Java tutorial
/* * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ /* * BinarySparseInstance.java * Copyright (C) 2002-2012 University of Waikato, Hamilton, New Zealand * */ package weka.core; import java.util.ArrayList; import java.util.Enumeration; /** * Class for storing a binary-data-only instance as a sparse vector. A sparse * instance only requires storage for those attribute values that are non-zero. * Since the objective is to reduce storage requirements for datasets with large * numbers of default values, this also includes nominal attributes -- the first * nominal value (i.e. that which has index 0) will not require explicit * storage, so rearrange your nominal attribute value orderings if necessary. * Missing values are not supported, and will be treated as 1 (true). * * @version $Revision$ */ public class BinarySparseInstance extends SparseInstance { /** for serialization */ private static final long serialVersionUID = -5297388762342528737L; /** * Constructor that generates a sparse instance from the given instance. * Reference to the dataset is set to null. (ie. the instance doesn't have * access to information about the attribute types) * * @param instance the instance from which the attribute values and the weight * are to be copied */ public BinarySparseInstance(Instance instance) { m_Weight = instance.weight(); m_Dataset = null; m_NumAttributes = instance.numAttributes(); if (instance instanceof SparseInstance) { m_AttValues = null; m_Indices = ((SparseInstance) instance).m_Indices; } else { int[] tempIndices = new int[instance.numAttributes()]; int vals = 0; for (int i = 0; i < instance.numAttributes(); i++) { if (instance.value(i) != 0) { tempIndices[vals] = i; vals++; } } m_AttValues = null; m_Indices = new int[vals]; System.arraycopy(tempIndices, 0, m_Indices, 0, vals); } } /** * Constructor that copies the info from the given instance. Reference to the * dataset is set to null. (ie. the instance doesn't have access to * information about the attribute types) * * @param instance the instance from which the attribute info is to be copied */ public BinarySparseInstance(SparseInstance instance) { m_AttValues = null; m_Indices = instance.m_Indices; m_Weight = instance.m_Weight; m_NumAttributes = instance.m_NumAttributes; m_Dataset = null; } /** * Constructor that generates a sparse instance from the given parameters. * Reference to the dataset is set to null. (ie. the instance doesn't have * access to information about the attribute types) * * @param weight the instance's weight * @param attValues a vector of attribute values */ public BinarySparseInstance(double weight, double[] attValues) { m_Weight = weight; m_Dataset = null; m_NumAttributes = attValues.length; int[] tempIndices = new int[m_NumAttributes]; int vals = 0; for (int i = 0; i < m_NumAttributes; i++) { if (attValues[i] != 0) { tempIndices[vals] = i; vals++; } } m_AttValues = null; m_Indices = new int[vals]; System.arraycopy(tempIndices, 0, m_Indices, 0, vals); } /** * Constructor that inititalizes instance variable with given values. * Reference to the dataset is set to null. (ie. the instance doesn't have * access to information about the attribute types) * * @param weight the instance's weight * @param indices the indices of the given values in the full vector * @param maxNumValues the maximium number of values that can be stored */ public BinarySparseInstance(double weight, int[] indices, int maxNumValues) { m_AttValues = null; m_Indices = indices; m_Weight = weight; m_NumAttributes = maxNumValues; m_Dataset = null; } /** * Constructor of an instance that sets weight to one, all values to 1, and * the reference to the dataset to null. (ie. the instance doesn't have access * to information about the attribute types) * * @param numAttributes the size of the instance */ public BinarySparseInstance(int numAttributes) { m_AttValues = null; m_NumAttributes = numAttributes; m_Indices = new int[numAttributes]; for (int i = 0; i < m_Indices.length; i++) { m_Indices[i] = i; } m_Weight = 1; m_Dataset = null; } /** * Produces a shallow copy of this instance. The copy has access to the same * dataset. (if you want to make a copy that doesn't have access to the * dataset, use <code>new BinarySparseInstance(instance)</code> * * @return the shallow copy */ @Override public Object copy() { BinarySparseInstance result = new BinarySparseInstance(this); result.m_Dataset = m_Dataset; return result; } /** * Copies the instance but fills up its values based on the given array * of doubles. The copy has access to the same dataset. * * @param values the array with new values * @return the new instance */ public Instance copy(double[] values) { BinarySparseInstance result = new BinarySparseInstance(this.m_Weight, values); result.m_Dataset = m_Dataset; return result; } /** * Merges this instance with the given instance and returns the result. * Dataset is set to null. * * @param inst the instance to be merged with this one * @return the merged instances */ @Override public Instance mergeInstance(Instance inst) { int[] indices = new int[numValues() + inst.numValues()]; int m = 0; for (int j = 0; j < numValues(); j++) { indices[m++] = index(j); } for (int j = 0; j < inst.numValues(); j++) { if (inst.valueSparse(j) != 0) { indices[m++] = numAttributes() + inst.index(j); } } if (m != indices.length) { // Need to truncate int[] newInd = new int[m]; System.arraycopy(indices, 0, newInd, 0, m); indices = newInd; } return new BinarySparseInstance(1.0, indices, numAttributes() + inst.numAttributes()); } /** * Does nothing, since we don't support missing values. * * @param array containing the means and modes */ @Override public void replaceMissingValues(double[] array) { // Does nothing, since we don't store missing values. } /** * Sets a specific value in the instance to the given value (internal * floating-point format). Performs a deep copy of the vector of attribute * values before the value is set. * * @param attIndex the attribute's index * @param value the new attribute value (If the corresponding attribute is * nominal (or a string) then this is the new value's index as a * double). */ @Override public void setValue(int attIndex, double value) { int index = locateIndex(attIndex); if ((index >= 0) && (m_Indices[index] == attIndex)) { if (value == 0) { int[] tempIndices = new int[m_Indices.length - 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, index); System.arraycopy(m_Indices, index + 1, tempIndices, index, m_Indices.length - index - 1); m_Indices = tempIndices; } } else { if (value != 0) { int[] tempIndices = new int[m_Indices.length + 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1); tempIndices[index + 1] = attIndex; System.arraycopy(m_Indices, index + 1, tempIndices, index + 2, m_Indices.length - index - 1); m_Indices = tempIndices; } } } /** * Sets a specific value in the instance to the given value (internal * floating-point format). Performs a deep copy of the vector of attribute * values before the value is set. * * @param indexOfIndex the index of the attribute's index * @param value the new attribute value (If the corresponding attribute is * nominal (or a string) then this is the new value's index as a * double). */ @Override public void setValueSparse(int indexOfIndex, double value) { if (value == 0) { int[] tempIndices = new int[m_Indices.length - 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, indexOfIndex); System.arraycopy(m_Indices, indexOfIndex + 1, tempIndices, indexOfIndex, m_Indices.length - indexOfIndex - 1); m_Indices = tempIndices; } } /** * Returns the values of each attribute as an array of doubles. * * @return an array containing all the instance attribute values */ @Override public double[] toDoubleArray() { double[] newValues = new double[m_NumAttributes]; for (int i = 0; i < m_Indices.length; i++) { newValues[m_Indices[i]] = 1.0; } return newValues; } /** * Returns the description of one instance in sparse format. If the instance * doesn't have access to a dataset, it returns the internal floating-point * values. Quotes string values that contain whitespace characters. * * @return the instance's description as a string */ @Override public String toString() { StringBuffer text = new StringBuffer(); text.append('{'); for (int i = 0; i < m_Indices.length; i++) { if (i > 0) { text.append(","); } if (m_Dataset == null) { text.append(m_Indices[i] + " 1"); } else { if (m_Dataset.attribute(m_Indices[i]).isNominal() || m_Dataset.attribute(m_Indices[i]).isString()) { text.append(m_Indices[i] + " " + Utils.quote(m_Dataset.attribute(m_Indices[i]).value(1))); } else { text.append(m_Indices[i] + " 1"); } } } text.append('}'); if (m_Weight != 1.0) { text.append(",{" + Utils.doubleToString(m_Weight, AbstractInstance.s_numericAfterDecimalPoint) + "}"); } return text.toString(); } /** * Returns an instance's attribute value in internal format. * * @param attIndex the attribute's index * @return the specified value as a double (If the corresponding attribute is * nominal (or a string) then it returns the value's index as a * double). */ @Override public double value(int attIndex) { int index = locateIndex(attIndex); if ((index >= 0) && (m_Indices[index] == attIndex)) { return 1.0; } else { return 0.0; } } /** * Returns an instance's attribute value in internal format. Does exactly the * same thing as value() if applied to an Instance. * * @param indexOfIndex the index of the attribute's index * @return the specified value as a double (If the corresponding attribute is * nominal (or a string) then it returns the value's index as a * double). */ @Override public final double valueSparse(int indexOfIndex) { return 1; } /** * Deletes an attribute at the given position (0 to numAttributes() - 1). * * @param position the attribute's position */ @Override protected void forceDeleteAttributeAt(int position) { int index = locateIndex(position); m_NumAttributes--; if ((index >= 0) && (m_Indices[index] == position)) { int[] tempIndices = new int[m_Indices.length - 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, index); for (int i = index; i < m_Indices.length - 1; i++) { tempIndices[i] = m_Indices[i + 1] - 1; } m_Indices = tempIndices; } else { int[] tempIndices = new int[m_Indices.length]; System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1); for (int i = index + 1; i < m_Indices.length - 1; i++) { tempIndices[i] = m_Indices[i] - 1; } m_Indices = tempIndices; } } /** * Inserts an attribute at the given position (0 to numAttributes()) and sets * its value to 1. * * @param position the attribute's position */ @Override protected void forceInsertAttributeAt(int position) { int index = locateIndex(position); m_NumAttributes++; if ((index >= 0) && (m_Indices[index] == position)) { int[] tempIndices = new int[m_Indices.length + 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, index); tempIndices[index] = position; for (int i = index; i < m_Indices.length; i++) { tempIndices[i + 1] = m_Indices[i] + 1; } m_Indices = tempIndices; } else { int[] tempIndices = new int[m_Indices.length + 1]; System.arraycopy(m_Indices, 0, tempIndices, 0, index + 1); tempIndices[index + 1] = position; for (int i = index + 1; i < m_Indices.length; i++) { tempIndices[i + 1] = m_Indices[i] + 1; } m_Indices = tempIndices; } } /** * Main method for testing this class. * * @param options the command line options - ignored */ public static void main(String[] options) { try { // Create numeric attributes "length" and "weight" Attribute length = new Attribute("length"); Attribute weight = new Attribute("weight"); // Create vector to hold nominal values "first", "second", "third" ArrayList<String> my_nominal_values = new ArrayList<String>(3); my_nominal_values.add("first"); my_nominal_values.add("second"); // Create nominal attribute "position" Attribute position = new Attribute("position", my_nominal_values); // Create vector of the above attributes ArrayList<Attribute> attributes = new ArrayList<Attribute>(3); attributes.add(length); attributes.add(weight); attributes.add(position); // Create the empty dataset "race" with above attributes Instances race = new Instances("race", attributes, 0); // Make position the class attribute race.setClassIndex(position.index()); // Create empty instance with three attribute values BinarySparseInstance inst = new BinarySparseInstance(3); // Set instance's values for the attributes "length", "weight", and // "position" inst.setValue(length, 5.3); inst.setValue(weight, 300); inst.setValue(position, "first"); // Set instance's dataset to be the dataset "race" inst.setDataset(race); // Print the instance System.out.println("The instance: " + inst); // Print the first attribute System.out.println("First attribute: " + inst.attribute(0)); // Print the class attribute System.out.println("Class attribute: " + inst.classAttribute()); // Print the class index System.out.println("Class index: " + inst.classIndex()); // Say if class is missing System.out.println("Class is missing: " + inst.classIsMissing()); // Print the instance's class value in internal format System.out.println("Class value (internal format): " + inst.classValue()); // Print a shallow copy of this instance SparseInstance copy = (SparseInstance) inst.copy(); System.out.println("Shallow copy: " + copy); // Set dataset for shallow copy copy.setDataset(inst.dataset()); System.out.println("Shallow copy with dataset set: " + copy); // Print out all values in internal format System.out.print("All stored values in internal format: "); for (int i = 0; i < inst.numValues(); i++) { if (i > 0) { System.out.print(","); } System.out.print(inst.valueSparse(i)); } System.out.println(); // Set all values to zero System.out.print("All values set to zero: "); while (inst.numValues() > 0) { inst.setValueSparse(0, 0); } for (int i = 0; i < inst.numValues(); i++) { if (i > 0) { System.out.print(","); } System.out.print(inst.valueSparse(i)); } System.out.println(); // Set all values to one System.out.print("All values set to one: "); for (int i = 0; i < inst.numAttributes(); i++) { inst.setValue(i, 1); } for (int i = 0; i < inst.numValues(); i++) { if (i > 0) { System.out.print(","); } System.out.print(inst.valueSparse(i)); } System.out.println(); // Unset dataset for copy, delete first attribute, and insert it again copy.setDataset(null); copy.deleteAttributeAt(0); copy.insertAttributeAt(0); copy.setDataset(inst.dataset()); System.out.println("Copy with first attribute deleted and inserted: " + copy); // Same for second attribute copy.setDataset(null); copy.deleteAttributeAt(1); copy.insertAttributeAt(1); copy.setDataset(inst.dataset()); System.out.println("Copy with second attribute deleted and inserted: " + copy); // Same for last attribute copy.setDataset(null); copy.deleteAttributeAt(2); copy.insertAttributeAt(2); copy.setDataset(inst.dataset()); System.out.println("Copy with third attribute deleted and inserted: " + copy); // Enumerate attributes (leaving out the class attribute) System.out.println("Enumerating attributes (leaving out class):"); Enumeration<Attribute> enu = inst.enumerateAttributes(); while (enu.hasMoreElements()) { Attribute att = enu.nextElement(); System.out.println(att); } // Headers are equivalent? System.out.println("Header of original and copy equivalent: " + inst.equalHeaders(copy)); // Test for missing values System.out.println("Length of copy missing: " + copy.isMissing(length)); System.out.println("Weight of copy missing: " + copy.isMissing(weight.index())); System.out.println("Length of copy missing: " + Utils.isMissingValue(copy.value(length))); // Prints number of attributes and classes System.out.println("Number of attributes: " + copy.numAttributes()); System.out.println("Number of classes: " + copy.numClasses()); // Replace missing values double[] meansAndModes = { 2, 3, 0 }; copy.replaceMissingValues(meansAndModes); System.out.println("Copy with missing value replaced: " + copy); // Setting and getting values and weights copy.setClassMissing(); System.out.println("Copy with missing class: " + copy); copy.setClassValue(0); System.out.println("Copy with class value set to first value: " + copy); copy.setClassValue("second"); System.out.println("Copy with class value set to \"second\": " + copy); copy.setMissing(1); System.out.println("Copy with second attribute set to be missing: " + copy); copy.setMissing(length); System.out.println("Copy with length set to be missing: " + copy); copy.setValue(0, 0); System.out.println("Copy with first attribute set to 0: " + copy); copy.setValue(weight, 1); System.out.println("Copy with weight attribute set to 1: " + copy); copy.setValue(position, "second"); System.out.println("Copy with position set to \"second\": " + copy); copy.setValue(2, "first"); System.out.println("Copy with last attribute set to \"first\": " + copy); System.out.println("Current weight of instance copy: " + copy.weight()); copy.setWeight(2); System.out.println("Current weight of instance copy (set to 2): " + copy.weight()); System.out.println("Last value of copy: " + copy.toString(2)); System.out.println("Value of position for copy: " + copy.toString(position)); System.out.println("Last value of copy (internal format): " + copy.value(2)); System.out.println("Value of position for copy (internal format): " + copy.value(position)); } catch (Exception e) { e.printStackTrace(); } } /** * Returns the revision string. * * @return the revision */ @Override public String getRevision() { return RevisionUtils.extract("$Revision$"); } }