sequence {@link NDArray} to 0. * *

This function takes an n-dimensional input array of the form [batch_size, * max_sequence_length, ....] and returns an array of the same shape. Parameter {@code * sequenceLength} is used to handle variable-length sequences. {@code sequenceLength} should be * an input array of positive ints of dimension [batch_size]. * * @param data the {@link NDArray} to operate on * @param sequenceLength used to handle variable-length sequences * @return the result {@link NDArray} */ public static NDArray sequenceMask(NDArray data, NDArray sequenceLength) { return data.sequenceMask(sequenceLength); } //////////////////////////////////////// // Operations: Element Arithmetic //////////////////////////////////////// /** * Adds a number to the {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.add(array, 2f);
     * ND: (2) cpu() float32
     * [3., 4.]
     * 
* * @param a the {@link NDArray} to be added to * @param n the number to add * @return the result {@link NDArray} */ public static NDArray add(NDArray a, Number n) { return a.add(n); } /** * Adds a {@link NDArray} to a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.add(2f, array);
     * ND: (2) cpu() float32
     * [3., 4.]
     * 
* * @param n the number to be added to * @param a the {@link NDArray} to add * @return the result {@link NDArray} */ public static NDArray add(Number n, NDArray a) { return a.add(n); } /** * Adds a {@link NDArray} to a {@link NDArray} element-wise. * *

The shapes of all of the {@link NDArray}s must be the same. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.add(array, array, array);
     * ND: (2) cpu() float32
     * [3., 6.]
     * 
* * @param arrays the {@link NDArray}s to add together * @return the result {@link NDArray} * @throws IllegalArgumentException arrays must have at least two elements * @throws IllegalArgumentException the shape of all inputs must be the same */ public static NDArray add(NDArray... arrays) { checkInputs(arrays); if (arrays.length == 2) { return arrays[0].add(arrays[1]); } try (NDArray array = NDArrays.stack(new NDList(arrays))) { return array.sum(new int[] {0}); } } /** * Subtracts a number from the {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> array.sub(2f);
     * ND: (2) cpu() float32
     * [-1.,  0.]
     * 
* * @param a the {@link NDArray} to be subtracted * @param n the number to subtract from * @return the result {@link NDArray} */ public static NDArray sub(NDArray a, Number n) { return a.sub(n); } /** * Subtracts a {@link NDArray} from a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.sub(3f, array);
     * ND: (2) cpu() float32
     * [2., 1.]
     * 
* * @param n the number to be subtracted * @param a the {@link NDArray} to subtract from * @return the result {@link NDArray} */ public static NDArray sub(Number n, NDArray a) { return a.getNDArrayInternal().rsub(n); } /** * Subtracts a {@link NDArray} from a {@link NDArray} element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(9f).reshape(3, 3);
     * jshell> NDArray array2 = manager.arange(3f);
     * jshell> NDArrays.sub(array1, array2); // broadcasting
     * ND: (3, 3) cpu() float32
     * [[0., 0., 0.],
     *  [3., 3., 3.],
     *  [6., 6., 6.],
     * ]
     * 
* * @param a the {@link NDArray} to be subtracted * @param b the {@link NDArray} to subtract from * @return the result {@link NDArray} */ public static NDArray sub(NDArray a, NDArray b) { return a.sub(b); } /** * Multiplies the {@link NDArray} by a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.mul(array, 3f);
     * ND: (2) cpu() float32
     * [3., 6.]
     * 
* * @param a the NDArray to be multiplied * @param n the number to multiply by * @return the result {@link NDArray} */ public static NDArray mul(NDArray a, Number n) { return a.mul(n); } /** * Multiplies a number by a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.mul(3f, array);
     * ND: (2) cpu() float32
     * [3., 6.]
     * 
* * @param n the number to be multiplied * @param a the {@link NDArray} to multiply by * @return the result {@link NDArray} */ public static NDArray mul(Number n, NDArray a) { return a.mul(n); } /** * Multiplies all of the {@link NDArray}s together element-wise. * *

The shapes of all of the {@link NDArray}s must be the same. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.mul(array, array, array);
     * ND: (2) cpu() float32
     * [1., 8.]
     * 
* * @param arrays the {@link NDArray}s to multiply together * @return the result {@link NDArray} * @throws IllegalArgumentException arrays must have at least two elements * @throws IllegalArgumentException the shape of all inputs must be the same */ public static NDArray mul(NDArray... arrays) { checkInputs(arrays); if (arrays.length == 2) { return arrays[0].mul(arrays[1]); } try (NDArray array = NDArrays.stack(new NDList(arrays))) { return array.prod(new int[] {0}); } } /** * Divides the {@link NDArray} by a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.div(array, 4f);
     * ND: (5) cpu() float32
     * [0.  , 0.25, 0.5 , 0.75, 1.  ]
     * 
* * @param a the {@link NDArray} to be be divided * @param n the number to divide by * @return the result {@link NDArray} */ public static NDArray div(NDArray a, Number n) { return a.div(n); } /** * Divides a number by a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f).add(1);
     * jshell> NDArrays.div(4f, array);
     * ND: (5) cpu() float32
     * [4.    , 2.    , 1.3333, 1.    , 0.8   ]
     * 
* * @param n the number to be be divided * @param a the {@link NDArray} to divide by * @return the result {@link NDArray} */ public static NDArray div(Number n, NDArray a) { return a.getNDArrayInternal().rdiv(n); } /** * Divides a {@link NDArray} by a {@link NDArray} element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(9f).reshape(3, 3);
     * jshell> NDArray array2 = manager.ones(new Shape(3)).mul(10);
     * jshell> NDArrays.div(array1, array2); // broadcasting
     * ND: (3, 3) cpu() float32
     * [[0. , 0.1, 0.2],
     *  [0.3, 0.4, 0.5],
     *  [0.6, 0.7, 0.8],
     * ]
     * 
* * @param a the {@link NDArray} to be be divided * @param b the {@link NDArray} to divide by * @return the result {@link NDArray} */ public static NDArray div(NDArray a, NDArray b) { return a.div(b); } /** * Returns element-wise remainder of division. * *

Examples * *

     * jshell> NDArray array = manager.arange(7f);
     * jshell> NDArrays.mod(array, 5f);
     * ND: (7) cpu() float32
     * [0., 1., 2., 3., 4., 0., 1.]
     * 
* * @param a the dividend {@link NDArray} * @param n the divisor number * @return the result {@link NDArray} */ public static NDArray mod(NDArray a, Number n) { return a.mod(n); } /** * Returns element-wise remainder of division. * *

Examples * *

     * jshell> NDArray array = manager.arange(7f).add(1);
     * jshell> NDArrays.mod(5f, array);
     * ND: (7) cpu() float32
     * [0., 1., 2., 1., 0., 5., 5.]
     * 
* * @param n the dividend number * @param a the divisor {@link NDArray} * @return the result {@link NDArray} */ public static NDArray mod(Number n, NDArray a) { return a.getNDArrayInternal().rmod(n); } /** * Returns element-wise remainder of division. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {4f, 7f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 3f});
     * jshell> NDArrays.mod(array1, array2);
     * ND: (2) cpu() float32
     * [0., 1.]
     * 
* * @param a the dividend NDArray * @param b the dividend NDArray * @return the result {@link NDArray} */ public static NDArray mod(NDArray a, NDArray b) { return a.mod(b); } /** * Takes the power of the {@link NDArray} with a number element-wise. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.pow(array, 4f);
     * ND: (6) cpu() float32
     * [  0.,   1.,   8.,  27.,  64., 125.]
     * 
* * @param a the {@link NDArray} to be taken the power with * @param n the number to take the power with * @return the result {@link NDArray} */ public static NDArray pow(NDArray a, Number n) { return a.pow(n); } /** * Takes the power of a number with a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.pow(4f, array);
     * ND: (5) cpu() float32
     * [  1.,   4.,  16.,  64., 256.]
     * 
* * @param n the number to be taken the power with * @param a the {@link NDArray} to take the power with * @return the result {@link NDArray} */ public static NDArray pow(Number n, NDArray a) { return a.getNDArrayInternal().rpow(n); } /** * Takes the power of a {@link NDArray} with a {@link NDArray} element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(6f).reshape(3, 2);
     * jshell> NDArray array2 = manager.create(new float[] {2f, 3f});
     * jshell> NDArrays.pow(array1, array2); // broadcasting
     * ND: (3, 2) cpu() float32
     * [[  0.,   1.],
     *  [  4.,  27.],
     *  [ 16., 125.],
     * ]
     * 
* * @param a the {@link NDArray} to be taken the power with * @param b the {@link NDArray} to take the power with * @return the result {@link NDArray} */ public static NDArray pow(NDArray a, NDArray b) { return a.pow(b); } /** * Adds a number to the {@link NDArray} element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.addi(array, 2f);
     * ND: (2) cpu() float32
     * [3., 4.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [3., 4.]
     * 
* * @param a the {@link NDArray} to be added to * @param n the number to add * @return the result {@link NDArray} */ public static NDArray addi(NDArray a, Number n) { return a.addi(n); } /** * Adds a {@link NDArray} to a number element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.addi(2f, array);
     * ND: (2) cpu() float32
     * [3., 4.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [3., 4.]
     * 
* * @param a the number to be added to * @param n the {@link NDArray} to add * @return the result {@link NDArray} */ public static NDArray addi(Number n, NDArray a) { return a.addi(n); } /** * Adds all of the {@link NDArray}s together element-wise in place. * *

The shapes of all of the {@link NDArray}s must be the same. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f});
     * jshell> NDArray array3 = manager.create(new float[] {5f, 6f});
     * jshell> NDArrays.addi(array1, array2, array3);
     * ND: (2) cpu() float32
     * [9., 12.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [9., 12.]
     * 
* * @param arrays the {@link NDArray}s to add together * @return the result {@link NDArray} * @throws IllegalArgumentException arrays must have at least two elements */ public static NDArray addi(NDArray... arrays) { checkInputs(arrays); Arrays.stream(arrays).skip(1).forEachOrdered(array -> arrays[0].addi(array)); return arrays[0]; } /** * Subtracts a number from the {@link NDArray} element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.subi(array, 2f);
     * ND: (2) cpu() float32
     * [-1.,  0.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [-1.,  0.]
     * 
* * @param a the {@link NDArray} to be subtracted * @param n the number to subtract from * @return the result {@link NDArray} */ public static NDArray subi(NDArray a, Number n) { return a.subi(n); } /** * Subtracts a {@link NDArray} from a number element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.subi(3f, array);
     * ND: (2) cpu() float32
     * [2., 1.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [2., 1.]
     * 
* * @param n the number to be subtracted * @param a the {@link NDArray} to subtract from * @return the result {@link NDArray} */ public static NDArray subi(Number n, NDArray a) { return a.getNDArrayInternal().rsubi(n); } /** * Subtracts a {@link NDArray} from a {@link NDArray} element-wise in place. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(9f).reshape(3, 3);
     * jshell> NDArray array2 = manager.arange(3f);
     * jshell> NDArrays.subi(array1, array2); // broadcasting
     * ND: (3, 3) cpu() float32
     * [[0., 0., 0.],
     *  [3., 3., 3.],
     *  [6., 6., 6.],
     * ]
     * jshell> array1;
     * [[0., 0., 0.],
     *  [3., 3., 3.],
     *  [6., 6., 6.],
     * ]
     * 
* * @param a the {@link NDArray} to be subtracted * @param b the {@link NDArray} to subtract from * @return the result {@link NDArray} */ public static NDArray subi(NDArray a, NDArray b) { return a.subi(b); } /** * Multiplies the {@link NDArray} by a number element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.muli(array, 3f);
     * ND: (2) cpu() float32
     * [3., 6.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [3., 6.]
     * 
* * @param a the NDArray to be multiplied * @param n the number to multiply by * @return the result {@link NDArray} */ public static NDArray muli(NDArray a, Number n) { return a.muli(n); } /** * Multiplies a number by a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.muli(3f, array);
     * ND: (2) cpu() float32
     * [3., 6.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [3., 6.]
     * 
* * @param n the number to multiply by * @param a the {@link NDArray} to multiply by * @return the result {@link NDArray} */ public static NDArray muli(Number n, NDArray a) { return a.muli(n); } /** * Multiplies all of the {@link NDArray}s together element-wise in place. * *

The shapes of all of the {@link NDArray}s must be the same. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f});
     * jshell> NDArray array3 = manager.create(new float[] {5f, 6f});
     * jshell> NDArrays.muli(array1, array2, array3);
     * ND: (2) cpu() float32
     * [15., 48.]
     * jshell> array;
     * ND: (2) cpu() float32
     * [15., 48.]
     * 
* * @param arrays the {@link NDArray}s to multiply together * @return the result {@link NDArray} * @throws IllegalArgumentException arrays must have at least two elements */ public static NDArray muli(NDArray... arrays) { checkInputs(arrays); Arrays.stream(arrays).skip(1).forEachOrdered(array -> arrays[0].muli(array)); return arrays[0]; } /** * Divides a number by a {@link NDArray} element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.divi(array, 4f);
     * ND: (5) cpu() float32
     * [0.  , 0.25, 0.5 , 0.75, 1.  ]
     * jshell> array;
     * ND: (5) cpu() float32
     * [0.  , 0.25, 0.5 , 0.75, 1.  ]
     * 
* * @param a the {@link NDArray} to be be divided * @param n the number to divide by * @return the result {@link NDArray} */ public static NDArray divi(NDArray a, Number n) { return a.divi(n); } /** * Divides a number by a {@link NDArray} element-wise. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f).add(1);
     * jshell> NDArrays.divi(4f, array);
     * ND: (5) cpu() float32
     * [4.    , 2.    , 1.3333, 1.    , 0.8   ]
     * jshell> array;
     * ND: (5) cpu() float32
     * [4.    , 2.    , 1.3333, 1.    , 0.8   ]
     * 
* * @param n the number to be be divided * @param a the {@link NDArray} to divide by * @return the result {@link NDArray} */ public static NDArray divi(Number n, NDArray a) { return a.getNDArrayInternal().rdivi(n); } /** * Divides a {@link NDArray} by a {@link NDArray} element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(9f).reshape(3, 3);
     * jshell> NDArray array2 = manager.ones(new Shape(3)).mul(10);
     * jshell> NDArrays.divi(array1, array2); // broadcasting
     * ND: (3, 3) cpu() float32
     * [[0. , 0.1, 0.2],
     *  [0.3, 0.4, 0.5],
     *  [0.6, 0.7, 0.8],
     * ]
     * jshell> array1;
     * [[0. , 0.1, 0.2],
     *  [0.3, 0.4, 0.5],
     *  [0.6, 0.7, 0.8],
     * ]
     * 
* * @param a the {@link NDArray} to be be divided * @param b the {@link NDArray} to divide by * @return the result {@link NDArray} */ public static NDArray divi(NDArray a, NDArray b) { return a.divi(b); } /** * Returns element-wise remainder of division in place. * *

Examples * *

     * jshell> NDArray array = manager.arange(7f);
     * jshell> NDArrays.modi(array, 5f);
     * ND: (7) cpu() float32
     * [0., 1., 2., 3., 4., 0., 1.]
     * jshell> array;
     * ND: (7) cpu() float32
     * [0., 1., 2., 3., 4., 0., 1.]
     * 
* * @param a the dividend {@link NDArray} * @param n the divisor number * @return the result {@link NDArray} */ public static NDArray modi(NDArray a, Number n) { return a.modi(n); } /** * Returns element-wise remainder of division in place. * *

Examples * *

     * jshell> NDArray array = manager.arange(7f);
     * jshell> NDArrays.modi(5f, array);
     * ND: (7) cpu() float32
     * [0., 0., 1., 2., 1., 0., 5.]
     * jshell> array;
     * ND: (7) cpu() float32
     * [0., 0., 1., 2., 1., 0., 5.]
     * 
* * @param n the dividend number * @param a the divisor {@link NDArray} * @return the result {@link NDArray} */ public static NDArray modi(Number n, NDArray a) { return a.getNDArrayInternal().rmodi(n); } /** * Returns element-wise remainder of division. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {4f, 7f});
     * jshell> NDArray array2 = manager.create(new float[] {2f, 3f});
     * jshell> NDArrays.modi(array1, array2);
     * ND: (2) cpu() float32
     * [0., 1.]
     * jshell> array1;
     * ND: (2) cpu() float32
     * [0., 1.]
     * 
* * @param a the dividend NDArray * @param b the dividend NDArray * @return the result {@link NDArray} */ public static NDArray modi(NDArray a, NDArray b) { return a.modi(b); } /** * Takes the power of the {@link NDArray} with a number element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.powi(array, 4f);
     * ND: (6) cpu() float32
     * [  0.,   1.,   8.,  27.,  64., 125.]
     * jshell> array;
     * ND: (6) cpu() float32
     * [  0.,   1.,   8.,  27.,  64., 125.]
     * 
* * @param a the {@link NDArray} to be taken the power with * @param n the number to take the power with * @return the result {@link NDArray} */ public static NDArray powi(NDArray a, Number n) { return a.powi(n); } /** * Takes the power of a number with a {@link NDArray} element-wise in place. * *

Examples * *

     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.powi(4f, array);
     * ND: (5) cpu() float32
     * [  1.,   4.,  16.,  64., 256.]
     * jshell> array;
     * ND: (5) cpu() float32
     * [  1.,   4.,  16.,  64., 256.]
     * 
* * @param n the number to be taken the power with * @param a the {@link NDArray} to take the power with * @return the result {@link NDArray} */ public static NDArray powi(Number n, NDArray a) { return a.getNDArrayInternal().rpowi(n); } /** * Takes the power of a {@link NDArray} with a {@link NDArray} element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.arange(6f).reshape(3, 2);
     * jshell> NDArray array2 = manager.create(new float[] {2f, 3f});
     * jshell> NDArrays.powi(array1, array2); // broadcasting
     * ND: (3, 2) cpu() float32
     * [[  0.,   1.],
     *  [  4.,  27.],
     *  [ 16., 125.],
     * ]
     * jshell> array1;
     * ND: (3, 2) cpu() float32
     * [[  0.,   1.],
     *  [  4.,  27.],
     *  [ 16., 125.],
     * ]
     * 
* * @param a the {@link NDArray} to be taken the power with * @param b the {@link NDArray} to take the power with * @return the result {@link NDArray} */ public static NDArray powi(NDArray a, NDArray b) { return a.powi(b); } /** * Dot product of {@link NDArray} a and {@link NDArray} b. * *
    *
  • If both the {@link NDArray} and the other {@link NDArray} are 1-D {@link NDArray}s, it * is inner product of vectors (without complex conjugation). *
  • If both the {@link NDArray} and the other {@link NDArray} are 2-D {@link NDArray}s, it * is matrix multiplication. *
  • If either the {@link NDArray} or the other {@link NDArray} is 0-D {@link NDArray} * (scalar), it is equivalent to mul. *
  • If the {@link NDArray} is N-D {@link NDArray} and the other {@link NDArray} is 1-D * {@link NDArray}, it is a sum product over the last axis of those. *
  • If the {@link NDArray} is N-D {@link NDArray} and the other {@link NDArray} is M-D * {@link NDArray}(where M>=2), it is a sum product over the last axis of this * {@link NDArray} and the second-to-last axis of the other {@link NDArray} *
* *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f, 3f});
     * jshell> NDArray array2 = manager.create(new float[] {4f, 5f, 6f});
     * jshell> NDArrays.dot(array1, array2); // inner product
     * ND: () cpu() float32
     * 32.
     * jshell> array1 = manager.create(new float[] {1f, 2f, 3f, 4f}, new Shape(2, 2));
     * jshell> array2 = manager.create(new float[] {5f, 6f, 7f, 8f}, new Shape(2, 2));
     * jshell> NDArrays.dot(array1, array2); // matrix multiplication
     * ND: (2, 2) cpu() float32
     * [[19., 22.],
     *  [43., 50.],
     * ]
     * jshell> array1 = manager.create(new float[] {1f, 2f, 3f, 4f}, new Shape(2, 2));
     * jshell> array2 = manager.create(5f);
     * jshell> NDArrays.dot(array1, array2);
     * ND: (2, 2) cpu() float32
     * [[ 5., 10.],
     *  [15., 20.],
     * ]
     * jshell> array1 = manager.create(new float[] {1f, 2f, 3f, 4f}, new Shape(2, 2));
     * jshell> array2 = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.dot(array1, array2);
     * ND: (2) cpu() float32
     * [ 5., 11.]
     * jshell> array1 = manager.create(new float[] {1f, 2f, 3f, 4f, 5f, 6f, 7f, 8f}, new Shape(2, 2, 2));
     * jshell> array2 = manager.create(new float[] {1f, 2f, 3f ,4f}, new Shape(2, 2));
     * jshell> NDArrays.dot(array1, array2);
     * ND: (2, 2, 2) cpu() float32
     * [[[ 7., 10.],
     *   [15., 22.],
     *  ],
     *  [[23., 34.],
     *   [31., 46.],
     *  ],
     * ]
     * 
* * @param a the {@link NDArray} to perform dot product with * @param b the {@link NDArray} to perform dot product with * @return the result {@link NDArray} */ public static NDArray dot(NDArray a, NDArray b) { return a.dot(b); } /** * Product matrix of this {@code NDArray} and the other {@code NDArray}. * *

The behavior depends on the arguments in the following way. * *

    *
  • If both this {@code NDArray} and the other {@code NDArray} are 2-D {@code NDArray}s, * they are multiplied like conventional matrices *
  • If either this {@code NDArray} or the other {@code NDArray} is N-D {@code NDArray}, N * > 2 , it is treated as a stack of matrices residing in the last two indexes and * broadcast accordingly. *
  • If this {@code NDArray} is 1-D {@code NDArray}, it is promoted to a matrix by * prepending a 1 to its dimensions. After matrix multiplication the prepended 1 is * removed. *
  • If other {@code NDArray} is 1-D {@code NDArray}, it is promoted to a matrix by * appending a 1 to its dimensions. After matrix multiplication the appended 1 is removed. *
* *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 0f, 0f, 1f}, new Shape(2, 2));
     * jshell> NDArray array2 = manager.create(new float[] {4f, 1f, 2f, 2f}, new Shape(2, 2));
     * jshell> NDArrays.matMul(array1, array2); // for 2-D arrays, it is the matrix product
     * ND: (2, 2) cpu() float32
     * [[4., 1.],
     *  [2., 2.],
     * ]
     * jshell> array1 = manager.create(new float[] {1f, 0f, 0f, 1f}, new Shape(2, 2));
     * jshell> array2 = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.matMul(array1, array2);
     * ND: (2) cpu() float32
     * [1., 2.]
     * jshell> array1 = manager.create(new float[] {1f, 0f, 0f, 1f}, new Shape(2, 2));
     * jshell> array2 = manager.create(new float[] {1f, 2f});
     * jshell> NDArrays.matMul(array1, array2);
     * ND: (2) cpu() float32
     * [1., 2.]
     * jshell> array1 = manager.arange(2f * 2f * 4f).reshape(2, 2, 4);
     * jshell> array2 = manager.arange(2f * 2f * 4f).reshape(2, 4, 2);
     * jshell> NDArrays.matMul(array1, array2);
     * ND: () cpu() float32
     * 98.
     * 
* * @param a the {@link NDArray} to perform matrix product with * @param b the {@link NDArray} to perform matrix product with * @return the result {@code NDArray} */ public static NDArray matMul(NDArray a, NDArray b) { return a.matMul(b); } /** * Joins a sequence of {@link NDArray}s in {@link NDList} along the first axis. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {0f, 1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f, 5f});
     * jshell> NDArray array3 = manager.create(new float[] {6f, 7f, 8f});
     * jshell> NDArrays.stack(new NDList(array1, array2, array3));
     * ND: (3, 3) cpu() float32
     * [[0., 1., 2.],
     *  [3., 4., 5.],
     *  [6., 7., 8.],
     * ]
     * 
* * @param arrays the input {@link NDList}. Each {@link NDArray} in the {@link NDList} must have * the same shape as the {@link NDArray} * @return the result {@link NDArray}. The stacked {@link NDArray} has one more dimension than * the {@link NDArray}s in {@link NDList} */ public static NDArray stack(NDList arrays) { return stack(arrays, 0); } /** * Joins a sequence of {@link NDArray}s in {@link NDList} along a new axis. * *

The axis parameter specifies the index of the new axis in the dimensions of the result. * For example, if axis=0 it will be the first dimension and if axis=-1 it will be the last * dimension. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {0f, 1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f, 5f});
     * jshell> NDArrays.stack(new NDList(array1, array2), 0);
     * ND: (2, 3) cpu() float32
     * [[0., 1., 2.],
     *  [3., 4., 5.],
     * ]
     * jshell> NDArray array1 = manager.create(new float[] {0f, 1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f, 5f});
     * jshell> NDArrays.stack(new NDList(array1, array2), 1);
     * ND: (3, 2) cpu() float32
     * [[0., 3.],
     *  [1., 4.],
     *  [2., 5.],
     * ]
     * 
* * @param arrays the input {@link NDList}. Each {@link NDArray} in the {@link NDList} must have * the same shape as the {@link NDArray} * @param axis the axis in the result {@link NDArray} along which the input {@link NDList} are * stacked * @return the result {@link NDArray}. The stacked {@link NDArray} has one more dimension than * the the {@link NDArray} */ public static NDArray stack(NDList arrays, int axis) { Preconditions.checkArgument(arrays.size() > 0, "need at least one array to stack"); NDArray array = arrays.head(); return array.getNDArrayInternal().stack(arrays.subNDList(1), axis); } /** * Joins a {@link NDList} along the first axis. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {0f, 1f, 2f});
     * jshell> NDArray array2 = manager.create(new float[] {3f, 4f, 5f});
     * jshell> NDArray array3 = manager.create(new float[] {6f, 7f, 8f});
     * jshell> NDArrays.concat(new NDList(array1, array2, array3));
     * ND: (9) cpu() float32
     * [0., 1., 2., 3., 4., 5., 6., 7., 8.]
     * 
* * @param arrays a {@link NDList} which have the same shape as the {@link NDArray}, except in * the dimension corresponding to axis * @return the concatenated {@link NDArray} */ public static NDArray concat(NDList arrays) { return concat(arrays, 0); } /** * Joins a {@link NDList} along an existing axis. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new float[] {1f, 2f, 3f, 4f}, new Shape(2, 2));
     * jshell> NDArray array2 = manager.create(new float[] {5f, 6f}, new Shape(1, 2));
     * jshell> NDArrays.concat(new NDList(array1, array2), 0);
     * ND: (3, 2) cpu() float32
     * [[1., 2.],
     *  [3., 4.],
     *  [5., 6.],
     * ]
     * jshell> NDArrays.concat(new NDList(array1, array2.transpose()), 1);
     * ND: (2, 3) cpu() float32
     * [[1., 2., 5.],
     *  [3., 4., 6.],
     * ]
     * 
* * @param arrays a {@link NDList} which have the same shape as the {@link NDArray}, except in * the dimension corresponding to axis * @param axis the axis along which the {@link NDList} will be joined * @return the concatenated {@link NDArray} */ public static NDArray concat(NDList arrays, int axis) { Preconditions.checkArgument(arrays.size() > 0, "need at least one array to concatenate"); if (arrays.size() == 1) { return arrays.singletonOrThrow().duplicate(); } NDArray array = arrays.head(); return array.getNDArrayInternal().concat(arrays.subNDList(1), axis); } /** * Returns the truth value of {@link NDArray} a AND {@link NDArray} b element-wise. * *

The shapes of {@link NDArray} a and {@link NDArray} b must be broadcastable. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new boolean[] {true});
     * jshell> NDArray array2 = manager.create(new boolean[] {false});
     * jshell> NDArrays.logicalAnd(array1, array2);
     * ND: (1) cpu() boolean
     * [false]
     * jshell> array1 = manager.create(new boolean[] {true, false});
     * jshell> array2 = manager.create(new boolean[] {false, false});
     * jshell> NDArrays.logicalAnd(array.gt(1), array.lt(4));
     * ND: (2) cpu() boolean
     * [false, false]
     * 
* * @param a the {@link NDArray} to operate on * @param b the {@link NDArray} to operate on * @return the boolean {@link NDArray} of the logical AND operation applied to the elements of * the {@link NDArray} a and {@link NDArray} b */ public static NDArray logicalAnd(NDArray a, NDArray b) { return a.logicalAnd(b); } /** * Computes the truth value of {@link NDArray} a AND {@link NDArray} b element-wise. * *

Examples * *

     * jshell> NDArray array1 = manager.create(new boolean[] {true});
     * jshell> NDArray array2 = manager.create(new boolean[] {false});
     * jshell> NDArrays.logicalOr(array1, array2);
     * ND: (1) cpu() boolean
     * [ true]
     * jshell> array1 = manager.create(new boolean[] {true, false});
     * jshell> array2 = manager.create(new boolean[] {false, false});
     * jshell> NDArrays.logicalOr(array1, array2);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* *
     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.logicalOr(array.lt(1), array.gt(3));
     * ND: (5) cpu() boolean
     * [ true, false, false, false,  true]
     * 
* * @param a the {@link NDArray} to operate on * @param b the {@link NDArray} to operate on * @return the boolean {@link NDArray} of the logical AND operation applied to the elements of * the {@link NDArray} a and {@link NDArray} b */ public static NDArray logicalOr(NDArray a, NDArray b) { return a.logicalOr(b); } /** * Computes the truth value of {@link NDArray} a AND {@link NDArray} b element-wise. * *

Examples * *

     * jshell> NDArray array = manager.create(new boolean[] {true});
     * jshell> NDArrays.logicalXor(array1, array2);
     * ND: (1) cpu() boolean
     * [ true]
     * jshell> array1 = manager.create(new boolean[] {true, false});
     * jshell> array2 = manager.create(new boolean[] {false, false});
     * jshell> NDArrays.logicalXor(array1, array2);
     * ND: (2) cpu() boolean
     * [ true, false]
     * 
* *
     * jshell> NDArray array = manager.arange(5f);
     * jshell> NDArrays.logicalXor(array.lt(1), array.gt(3));
     * ND: (5) cpu() boolean
     * [ true, false, false, false,  true]
     * 
* * @param a the {@link NDArray} to operate on * @param b the {@link NDArray} to operate on * @return the boolean {@link NDArray} of the logical XOR operation applied to the elements of * the {@link NDArray} a and {@link NDArray} b */ public static NDArray logicalXor(NDArray a, NDArray b) { return a.logicalXor(b); } /** * Returns element-wise inverse gauss error function of the input {@code NDArray}. * *

Examples * *

     * jshell> NDArray array = manager.create(new float[] {0f, 0.5f, -1f});
     * jshell> NDArrays.erfinv(array);
     * ND: (3) cpu() float32
     * [0., 0.4769, -inf]
     * 
* * @param input The input {@code NDArray} * @return The inverse of gauss error of the input, element-wise */ public static NDArray erfinv(NDArray input) { return input.erfinv(); } }




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