Java tutorial
/* * 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 org.apache.commons.math.Field; import org.apache.commons.math.FieldElement; /** * Interface defining a field-valued vector with basic algebraic operations. * <p> * vector element indexing is 0-based -- e.g., <code>getEntry(0)</code> * returns the first element of the vector. * </p> * <p> * The various <code>mapXxx</code> and <code>mapXxxToSelf</code> methods operate * on vectors element-wise, i.e. they perform the same operation (adding a scalar, * applying a function ...) on each element in turn. The <code>mapXxx</code> * versions create a new vector to hold the result and do not change the instance. * The <code>mapXxxToSelf</code> versions use the instance itself to store the * results, so the instance is changed by these methods. In both cases, the result * vector is returned by the methods, this allows to use the <i>fluent API</i> * style, like this: * </p> * <pre> * RealVector result = v.mapAddToSelf(3.0).mapTanToSelf().mapSquareToSelf(); * </pre> * * @param <T> the type of the field elements * @version $Revision: 811786 $ $Date: 2009-09-06 11:36:08 +0200 (dim. 06 sept. 2009) $ * @since 2.0 */ public interface FieldVector<T extends FieldElement<T>> { /** * Get the type of field elements of the vector. * @return type of field elements of the vector */ Field<T> getField(); /** * Returns a (deep) copy of this. * @return vector copy */ FieldVector<T> copy(); /** * 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 */ FieldVector<T> add(FieldVector<T> v) throws IllegalArgumentException; /** * 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 */ FieldVector<T> add(T[] v) throws IllegalArgumentException; /** * Compute this minus v. * @param v vector to be subtracted * @return this + v * @throws IllegalArgumentException if v is not the same size as this */ FieldVector<T> subtract(FieldVector<T> v) throws IllegalArgumentException; /** * Compute this minus v. * @param v vector to be subtracted * @return this + v * @throws IllegalArgumentException if v is not the same size as this */ FieldVector<T> subtract(T[] v) throws IllegalArgumentException; /** * Map an addition operation to each entry. * @param d value to be added to each entry * @return this + d */ FieldVector<T> mapAdd(T d); /** * Map an addition operation to each entry. * <p>The instance <strong>is</strong> changed by this method.</p> * @param d value to be added to each entry * @return for convenience, return this */ FieldVector<T> mapAddToSelf(T d); /** * Map a subtraction operation to each entry. * @param d value to be subtracted to each entry * @return this - d */ FieldVector<T> mapSubtract(T d); /** * Map a subtraction operation to each entry. * <p>The instance <strong>is</strong> changed by this method.</p> * @param d value to be subtracted to each entry * @return for convenience, return this */ FieldVector<T> mapSubtractToSelf(T d); /** * Map a multiplication operation to each entry. * @param d value to multiply all entries by * @return this * d */ FieldVector<T> mapMultiply(T d); /** * Map a multiplication operation to each entry. * <p>The instance <strong>is</strong> changed by this method.</p> * @param d value to multiply all entries by * @return for convenience, return this */ FieldVector<T> mapMultiplyToSelf(T d); /** * Map a division operation to each entry. * @param d value to divide all entries by * @return this / d */ FieldVector<T> mapDivide(T d); /** * Map a division operation to each entry. * <p>The instance <strong>is</strong> changed by this method.</p> * @param d value to divide all entries by * @return for convenience, return this */ FieldVector<T> mapDivideToSelf(T d); /** * Map the 1/x function to each entry. * @return a vector containing the result of applying the function to each entry */ FieldVector<T> mapInv(); /** * Map the 1/x function to each entry. * <p>The instance <strong>is</strong> changed by this method.</p> * @return for convenience, return this */ FieldVector<T> mapInvToSelf(); /** * 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 * @throws IllegalArgumentException if v is not the same size as this */ FieldVector<T> ebeMultiply(FieldVector<T> v) throws IllegalArgumentException; /** * 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 * @throws IllegalArgumentException if v is not the same size as this */ FieldVector<T> ebeMultiply(T[] v) throws IllegalArgumentException; /** * 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 */ FieldVector<T> ebeDivide(FieldVector<T> v) throws IllegalArgumentException; /** * 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 */ FieldVector<T> ebeDivide(T[] v) throws IllegalArgumentException; /** * Returns vector entries as a T array. * @return T array of entries */ T[] getData(); /** * 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 */ T dotProduct(FieldVector<T> v) throws IllegalArgumentException; /** * 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 */ T dotProduct(T[] v) throws IllegalArgumentException; /** 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 */ FieldVector<T> projection(FieldVector<T> v) throws IllegalArgumentException; /** 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 */ FieldVector<T> projection(T[] v) throws IllegalArgumentException; /** * 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 */ FieldMatrix<T> outerProduct(FieldVector<T> v) throws IllegalArgumentException; /** * 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 */ FieldMatrix<T> outerProduct(T[] v) throws IllegalArgumentException; /** * Returns the entry in the specified index. * <p> * The index start at 0 and must be lesser than the size, * otherwise a {@link MatrixIndexException} is thrown. * </p> * @param index index location of entry to be fetched * @return vector entry at index * @throws MatrixIndexException if the index is not valid * @see #setEntry(int, FieldElement) */ T getEntry(int index) throws MatrixIndexException; /** * Set a single element. * @param index element index. * @param value new value for the element. * @exception MatrixIndexException if the index is * inconsistent with vector size * @see #getEntry(int) */ void setEntry(int index, T value) throws MatrixIndexException; /** * Returns the size of the vector. * @return size */ int getDimension(); /** * Construct a vector by appending a vector to this vector. * @param v vector to append to this one. * @return a new vector */ FieldVector<T> append(FieldVector<T> v); /** * Construct a vector by appending a T to this vector. * @param d T to append. * @return a new vector */ FieldVector<T> append(T d); /** * Construct a vector by appending a T array to this vector. * @param a T array to append. * @return a new vector */ FieldVector<T> append(T[] a); /** * Get a subvector from consecutive elements. * @param index index of first element. * @param n number of elements to be retrieved. * @return a vector containing n elements. * @exception MatrixIndexException if the index is * inconsistent with vector size */ FieldVector<T> getSubVector(int index, int n) throws MatrixIndexException; /** * 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 * @see #setSubVector(int, FieldElement[]) */ void setSubVector(int index, FieldVector<T> v) throws MatrixIndexException; /** * 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 * @see #setSubVector(int, FieldVector) */ void setSubVector(int index, T[] v) throws MatrixIndexException; /** * Set all elements to a single value. * @param value single value to set for all elements */ void set(T value); /** * Convert the vector to a T array. * <p>The array is independent from vector data, it's elements * are copied.</p> * @return array containing a copy of vector elements */ T[] toArray(); }