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Diffstat (limited to 'src/main/java/org/apache/commons/math/linear/ArrayFieldVector.java')
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1 files changed, 869 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/linear/ArrayFieldVector.java b/src/main/java/org/apache/commons/math/linear/ArrayFieldVector.java new file mode 100644 index 0000000..eefce2f --- /dev/null +++ b/src/main/java/org/apache/commons/math/linear/ArrayFieldVector.java @@ -0,0 +1,869 @@ +/* + * 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.math.linear; + +import java.io.Serializable; +import java.lang.reflect.Array; +import java.util.Arrays; + +import org.apache.commons.math.Field; +import org.apache.commons.math.FieldElement; +import org.apache.commons.math.MathRuntimeException; +import org.apache.commons.math.exception.util.LocalizedFormats; + +/** + * This class implements the {@link FieldVector} interface with a {@link FieldElement} array. + * @param <T> the type of the field elements + * @version $Revision: 1003997 $ $Date: 2010-10-03 18:45:55 +0200 (dim. 03 oct. 2010) $ + * @since 2.0 + */ +public class ArrayFieldVector<T extends FieldElement<T>> implements FieldVector<T>, Serializable { + + /** Serializable version identifier. */ + private static final long serialVersionUID = 7648186910365927050L; + + /** Entries of the vector. */ + protected T[] data; + + /** Field to which the elements belong. */ + private final Field<T> field; + + /** + * Build a 0-length vector. + * <p>Zero-length vectors may be used to initialized 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</code> methods ({@link #append(FieldElement[])}, + * {@link #add(FieldVector)}, {@link #append(ArrayFieldVector)}) to gather data + * into this vector.</p> + * @param field field to which the elements belong + */ + public ArrayFieldVector(final Field<T> field) { + this(field, 0); + } + + /** + * Construct a (size)-length vector of zeros. + * @param field field to which the elements belong + * @param size size of the vector + */ + public ArrayFieldVector(Field<T> field, int size) { + this.field = field; + data = buildArray(size); + Arrays.fill(data, field.getZero()); + } + + /** + * Construct an (size)-length vector with preset values. + * @param size size of the vector + * @param preset fill the vector with this scalar 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. + * <p> + * 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. + * </p> + * @param d array of Ts. + * @throws IllegalArgumentException if <code>d</code> is empty + * @see #ArrayFieldVector(Field, FieldElement[]) + */ + public ArrayFieldVector(T[] d) + throws IllegalArgumentException { + try { + field = d[0].getField(); + data = d.clone(); + } catch (ArrayIndexOutOfBoundsException e) { + throw MathRuntimeException.createIllegalArgumentException( + 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 of Ts. + * @see #ArrayFieldVector(FieldElement[]) + */ + public ArrayFieldVector(Field<T> field, T[] d) { + this.field = field; + data = d.clone(); + } + + /** + * Create a new ArrayFieldVector using the input array as the underlying + * data array. + * <p>If an array is built specially in order to be embedded in a + * ArrayFieldVector and not used directly, the <code>copyArray</code> may be + * set to <code>false</code. This will prevent the copying and improve + * performance as no new array will be built and no data will be copied.</p> + * <p> + * 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. + * </p> + * @param d data for new vector + * @param copyArray if true, the input array will be copied, otherwise + * it will be referenced + * @throws IllegalArgumentException if <code>d</code> is empty + * @throws NullPointerException if <code>d</code> is null + * @see #ArrayFieldVector(FieldElement[]) + * @see #ArrayFieldVector(Field, FieldElement[], boolean) + */ + public ArrayFieldVector(T[] d, boolean copyArray) + throws NullPointerException, IllegalArgumentException { + if (d.length == 0) { + throw MathRuntimeException.createIllegalArgumentException( + 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. + * <p>If an array is built specially in order to be embedded in a + * ArrayFieldVector and not used directly, the <code>copyArray</code> may be + * set to <code>false</code. This will prevent the copying and improve + * performance as no new array will be built and no data will be copied.</p> + * @param field field to which the elements belong + * @param d data for new vector + * @param copyArray if true, the input array will be copied, otherwise + * it will be referenced + * @see #ArrayFieldVector(FieldElement[], boolean) + */ + public ArrayFieldVector(Field<T> field, T[] d, boolean copyArray) { + this.field = field; + data = copyArray ? d.clone() : d; + } + + /** + * Construct a vector from part of a array. + * @param d array of Ts. + * @param pos position of first entry + * @param size number of entries to copy + */ + public ArrayFieldVector(T[] d, int pos, int size) { + if (d.length < pos + size) { + throw MathRuntimeException.createIllegalArgumentException( + LocalizedFormats.POSITION_SIZE_MISMATCH_INPUT_ARRAY, + pos, size, d.length); + } + field = d[0].getField(); + data = buildArray(size); + System.arraycopy(d, pos, data, 0, size); + } + + /** + * Construct a vector from another vector, using a deep copy. + * @param v vector to copy + */ + public ArrayFieldVector(FieldVector<T> v) { + field = v.getField(); + data = buildArray(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 + */ + public ArrayFieldVector(ArrayFieldVector<T> v) { + field = v.getField(); + data = v.data.clone(); + } + + /** + * Construct a vector from another vector. + * @param v vector to copy + * @param deep if true perform a deep copy otherwise perform a shallow copy + */ + public ArrayFieldVector(ArrayFieldVector<T> v, boolean deep) { + 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) + */ + public ArrayFieldVector(ArrayFieldVector<T> v1, ArrayFieldVector<T> v2) { + field = v1.getField(); + data = buildArray(v1.data.length + v2.data.length); + System.arraycopy(v1.data, 0, data, 0, v1.data.length); + System.arraycopy(v2.data, 0, data, v1.data.length, v2.data.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) + */ + public ArrayFieldVector(ArrayFieldVector<T> v1, T[] v2) { + field = v1.getField(); + data = buildArray(v1.data.length + v2.length); + System.arraycopy(v1.data, 0, data, 0, v1.data.length); + System.arraycopy(v2, 0, data, v1.data.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) + */ + public ArrayFieldVector(T[] v1, ArrayFieldVector<T> v2) { + field = v2.getField(); + data = buildArray(v1.length + v2.data.length); + System.arraycopy(v1, 0, data, 0, v1.length); + System.arraycopy(v2.data, 0, data, v1.length, v2.data.length); + } + + /** + * Construct a vector by appending one vector to another vector. + * <p> + * 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. + * </p> + * @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) + * @exception IllegalArgumentException if both vectors are empty + * @see #ArrayFieldVector(Field, FieldElement[], FieldElement[]) + */ + public ArrayFieldVector(T[] v1, T[] v2) { + try { + data = buildArray(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(); + } catch (ArrayIndexOutOfBoundsException e) { + throw MathRuntimeException.createIllegalArgumentException( + LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT); + } + } + + /** + * 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) + * @see #ArrayFieldVector(FieldElement[], FieldElement[]) + */ + public ArrayFieldVector(Field<T> field, T[] v1, T[] v2) { + if (v1.length + v2.length == 0) { + throw MathRuntimeException.createIllegalArgumentException( + LocalizedFormats.VECTOR_MUST_HAVE_AT_LEAST_ONE_ELEMENT); + } + data = buildArray(v1.length + v2.length); + System.arraycopy(v1, 0, data, 0, v1.length); + System.arraycopy(v2, 0, data, v1.length, v2.length); + this.field = data[0].getField(); + } + + /** Build an array of elements. + * @param length size of the array to build + * @return a new array + */ + @SuppressWarnings("unchecked") // field is of type T + private T[] buildArray(final int length) { + return (T[]) Array.newInstance(field.getZero().getClass(), length); + } + + /** {@inheritDoc} */ + public Field<T> getField() { + return field; + } + + /** {@inheritDoc} */ + public FieldVector<T> copy() { + return new ArrayFieldVector<T>(this, true); + } + + /** {@inheritDoc} */ + public FieldVector<T> add(FieldVector<T> v) throws IllegalArgumentException { + try { + return add((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + checkVectorDimensions(v); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].add(v.getEntry(i)); + } + return new ArrayFieldVector<T>(out); + } + } + + /** {@inheritDoc} */ + public FieldVector<T> add(T[] v) throws IllegalArgumentException { + checkVectorDimensions(v.length); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].add(v[i]); + } + return new ArrayFieldVector<T>(out); + } + + /** + * Compute the sum of this and v. + * @param v vector to be added + * @return this + v + * @throws IllegalArgumentException if v is not the same size as this + */ + public ArrayFieldVector<T> add(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return (ArrayFieldVector<T>) add(v.data); + } + + /** {@inheritDoc} */ + public FieldVector<T> subtract(FieldVector<T> v) throws IllegalArgumentException { + try { + return subtract((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + checkVectorDimensions(v); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].subtract(v.getEntry(i)); + } + return new ArrayFieldVector<T>(out); + } + } + + /** {@inheritDoc} */ + public FieldVector<T> subtract(T[] v) throws IllegalArgumentException { + checkVectorDimensions(v.length); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].subtract(v[i]); + } + return new ArrayFieldVector<T>(out); + } + + /** + * Compute this minus v. + * @param v vector to be subtracted + * @return this + v + * @throws IllegalArgumentException if v is not the same size as this + */ + public ArrayFieldVector<T> subtract(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return (ArrayFieldVector<T>) subtract(v.data); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapAdd(T d) { + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].add(d); + } + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapAddToSelf(T d) { + for (int i = 0; i < data.length; i++) { + data[i] = data[i].add(d); + } + return this; + } + + /** {@inheritDoc} */ + public FieldVector<T> mapSubtract(T d) { + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].subtract(d); + } + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapSubtractToSelf(T d) { + for (int i = 0; i < data.length; i++) { + data[i] = data[i].subtract(d); + } + return this; + } + + /** {@inheritDoc} */ + public FieldVector<T> mapMultiply(T d) { + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].multiply(d); + } + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapMultiplyToSelf(T d) { + for (int i = 0; i < data.length; i++) { + data[i] = data[i].multiply(d); + } + return this; + } + + /** {@inheritDoc} */ + public FieldVector<T> mapDivide(T d) { + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].divide(d); + } + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapDivideToSelf(T d) { + for (int i = 0; i < data.length; i++) { + data[i] = data[i].divide(d); + } + return this; + } + + /** {@inheritDoc} */ + public FieldVector<T> mapInv() { + T[] out = buildArray(data.length); + final T one = field.getOne(); + for (int i = 0; i < data.length; i++) { + out[i] = one.divide(data[i]); + } + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> mapInvToSelf() { + final T one = field.getOne(); + for (int i = 0; i < data.length; i++) { + data[i] = one.divide(data[i]); + } + return this; + } + + /** {@inheritDoc} */ + public FieldVector<T> ebeMultiply(FieldVector<T> v) + throws IllegalArgumentException { + try { + return ebeMultiply((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + checkVectorDimensions(v); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].multiply(v.getEntry(i)); + } + return new ArrayFieldVector<T>(out); + } + } + + /** {@inheritDoc} */ + public FieldVector<T> ebeMultiply(T[] v) + throws IllegalArgumentException { + checkVectorDimensions(v.length); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].multiply(v[i]); + } + return new ArrayFieldVector<T>(out); + } + + /** + * Element-by-element multiplication. + * @param v vector by which instance elements must be multiplied + * @return a vector containing this[i] * v[i] for all i + * @exception IllegalArgumentException if v is not the same size as this + */ + public ArrayFieldVector<T> ebeMultiply(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return (ArrayFieldVector<T>) ebeMultiply(v.data); + } + + /** {@inheritDoc} */ + public FieldVector<T> ebeDivide(FieldVector<T> v) + throws IllegalArgumentException { + try { + return ebeDivide((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + checkVectorDimensions(v); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].divide(v.getEntry(i)); + } + return new ArrayFieldVector<T>(out); + } + } + + /** {@inheritDoc} */ + public FieldVector<T> ebeDivide(T[] v) + throws IllegalArgumentException { + checkVectorDimensions(v.length); + T[] out = buildArray(data.length); + for (int i = 0; i < data.length; i++) { + out[i] = data[i].divide(v[i]); + } + return new ArrayFieldVector<T>(out); + } + + /** + * Element-by-element division. + * @param v vector by which instance elements must be divided + * @return a vector containing this[i] / v[i] for all i + * @throws IllegalArgumentException if v is not the same size as this + */ + public ArrayFieldVector<T> ebeDivide(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return (ArrayFieldVector<T>) ebeDivide(v.data); + } + + /** {@inheritDoc} */ + public T[] getData() { + return data.clone(); + } + + /** + * Returns a reference to the underlying data array. + * <p>Does not make a fresh copy of the underlying data.</p> + * @return array of entries + */ + public T[] getDataRef() { + return data; + } + + /** {@inheritDoc} */ + public T dotProduct(FieldVector<T> v) + throws IllegalArgumentException { + try { + return dotProduct((ArrayFieldVector<T>) 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; + } + } + + /** {@inheritDoc} */ + public T dotProduct(T[] v) + throws IllegalArgumentException { + checkVectorDimensions(v.length); + T dot = field.getZero(); + for (int i = 0; i < data.length; i++) { + dot = dot.add(data[i].multiply(v[i])); + } + return dot; + } + + /** + * Compute the dot product. + * @param v vector with which dot product should be computed + * @return the scalar dot product between instance and v + * @exception IllegalArgumentException if v is not the same size as this + */ + public T dotProduct(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return dotProduct(v.data); + } + + /** {@inheritDoc} */ + public FieldVector<T> projection(FieldVector<T> v) { + return v.mapMultiply(dotProduct(v).divide(v.dotProduct(v))); + } + + /** {@inheritDoc} */ + public FieldVector<T> projection(T[] v) { + return projection(new ArrayFieldVector<T>(v, false)); + } + + /** Find the orthogonal projection of this vector onto another vector. + * @param v vector onto which instance must be projected + * @return projection of the instance onto v + * @throws IllegalArgumentException if v is not the same size as this + */ + public ArrayFieldVector<T> projection(ArrayFieldVector<T> v) { + return (ArrayFieldVector<T>) v.mapMultiply(dotProduct(v).divide(v.dotProduct(v))); + } + + /** {@inheritDoc} */ + public FieldMatrix<T> outerProduct(FieldVector<T> v) + throws IllegalArgumentException { + try { + return outerProduct((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + checkVectorDimensions(v); + final int m = data.length; + final FieldMatrix<T> out = new Array2DRowFieldMatrix<T>(field, m, m); + for (int i = 0; i < data.length; i++) { + for (int j = 0; j < data.length; 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 square matrix outer product between instance and v + * @exception IllegalArgumentException if v is not the same size as this + */ + public FieldMatrix<T> outerProduct(ArrayFieldVector<T> v) + throws IllegalArgumentException { + return outerProduct(v.data); + } + + /** {@inheritDoc} */ + public FieldMatrix<T> outerProduct(T[] v) + throws IllegalArgumentException { + checkVectorDimensions(v.length); + final int m = data.length; + final FieldMatrix<T> out = new Array2DRowFieldMatrix<T>(field, m, m); + for (int i = 0; i < data.length; i++) { + for (int j = 0; j < data.length; j++) { + out.setEntry(i, j, data[i].multiply(v[j])); + } + } + return out; + } + + /** {@inheritDoc} */ + public T getEntry(int index) throws MatrixIndexException { + return data[index]; + } + + /** {@inheritDoc} */ + public int getDimension() { + return data.length; + } + + /** {@inheritDoc} */ + public FieldVector<T> append(FieldVector<T> v) { + try { + return append((ArrayFieldVector<T>) v); + } catch (ClassCastException cce) { + return new ArrayFieldVector<T>(this,new ArrayFieldVector<T>(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<T> append(ArrayFieldVector<T> v) { + return new ArrayFieldVector<T>(this, v); + } + + /** {@inheritDoc} */ + public FieldVector<T> append(T in) { + final T[] out = buildArray(data.length + 1); + System.arraycopy(data, 0, out, 0, data.length); + out[data.length] = in; + return new ArrayFieldVector<T>(out); + } + + /** {@inheritDoc} */ + public FieldVector<T> append(T[] in) { + return new ArrayFieldVector<T>(this, in); + } + + /** {@inheritDoc} */ + public FieldVector<T> getSubVector(int index, int n) { + ArrayFieldVector<T> out = new ArrayFieldVector<T>(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<T> v) { + try { + try { + set(index, (ArrayFieldVector<T>) 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); + } + } + + /** {@inheritDoc} */ + public void setSubVector(int index, T[] v) { + try { + System.arraycopy(v, 0, data, index, v.length); + } catch (IndexOutOfBoundsException e) { + checkIndex(index); + checkIndex(index + v.length - 1); + } + } + + /** + * Set a set of consecutive elements. + * + * @param index index of first element to be set. + * @param v vector containing the values to set. + * @exception MatrixIndexException if the index is + * inconsistent with vector size + */ + public void set(int index, ArrayFieldVector<T> v) + throws MatrixIndexException { + setSubVector(index, v.data); + } + + /** {@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 IllegalArgumentException if the vectors do not + * have the same dimension + */ + protected void checkVectorDimensions(FieldVector<T> v) + throws IllegalArgumentException { + checkVectorDimensions(v.getDimension()); + } + + /** + * Check if instance dimension is equal to some expected value. + * + * @param n expected dimension. + * @exception IllegalArgumentException if the dimension is + * inconsistent with vector size + */ + protected void checkVectorDimensions(int n) + throws IllegalArgumentException { + if (data.length != n) { + throw MathRuntimeException.createIllegalArgumentException( + LocalizedFormats.VECTOR_LENGTH_MISMATCH, + data.length, n); + } + } + + /** + * Test for the equality of two real vectors. + * <p> + * If all coordinates of two real vectors are exactly the same, and none are + * <code>Double.NaN</code>, the two real vectors are considered to be equal. + * </p> + * <p> + * <code>NaN</code> coordinates are considered to affect globally the vector + * and be equals to each other - i.e, if either (or all) coordinates of the + * real vector are equal to <code>Double.NaN</code>, the real vector is equal to + * a vector with all <code>Double.NaN</code> coordinates. + * </p> + * + * @param other Object to test for equality to this + * @return true if two 3D vector objects are equal, false if + * object is null, not an instance of Vector3D, or + * not equal to this Vector3D instance + * + */ + @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<T> rhs = (FieldVector<T>) 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. + * <p>All NaN values have the same hash code.</p> + * @return a hash code value for this object + */ + @Override + public int hashCode() { + int h = 3542; + for (final T a : data) { + h = h ^ a.hashCode(); + } + return h; + } + + /** + * Check if an index is valid. + * @param index index to check + * @exception MatrixIndexException if index is not valid + */ + private void checkIndex(final int index) + throws MatrixIndexException { + if (index < 0 || index >= getDimension()) { + throw new MatrixIndexException(LocalizedFormats.INDEX_OUT_OF_RANGE, + index, 0, getDimension() - 1); + } + } + +} |