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The Apache Commons Math project is a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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 org.apache.commons.math3.linear;

import java.io.Serializable;
import java.util.Arrays;

import org.apache.commons.math3.Field;
import org.apache.commons.math3.FieldElement;
import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.MathArithmeticException;
import org.apache.commons.math3.exception.NotPositiveException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.exception.NumberIsTooLargeException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.exception.OutOfRangeException;
import org.apache.commons.math3.exception.ZeroException;
import org.apache.commons.math3.exception.util.LocalizedFormats;
import org.apache.commons.math3.util.MathArrays;
import org.apache.commons.math3.util.MathUtils;

/**
 * This class implements the {@link FieldVector} interface with a {@link FieldElement} array.
 * @param  the type of the field elements
 * @since 2.0
 */
public class ArrayFieldVector> implements FieldVector, Serializable {
    /** Serializable version identifier. */
    private static final long serialVersionUID = 7648186910365927050L;

    /** Entries of the vector. */
    private T[] data;

    /** Field to which the elements belong. */
    private final Field field;

    /**
     * Build a 0-length vector.
     * Zero-length vectors may be used to initialize construction of vectors
     * by data gathering. We start with zero-length and use either the {@link
     * #ArrayFieldVector(ArrayFieldVector, ArrayFieldVector)} constructor
     * or one of the {@code append} methods ({@link #add(FieldVector)} or
     * {@link #append(ArrayFieldVector)}) to gather data into this vector.
     *
     * @param field field to which the elements belong
     */
    public ArrayFieldVector(final Field field) {
        this(field, 0);
    }

    /**
     * Construct a vector of zeroes.
     *
     * @param field Field to which the elements belong.
     * @param size Size of the vector.
     */
    public ArrayFieldVector(Field field, int size) {
        this.field = field;
        this.data  = MathArrays.buildArray(field, size);
    }

    /**
     * Construct a vector with preset values.
     *
     * @param size Size of the vector.
     * @param preset All entries will be set with this value.
     */
    public ArrayFieldVector(int size, T preset) {
        this(preset.getField(), size);
        Arrays.fill(data, preset);
    }

    /**
     * Construct a vector from an array, copying the input array.
     * This constructor needs a non-empty {@code d} array to retrieve
     * the field from its first element. This implies it cannot build
     * 0 length vectors. To build vectors from any size, one should
     * use the {@link #ArrayFieldVector(Field, FieldElement[])} constructor.
     *
     * @param d Array.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @throws ZeroException if {@code d} is empty.
     * @see #ArrayFieldVector(Field, FieldElement[])
     */
    public ArrayFieldVector(T[] d)
            throws NullArgumentException, ZeroException {
        MathUtils.checkNotNull(d);
        try {
            field = d[0].getField();
            data = d.clone();
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ZeroException(LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT);
        }
    }

    /**
     * Construct a vector from an array, copying the input array.
     *
     * @param field Field to which the elements belong.
     * @param d Array.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @see #ArrayFieldVector(FieldElement[])
     */
    public ArrayFieldVector(Field field, T[] d)
            throws NullArgumentException {
        MathUtils.checkNotNull(d);
        this.field = field;
        data = d.clone();
    }

    /**
     * Create a new ArrayFieldVector using the input array as the underlying
     * data array.
     * If an array is built specially in order to be embedded in a
     * ArrayFieldVector and not used directly, the {@code copyArray} may be
     * set to {@code false}. This will prevent the copying and improve
     * performance as no new array will be built and no data will be copied.
     * This constructor needs a non-empty {@code d} array to retrieve
     * the field from its first element. This implies it cannot build
     * 0 length vectors. To build vectors from any size, one should
     * use the {@link #ArrayFieldVector(Field, FieldElement[], boolean)}
     * constructor.
     *
     * @param d Data for the new vector.
     * @param copyArray If {@code true}, the input array will be copied,
     * otherwise it will be referenced.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @throws ZeroException if {@code d} is empty.
     * @see #ArrayFieldVector(FieldElement[])
     * @see #ArrayFieldVector(Field, FieldElement[], boolean)
     */
    public ArrayFieldVector(T[] d, boolean copyArray)
            throws NullArgumentException, ZeroException {
        MathUtils.checkNotNull(d);
        if (d.length == 0) {
            throw new ZeroException(LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT);
        }
        field = d[0].getField();
        data = copyArray ? d.clone() : d;
    }

    /**
     * Create a new ArrayFieldVector using the input array as the underlying
     * data array.
     * If an array is built specially in order to be embedded in a
     * ArrayFieldVector and not used directly, the {@code copyArray} may be
     * set to {@code false}. This will prevent the copying and improve
     * performance as no new array will be built and no data will be copied.
     *
     * @param field Field to which the elements belong.
     * @param d Data for the new vector.
     * @param copyArray If {@code true}, the input array will be copied,
     * otherwise it will be referenced.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @see #ArrayFieldVector(FieldElement[], boolean)
     */
    public ArrayFieldVector(Field field, T[] d, boolean copyArray)
            throws NullArgumentException {
        MathUtils.checkNotNull(d);
        this.field = field;
        data = copyArray ? d.clone() :  d;
    }

    /**
     * Construct a vector from part of a array.
     *
     * @param d Array.
     * @param pos Position of the first entry.
     * @param size Number of entries to copy.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @throws NumberIsTooLargeException if the size of {@code d} is less
     * than {@code pos + size}.
     */
    public ArrayFieldVector(T[] d, int pos, int size)
            throws NullArgumentException, NumberIsTooLargeException {
        MathUtils.checkNotNull(d);
        if (d.length < pos + size) {
            throw new NumberIsTooLargeException(pos + size, d.length, true);
        }
        field = d[0].getField();
        data = MathArrays.buildArray(field, size);
        System.arraycopy(d, pos, data, 0, size);
    }

    /**
     * Construct a vector from part of a array.
     *
     * @param field Field to which the elements belong.
     * @param d Array.
     * @param pos Position of the first entry.
     * @param size Number of entries to copy.
     * @throws NullArgumentException if {@code d} is {@code null}.
     * @throws NumberIsTooLargeException if the size of {@code d} is less
     * than {@code pos + size}.
     */
    public ArrayFieldVector(Field field, T[] d, int pos, int size)
            throws NullArgumentException, NumberIsTooLargeException {
        MathUtils.checkNotNull(d);
        if (d.length < pos + size) {
            throw new NumberIsTooLargeException(pos + size, d.length, true);
        }
        this.field = field;
        data = MathArrays.buildArray(field, size);
        System.arraycopy(d, pos, data, 0, size);
    }

    /**
     * Construct a vector from another vector, using a deep copy.
     *
     * @param v Vector to copy.
     * @throws NullArgumentException if {@code v} is {@code null}.
     */
    public ArrayFieldVector(FieldVector v)
            throws NullArgumentException {
        MathUtils.checkNotNull(v);
        field = v.getField();
        data = MathArrays.buildArray(field, v.getDimension());
        for (int i = 0; i < data.length; ++i) {
            data[i] = v.getEntry(i);
        }
    }

    /**
     * Construct a vector from another vector, using a deep copy.
     *
     * @param v Vector to copy.
     * @throws NullArgumentException if {@code v} is {@code null}.
     */
    public ArrayFieldVector(ArrayFieldVector v)
            throws NullArgumentException {
        MathUtils.checkNotNull(v);
        field = v.getField();
        data = v.data.clone();
    }

    /**
     * Construct a vector from another vector.
     *
     * @param v Vector to copy.
     * @param deep If {@code true} perform a deep copy, otherwise perform
     * a shallow copy
     * @throws NullArgumentException if {@code v} is {@code null}.
     */
    public ArrayFieldVector(ArrayFieldVector v, boolean deep)
            throws NullArgumentException {
        MathUtils.checkNotNull(v);
        field = v.getField();
        data = deep ? v.data.clone() : v.data;
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @deprecated as of 3.2, replaced by {@link #ArrayFieldVector(FieldVector, FieldVector)}
     */
    @Deprecated
    public ArrayFieldVector(ArrayFieldVector v1, ArrayFieldVector v2)
            throws NullArgumentException {
        this((FieldVector) v1, (FieldVector) v2);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @since 3.2
     */
    public ArrayFieldVector(FieldVector v1, FieldVector v2)
            throws NullArgumentException {
        MathUtils.checkNotNull(v1);
        MathUtils.checkNotNull(v2);
        field = v1.getField();
        final T[] v1Data =
                (v1 instanceof ArrayFieldVector) ? ((ArrayFieldVector) v1).data : v1.toArray();
        final T[] v2Data =
                (v2 instanceof ArrayFieldVector) ? ((ArrayFieldVector) v2).data : v2.toArray();
        data = MathArrays.buildArray(field, v1Data.length + v2Data.length);
        System.arraycopy(v1Data, 0, data, 0, v1Data.length);
        System.arraycopy(v2Data, 0, data, v1Data.length, v2Data.length);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @deprecated as of 3.2, replaced by {@link #ArrayFieldVector(FieldVector, FieldElement[])}
     */
    @Deprecated
    public ArrayFieldVector(ArrayFieldVector v1, T[] v2)
            throws NullArgumentException {
        this((FieldVector) v1, v2);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @since 3.2
     */
    public ArrayFieldVector(FieldVector v1, T[] v2)
            throws NullArgumentException {
        MathUtils.checkNotNull(v1);
        MathUtils.checkNotNull(v2);
        field = v1.getField();
        final T[] v1Data =
                (v1 instanceof ArrayFieldVector) ? ((ArrayFieldVector) v1).data : v1.toArray();
        data = MathArrays.buildArray(field, v1Data.length + v2.length);
        System.arraycopy(v1Data, 0, data, 0, v1Data.length);
        System.arraycopy(v2, 0, data, v1Data.length, v2.length);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @deprecated as of 3.2, replaced by {@link #ArrayFieldVector(FieldElement[], FieldVector)}
     */
    @Deprecated
    public ArrayFieldVector(T[] v1, ArrayFieldVector v2)
            throws NullArgumentException {
        this(v1, (FieldVector) v2);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @since 3.2
     */
    public ArrayFieldVector(T[] v1, FieldVector v2)
            throws NullArgumentException {
        MathUtils.checkNotNull(v1);
        MathUtils.checkNotNull(v2);
        field = v2.getField();
        final T[] v2Data =
                (v2 instanceof ArrayFieldVector) ? ((ArrayFieldVector) v2).data : v2.toArray();
        data = MathArrays.buildArray(field, v1.length + v2Data.length);
        System.arraycopy(v1, 0, data, 0, v1.length);
        System.arraycopy(v2Data, 0, data, v1.length, v2Data.length);
    }

    /**
     * Construct a vector by appending one vector to another vector.
     * This constructor needs at least one non-empty array to retrieve
     * the field from its first element. This implies it cannot build
     * 0 length vectors. To build vectors from any size, one should
     * use the {@link #ArrayFieldVector(Field, FieldElement[], FieldElement[])}
     * constructor.
     *
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @throws ZeroException if both arrays are empty.
     * @see #ArrayFieldVector(Field, FieldElement[], FieldElement[])
     */
    public ArrayFieldVector(T[] v1, T[] v2)
            throws NullArgumentException, ZeroException {
        MathUtils.checkNotNull(v1);
        MathUtils.checkNotNull(v2);
        if (v1.length + v2.length == 0) {
            throw new ZeroException(LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT);
        }
        data = MathArrays.buildArray(v1[0].getField(), v1.length + v2.length);
        System.arraycopy(v1, 0, data, 0, v1.length);
        System.arraycopy(v2, 0, data, v1.length, v2.length);
        field = data[0].getField();
    }

    /**
     * Construct a vector by appending one vector to another vector.
     *
     * @param field Field to which the elements belong.
     * @param v1 First vector (will be put in front of the new vector).
     * @param v2 Second vector (will be put at back of the new vector).
     * @throws NullArgumentException if {@code v1} or {@code v2} is
     * {@code null}.
     * @throws ZeroException if both arrays are empty.
     * @see #ArrayFieldVector(FieldElement[], FieldElement[])
     */
    public ArrayFieldVector(Field field, T[] v1, T[] v2)
            throws NullArgumentException, ZeroException {
        MathUtils.checkNotNull(v1);
        MathUtils.checkNotNull(v2);
        if (v1.length + v2.length == 0) {
            throw new ZeroException(LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT);
        }
        data = MathArrays.buildArray(field, v1.length + v2.length);
        System.arraycopy(v1, 0, data, 0, v1.length);
        System.arraycopy(v2, 0, data, v1.length, v2.length);
        this.field = field;
    }

    /** {@inheritDoc} */
    public Field getField() {
        return field;
    }

    /** {@inheritDoc} */
    public FieldVector copy() {
        return new ArrayFieldVector(this, true);
    }

    /** {@inheritDoc} */
    public FieldVector add(FieldVector v)
        throws DimensionMismatchException {
        try {
            return add((ArrayFieldVector) v);
        } catch (ClassCastException cce) {
            checkVectorDimensions(v);
            T[] out = MathArrays.buildArray(field, data.length);
            for (int i = 0; i < data.length; i++) {
                out[i] = data[i].add(v.getEntry(i));
            }
            return new ArrayFieldVector(field, out, false);
        }
    }

    /**
     * Compute the sum of {@code this} and {@code v}.
     * @param v vector to be added
     * @return {@code this + v}
     * @throws DimensionMismatchException if {@code v} is not the same size as
     * {@code this}
     */
    public ArrayFieldVector add(ArrayFieldVector v)
        throws DimensionMismatchException {
        checkVectorDimensions(v.data.length);
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].add(v.data[i]);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector subtract(FieldVector v)
        throws DimensionMismatchException {
        try {
            return subtract((ArrayFieldVector) v);
        } catch (ClassCastException cce) {
            checkVectorDimensions(v);
            T[] out = MathArrays.buildArray(field, data.length);
            for (int i = 0; i < data.length; i++) {
                out[i] = data[i].subtract(v.getEntry(i));
            }
            return new ArrayFieldVector(field, out, false);
        }
    }

    /**
     * Compute {@code this} minus {@code v}.
     * @param v vector to be subtracted
     * @return {@code this - v}
     * @throws DimensionMismatchException if {@code v} is not the same size as
     * {@code this}
     */
    public ArrayFieldVector subtract(ArrayFieldVector v)
        throws DimensionMismatchException {
        checkVectorDimensions(v.data.length);
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].subtract(v.data[i]);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapAdd(T d) throws NullArgumentException {
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].add(d);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapAddToSelf(T d) throws NullArgumentException {
        for (int i = 0; i < data.length; i++) {
            data[i] = data[i].add(d);
        }
        return this;
    }

    /** {@inheritDoc} */
    public FieldVector mapSubtract(T d) throws NullArgumentException {
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].subtract(d);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapSubtractToSelf(T d) throws NullArgumentException {
        for (int i = 0; i < data.length; i++) {
            data[i] = data[i].subtract(d);
        }
        return this;
    }

    /** {@inheritDoc} */
    public FieldVector mapMultiply(T d) throws NullArgumentException {
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].multiply(d);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapMultiplyToSelf(T d) throws NullArgumentException {
        for (int i = 0; i < data.length; i++) {
            data[i] = data[i].multiply(d);
        }
        return this;
    }

    /** {@inheritDoc} */
    public FieldVector mapDivide(T d)
        throws NullArgumentException, MathArithmeticException {
        MathUtils.checkNotNull(d);
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].divide(d);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapDivideToSelf(T d)
        throws NullArgumentException, MathArithmeticException {
        MathUtils.checkNotNull(d);
        for (int i = 0; i < data.length; i++) {
            data[i] = data[i].divide(d);
        }
        return this;
    }

    /** {@inheritDoc} */
    public FieldVector mapInv() throws MathArithmeticException {
        T[] out = MathArrays.buildArray(field, data.length);
        final T one = field.getOne();
        for (int i = 0; i < data.length; i++) {
            try {
                out[i] = one.divide(data[i]);
            } catch (final MathArithmeticException e) {
                throw new MathArithmeticException(LocalizedFormats.INDEX, i);
            }
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector mapInvToSelf() throws MathArithmeticException {
        final T one = field.getOne();
        for (int i = 0; i < data.length; i++) {
            try {
                data[i] = one.divide(data[i]);
            } catch (final MathArithmeticException e) {
                throw new MathArithmeticException(LocalizedFormats.INDEX, i);
            }
        }
        return this;
    }

    /** {@inheritDoc} */
    public FieldVector ebeMultiply(FieldVector v)
        throws DimensionMismatchException {
        try {
            return ebeMultiply((ArrayFieldVector) v);
        } catch (ClassCastException cce) {
            checkVectorDimensions(v);
            T[] out = MathArrays.buildArray(field, data.length);
            for (int i = 0; i < data.length; i++) {
                out[i] = data[i].multiply(v.getEntry(i));
            }
            return new ArrayFieldVector(field, out, false);
        }
    }

    /**
     * Element-by-element multiplication.
     * @param v vector by which instance elements must be multiplied
     * @return a vector containing {@code this[i] * v[i]} for all {@code i}
     * @throws DimensionMismatchException if {@code v} is not the same size as
     * {@code this}
     */
    public ArrayFieldVector ebeMultiply(ArrayFieldVector v)
        throws DimensionMismatchException {
        checkVectorDimensions(v.data.length);
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            out[i] = data[i].multiply(v.data[i]);
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public FieldVector ebeDivide(FieldVector v)
        throws DimensionMismatchException, MathArithmeticException {
        try {
            return ebeDivide((ArrayFieldVector) v);
        } catch (ClassCastException cce) {
            checkVectorDimensions(v);
            T[] out = MathArrays.buildArray(field, data.length);
            for (int i = 0; i < data.length; i++) {
                try {
                    out[i] = data[i].divide(v.getEntry(i));
                } catch (final MathArithmeticException e) {
                    throw new MathArithmeticException(LocalizedFormats.INDEX, i);
                }
            }
            return new ArrayFieldVector(field, out, false);
        }
    }

    /**
     * Element-by-element division.
     * @param v vector by which instance elements must be divided
     * @return a vector containing {@code this[i] / v[i]} for all {@code i}
     * @throws DimensionMismatchException if {@code v} is not the same size as
     * {@code this}
     * @throws MathArithmeticException if one entry of {@code v} is zero.
     */
    public ArrayFieldVector ebeDivide(ArrayFieldVector v)
        throws DimensionMismatchException, MathArithmeticException {
        checkVectorDimensions(v.data.length);
        T[] out = MathArrays.buildArray(field, data.length);
        for (int i = 0; i < data.length; i++) {
            try {
                out[i] = data[i].divide(v.data[i]);
            } catch (final MathArithmeticException e) {
                throw new MathArithmeticException(LocalizedFormats.INDEX, i);
            }
        }
        return new ArrayFieldVector(field, out, false);
    }

    /** {@inheritDoc} */
    public T[] getData() {
        return data.clone();
    }

    /**
     * Returns a reference to the underlying data array.
     * 

Does not make a fresh copy of the underlying data.

* @return array of entries */ public T[] getDataRef() { return data; } /** {@inheritDoc} */ public T dotProduct(FieldVector v) throws DimensionMismatchException { try { return dotProduct((ArrayFieldVector) v); } catch (ClassCastException cce) { checkVectorDimensions(v); T dot = field.getZero(); for (int i = 0; i < data.length; i++) { dot = dot.add(data[i].multiply(v.getEntry(i))); } return dot; } } /** * Compute the dot product. * @param v vector with which dot product should be computed * @return the scalar dot product of {@code this} and {@code v} * @throws DimensionMismatchException if {@code v} is not the same size as * {@code this} */ public T dotProduct(ArrayFieldVector v) throws DimensionMismatchException { checkVectorDimensions(v.data.length); T dot = field.getZero(); for (int i = 0; i < data.length; i++) { dot = dot.add(data[i].multiply(v.data[i])); } return dot; } /** {@inheritDoc} */ public FieldVector projection(FieldVector v) throws DimensionMismatchException, MathArithmeticException { return v.mapMultiply(dotProduct(v).divide(v.dotProduct(v))); } /** Find the orthogonal projection of this vector onto another vector. * @param v vector onto which {@code this} must be projected * @return projection of {@code this} onto {@code v} * @throws DimensionMismatchException if {@code v} is not the same size as * {@code this} * @throws MathArithmeticException if {@code v} is the null vector. */ public ArrayFieldVector projection(ArrayFieldVector v) throws DimensionMismatchException, MathArithmeticException { return (ArrayFieldVector) v.mapMultiply(dotProduct(v).divide(v.dotProduct(v))); } /** {@inheritDoc} */ public FieldMatrix outerProduct(FieldVector v) { try { return outerProduct((ArrayFieldVector) v); } catch (ClassCastException cce) { final int m = data.length; final int n = v.getDimension(); final FieldMatrix out = new Array2DRowFieldMatrix(field, m, n); for (int i = 0; i < m; i++) { for (int j = 0; j < n; j++) { out.setEntry(i, j, data[i].multiply(v.getEntry(j))); } } return out; } } /** * Compute the outer product. * @param v vector with which outer product should be computed * @return the matrix outer product between instance and v */ public FieldMatrix outerProduct(ArrayFieldVector v) { final int m = data.length; final int n = v.data.length; final FieldMatrix out = new Array2DRowFieldMatrix(field, m, n); for (int i = 0; i < m; i++) { for (int j = 0; j < n; j++) { out.setEntry(i, j, data[i].multiply(v.data[j])); } } return out; } /** {@inheritDoc} */ public T getEntry(int index) { return data[index]; } /** {@inheritDoc} */ public int getDimension() { return data.length; } /** {@inheritDoc} */ public FieldVector append(FieldVector v) { try { return append((ArrayFieldVector) v); } catch (ClassCastException cce) { return new ArrayFieldVector(this,new ArrayFieldVector(v)); } } /** * Construct a vector by appending a vector to this vector. * @param v vector to append to this one. * @return a new vector */ public ArrayFieldVector append(ArrayFieldVector v) { return new ArrayFieldVector(this, v); } /** {@inheritDoc} */ public FieldVector append(T in) { final T[] out = MathArrays.buildArray(field, data.length + 1); System.arraycopy(data, 0, out, 0, data.length); out[data.length] = in; return new ArrayFieldVector(field, out, false); } /** {@inheritDoc} */ public FieldVector getSubVector(int index, int n) throws OutOfRangeException, NotPositiveException { if (n < 0) { throw new NotPositiveException(LocalizedFormats.NUMBER_OF_ELEMENTS_SHOULD_BE_POSITIVE, n); } ArrayFieldVector out = new ArrayFieldVector(field, n); try { System.arraycopy(data, index, out.data, 0, n); } catch (IndexOutOfBoundsException e) { checkIndex(index); checkIndex(index + n - 1); } return out; } /** {@inheritDoc} */ public void setEntry(int index, T value) { try { data[index] = value; } catch (IndexOutOfBoundsException e) { checkIndex(index); } } /** {@inheritDoc} */ public void setSubVector(int index, FieldVector v) throws OutOfRangeException { try { try { set(index, (ArrayFieldVector) v); } catch (ClassCastException cce) { for (int i = index; i < index + v.getDimension(); ++i) { data[i] = v.getEntry(i-index); } } } catch (IndexOutOfBoundsException e) { checkIndex(index); checkIndex(index + v.getDimension() - 1); } } /** * Set a set of consecutive elements. * * @param index index of first element to be set. * @param v vector containing the values to set. * @throws OutOfRangeException if the index is invalid. */ public void set(int index, ArrayFieldVector v) throws OutOfRangeException { try { System.arraycopy(v.data, 0, data, index, v.data.length); } catch (IndexOutOfBoundsException e) { checkIndex(index); checkIndex(index + v.data.length - 1); } } /** {@inheritDoc} */ public void set(T value) { Arrays.fill(data, value); } /** {@inheritDoc} */ public T[] toArray(){ return data.clone(); } /** * Check if instance and specified vectors have the same dimension. * @param v vector to compare instance with * @exception DimensionMismatchException if the vectors do not * have the same dimensions */ protected void checkVectorDimensions(FieldVector v) throws DimensionMismatchException { checkVectorDimensions(v.getDimension()); } /** * Check if instance dimension is equal to some expected value. * * @param n Expected dimension. * @throws DimensionMismatchException if the dimension is not equal to the * size of {@code this} vector. */ protected void checkVectorDimensions(int n) throws DimensionMismatchException { if (data.length != n) { throw new DimensionMismatchException(data.length, n); } } /** * Visits (but does not alter) all entries of this vector in default order * (increasing index). * * @param visitor the visitor to be used to process the entries of this * vector * @return the value returned by {@link FieldVectorPreservingVisitor#end()} * at the end of the walk * @since 3.3 */ public T walkInDefaultOrder(final FieldVectorPreservingVisitor visitor) { final int dim = getDimension(); visitor.start(dim, 0, dim - 1); for (int i = 0; i < dim; i++) { visitor.visit(i, getEntry(i)); } return visitor.end(); } /** * Visits (but does not alter) some entries of this vector in default order * (increasing index). * * @param visitor visitor to be used to process the entries of this vector * @param start the index of the first entry to be visited * @param end the index of the last entry to be visited (inclusive) * @return the value returned by {@link FieldVectorPreservingVisitor#end()} * at the end of the walk * @throws NumberIsTooSmallException if {@code end < start}. * @throws OutOfRangeException if the indices are not valid. * @since 3.3 */ public T walkInDefaultOrder(final FieldVectorPreservingVisitor visitor, final int start, final int end) throws NumberIsTooSmallException, OutOfRangeException { checkIndices(start, end); visitor.start(getDimension(), start, end); for (int i = start; i <= end; i++) { visitor.visit(i, getEntry(i)); } return visitor.end(); } /** * Visits (but does not alter) all entries of this vector in optimized * order. The order in which the entries are visited is selected so as to * lead to the most efficient implementation; it might depend on the * concrete implementation of this abstract class. * * @param visitor the visitor to be used to process the entries of this * vector * @return the value returned by {@link FieldVectorPreservingVisitor#end()} * at the end of the walk * @since 3.3 */ public T walkInOptimizedOrder(final FieldVectorPreservingVisitor visitor) { return walkInDefaultOrder(visitor); } /** * Visits (but does not alter) some entries of this vector in optimized * order. The order in which the entries are visited is selected so as to * lead to the most efficient implementation; it might depend on the * concrete implementation of this abstract class. * * @param visitor visitor to be used to process the entries of this vector * @param start the index of the first entry to be visited * @param end the index of the last entry to be visited (inclusive) * @return the value returned by {@link FieldVectorPreservingVisitor#end()} * at the end of the walk * @throws NumberIsTooSmallException if {@code end < start}. * @throws OutOfRangeException if the indices are not valid. * @since 3.3 */ public T walkInOptimizedOrder(final FieldVectorPreservingVisitor visitor, final int start, final int end) throws NumberIsTooSmallException, OutOfRangeException { return walkInDefaultOrder(visitor, start, end); } /** * Visits (and possibly alters) all entries of this vector in default order * (increasing index). * * @param visitor the visitor to be used to process and modify the entries * of this vector * @return the value returned by {@link FieldVectorChangingVisitor#end()} * at the end of the walk * @since 3.3 */ public T walkInDefaultOrder(final FieldVectorChangingVisitor visitor) { final int dim = getDimension(); visitor.start(dim, 0, dim - 1); for (int i = 0; i < dim; i++) { setEntry(i, visitor.visit(i, getEntry(i))); } return visitor.end(); } /** * Visits (and possibly alters) some entries of this vector in default order * (increasing index). * * @param visitor visitor to be used to process the entries of this vector * @param start the index of the first entry to be visited * @param end the index of the last entry to be visited (inclusive) * @return the value returned by {@link FieldVectorChangingVisitor#end()} * at the end of the walk * @throws NumberIsTooSmallException if {@code end < start}. * @throws OutOfRangeException if the indices are not valid. * @since 3.3 */ public T walkInDefaultOrder(final FieldVectorChangingVisitor visitor, final int start, final int end) throws NumberIsTooSmallException, OutOfRangeException { checkIndices(start, end); visitor.start(getDimension(), start, end); for (int i = start; i <= end; i++) { setEntry(i, visitor.visit(i, getEntry(i))); } return visitor.end(); } /** * Visits (and possibly alters) all entries of this vector in optimized * order. The order in which the entries are visited is selected so as to * lead to the most efficient implementation; it might depend on the * concrete implementation of this abstract class. * * @param visitor the visitor to be used to process the entries of this * vector * @return the value returned by {@link FieldVectorChangingVisitor#end()} * at the end of the walk * @since 3.3 */ public T walkInOptimizedOrder(final FieldVectorChangingVisitor visitor) { return walkInDefaultOrder(visitor); } /** * Visits (and possibly change) some entries of this vector in optimized * order. The order in which the entries are visited is selected so as to * lead to the most efficient implementation; it might depend on the * concrete implementation of this abstract class. * * @param visitor visitor to be used to process the entries of this vector * @param start the index of the first entry to be visited * @param end the index of the last entry to be visited (inclusive) * @return the value returned by {@link FieldVectorChangingVisitor#end()} * at the end of the walk * @throws NumberIsTooSmallException if {@code end < start}. * @throws OutOfRangeException if the indices are not valid. * @since 3.3 */ public T walkInOptimizedOrder(final FieldVectorChangingVisitor visitor, final int start, final int end) throws NumberIsTooSmallException, OutOfRangeException { return walkInDefaultOrder(visitor, start, end); } /** * Test for the equality of two vectors. * * @param other Object to test for equality. * @return {@code true} if two vector objects are equal, {@code false} * otherwise. */ @Override public boolean equals(Object other) { if (this == other) { return true; } if (other == null) { return false; } try { @SuppressWarnings("unchecked") // May fail, but we ignore ClassCastException FieldVector rhs = (FieldVector) other; if (data.length != rhs.getDimension()) { return false; } for (int i = 0; i < data.length; ++i) { if (!data[i].equals(rhs.getEntry(i))) { return false; } } return true; } catch (ClassCastException ex) { // ignore exception return false; } } /** * Get a hashCode for the real vector. *

All NaN values have the same hash code.

* @return a hash code value for this object */ @Override public int hashCode() { int h = 3542; for (final T a : data) { h ^= a.hashCode(); } return h; } /** * Check if an index is valid. * * @param index Index to check. * @exception OutOfRangeException if the index is not valid. */ private void checkIndex(final int index) throws OutOfRangeException { if (index < 0 || index >= getDimension()) { throw new OutOfRangeException(LocalizedFormats.INDEX, index, 0, getDimension() - 1); } } /** * Checks that the indices of a subvector are valid. * * @param start the index of the first entry of the subvector * @param end the index of the last entry of the subvector (inclusive) * @throws OutOfRangeException if {@code start} of {@code end} are not valid * @throws NumberIsTooSmallException if {@code end < start} * @since 3.3 */ private void checkIndices(final int start, final int end) throws NumberIsTooSmallException, OutOfRangeException { final int dim = getDimension(); if ((start < 0) || (start >= dim)) { throw new OutOfRangeException(LocalizedFormats.INDEX, start, 0, dim - 1); } if ((end < 0) || (end >= dim)) { throw new OutOfRangeException(LocalizedFormats.INDEX, end, 0, dim - 1); } if (end < start) { throw new NumberIsTooSmallException(LocalizedFormats.INITIAL_ROW_AFTER_FINAL_ROW, end, start, false); } } }




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