cern.colt.matrix.tfloat.FloatFactory1D Maven / Gradle / Ivy

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Parallel Colt is a multithreaded version of Colt - a library for high performance scientific computing in Java. It contains efficient algorithms for data analysis, linear algebra, multi-dimensional arrays, Fourier transforms, statistics and histogramming.
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/*
Copyright (C) 1999 CERN - European Organization for Nuclear Research.
Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose 
is hereby granted without fee, provided that the above copyright notice appear in all copies and 
that both that copyright notice and this permission notice appear in supporting documentation. 
CERN makes no representations about the suitability of this software for any purpose. 
It is provided "as is" without expressed or implied warranty.
 */
package cern.colt.matrix.tfloat;

import cern.colt.matrix.tfloat.impl.DenseFloatMatrix1D;
import cern.colt.matrix.tfloat.impl.SparseFloatMatrix1D;
import cern.jet.math.tfloat.FloatFunctions;

/**
 * Factory for convenient construction of 1-d matrices holding float
 * cells. Use idioms like FloatFactory1D.dense.make(1000) to construct
 * dense matrices, FloatFactory1D.sparse.make(1000) to construct sparse
 * matrices.
 * 
 * If the factory is used frequently it might be useful to streamline the
 * notation. For example by aliasing:
 * 
 * 
 * 
 * 
 *  *  FloatFactory1D F = FloatFactory1D.dense;
 *  F.make(1000);
 *  F.descending(10);
 *  F.random(3);
 *  ...
 * 
 * 
 * 
 * 
 * @author [email protected]
 * @version 1.0, 09/24/99
 */
public class FloatFactory1D extends cern.colt.PersistentObject {
    private static final long serialVersionUID = 1L;

    /**
     * A factory producing dense matrices.
     */
    public static final FloatFactory1D dense = new FloatFactory1D();

    /**
     * A factory producing sparse matrices.
     */
    public static final FloatFactory1D sparse = new FloatFactory1D();

    /**
     * Makes this class non instantiable, but still let's others inherit from
     * it.
     */
    protected FloatFactory1D() {
    }

    /**
     * C = A||B; Constructs a new matrix which is the concatenation of two other
     * matrices. Example: 0 1 append 3 4 --> 0 1 3 4.
     */
    public FloatMatrix1D append(FloatMatrix1D A, FloatMatrix1D B) {
        // concatenate
        FloatMatrix1D matrix = make((int) (A.size() + B.size()));
        matrix.viewPart(0, (int) A.size()).assign(A);
        matrix.viewPart((int) A.size(), (int) B.size()).assign(B);
        return matrix;
    }

    /**
     * Constructs a matrix with cells having ascending values. For debugging
     * purposes. Example: 0 1 2
     */
    public FloatMatrix1D ascending(int size) {
        return descending(size).assign(FloatFunctions.chain(FloatFunctions.neg, FloatFunctions.minus(size)));
    }

    /**
     * Constructs a matrix with cells having descending values. For debugging
     * purposes. Example: 2 1 0
     */
    public FloatMatrix1D descending(int size) {
        FloatMatrix1D matrix = make(size);
        int v = 0;
        for (int i = size; --i >= 0;) {
            matrix.setQuick(i, v++);
        }
        return matrix;
    }

    /**
     * Constructs a matrix from the values of the given list. The values are
     * copied. So subsequent changes in values are not reflected in the
     * matrix, and vice-versa.
     * 
     * @param values
     *            The values to be filled into the new matrix.
     * @return a new matrix.
     */
    public FloatMatrix1D make(cern.colt.list.tfloat.AbstractFloatList values) {
        int size = values.size();
        FloatMatrix1D vector = make(size);
        for (int i = size; --i >= 0;)
            vector.set(i, values.get(i));
        return vector;
    }

    /**
     * Constructs a matrix with the given cell values. The values are copied. So
     * subsequent changes in values are not reflected in the matrix,
     * and vice-versa.
     * 
     * @param values
     *            The values to be filled into the new matrix.
     */
    public FloatMatrix1D make(float[] values) {
        if (this == sparse)
            return new SparseFloatMatrix1D(values);
        else
            return new DenseFloatMatrix1D(values);
    }

    /**
     * Constructs a matrix which is the concatenation of all given parts. Cells
     * are copied.
     */
    public FloatMatrix1D make(FloatMatrix1D[] parts) {
        if (parts.length == 0)
            return make(0);

        int size = 0;
        for (int i = 0; i < parts.length; i++)
            size += parts[i].size();

        FloatMatrix1D vector = make(size);
        size = 0;
        for (int i = 0; i < parts.length; i++) {
            vector.viewPart(size, (int) parts[i].size()).assign(parts[i]);
            size += parts[i].size();
        }

        return vector;
    }

    /**
     * Constructs a matrix with the given shape, each cell initialized with
     * zero.
     */
    public FloatMatrix1D make(int size) {
        if (this == sparse)
            return new SparseFloatMatrix1D(size);
        return new DenseFloatMatrix1D(size);
    }

    /**
     * Constructs a matrix with the given shape, each cell initialized with the
     * given value.
     */
    public FloatMatrix1D make(int size, float initialValue) {
        return make(size).assign(initialValue);
    }

    /**
     * Constructs a matrix with uniformly distributed values in (0,1)
     * (exclusive).
     */
    public FloatMatrix1D random(int size) {
        return make(size).assign(cern.jet.math.tfloat.FloatFunctions.random());
    }

    /**
     * C = A||A||..||A; Constructs a new matrix which is concatenated
     * repeat times. Example:
     * 
     *      * 	 0 1
     * 	 repeat(3) -->
     * 	 0 1 0 1 0 1
     * 
     * 
     */
    public FloatMatrix1D repeat(FloatMatrix1D A, int repeat) {
        int size = (int) A.size();
        FloatMatrix1D matrix = make(repeat * size);
        for (int i = repeat; --i >= 0;) {
            matrix.viewPart(size * i, size).assign(A);
        }
        return matrix;
    }

    /**
     * Constructs a randomly sampled matrix with the given shape. Randomly picks
     * exactly Math.round(size*nonZeroFraction) cells and initializes
     * them to value, all the rest will be initialized to zero. Note
     * that this is not the same as setting each cell with probability
     * nonZeroFraction to value.
     * 
     * @throws IllegalArgumentException
     *             if nonZeroFraction < 0 || nonZeroFraction > 1.
     * @see cern.jet.random.tfloat.sampling.FloatRandomSampler
     */
    public FloatMatrix1D sample(int size, float value, float nonZeroFraction) {
        float epsilon = 1e-05f;
        if (nonZeroFraction < 0 - epsilon || nonZeroFraction > 1 + epsilon)
            throw new IllegalArgumentException();
        if (nonZeroFraction < 0)
            nonZeroFraction = 0;
        if (nonZeroFraction > 1)
            nonZeroFraction = 1;

        FloatMatrix1D matrix = make(size);

        int n = Math.round(size * nonZeroFraction);
        if (n == 0)
            return matrix;

        cern.jet.random.tfloat.sampling.FloatRandomSamplingAssistant sampler = new cern.jet.random.tfloat.sampling.FloatRandomSamplingAssistant(
                n, size, new cern.jet.random.tfloat.engine.FloatMersenneTwister());
        for (int i = size; --i >= 0;) {
            if (sampler.sampleNextElement()) {
                matrix.setQuick(i, value);
            }
        }

        return matrix;
    }

    /**
     * Constructs a list from the given matrix. The values are copied. So
     * subsequent changes in values are not reflected in the list, and
     * vice-versa.
     * 
     * @param values
     *            The values to be filled into the new list.
     * @return a new list.
     */
    public cern.colt.list.tfloat.FloatArrayList toList(FloatMatrix1D values) {
        int size = (int) values.size();
        cern.colt.list.tfloat.FloatArrayList list = new cern.colt.list.tfloat.FloatArrayList(size);
        list.setSize(size);
        for (int i = size; --i >= 0;)
            list.setQuick(i, values.get(i));
        return list;
    }
}