Due: April 11 (Thursday)
In homework #2, you have SparseMatrix.java to complete.
Complete SparseMatrix.java.
/*
* DO NOT MODIFY THIS CLASS!
*/
/**
* Represents an entry in a sparse matrix.
* An entry consists of a row index, a column index, and a value.
*/
public class Entry {
/**
* The row index of this entry.
*/
private int row;
/**
* The column index of this entry.
*/
private int col;
/**
* The value of this entry.
*/
private double value;
/**
* Constructs an Entry object with the given row, column, and value.
*
* @param row The row index of this entry.
* @param col The column index of this entry.
* @param value The value of this entry.
*/
public Entry(int row, int col, double value) {
this.row = row;
this.col = col;
this.value = value;
}
/**
* Constructs an Entry object with the same row, column, and value as the given Entry object.
*
* @param other The Entry object to copy.
*/
public Entry(Entry other) {
this.row = other.row;
this.col = other.col;
this.value = other.value;
}
/**
* Compares this Entry object with the specified object for equality.
*
* @param o The object to compare.
* @return true if the specified object is equal to this Entry object; false otherwise.
*/
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof Entry entry)) return false;
return row == entry.row &&
col == entry.col &&
Double.compare(entry.value, value) == 0;
}
/**
* Returns a row index of this entry.
*
* @return The row index of this entry.
*/
public int getRow() {
return row;
}
/**
* Set the row index of this entry.
*
* @param row The row index to set.
*/
public void setRow(int row) {
this.row = row;
}
/**
* Returns a column index of this entry.
*
* @return The column index of this entry.
*/
public int getCol() {
return col;
}
/**
* Set the column index of this entry.
*
* @param col The column index to set.
*/
public void setCol(int col) {
this.col = col;
}
/**
* Returns a value of this entry.
*
* @return The value of this entry.
*/
public double getValue() {
return value;
}
/**
* Set the value of this entry.
*
* @param value The value to set.
*/
public void setValue(double value) {
this.value = value;
}
/**
* Returns a string representation of this entry.
*
* @return A string representation of this entry.
*/
@Override
public String toString() {
return "(" + row + ", " + col + ", " + value + ")";
}
}/**
* Represent an array implementation of a sparse matrix.
* In the context of this assignment, a sparse matrix is represented as an array of Entry objects.
*/
public class ArraySparseMatrix implements SparseMatrix {
/**
* The array of Entry objects.
*/
private Entry[] elements = new Entry[0];
/**
* Constructs an ArraySparseMatrix object with the given capacity.
*
* @param capacity The capacity of the array.
*/
public ArraySparseMatrix(int capacity) {
elements = new Entry[capacity];
/*
* your code goes here if necessary
*/
}
/**
* Create a SparseMatrix object from a two-dimensional array.
* This routine simulates reading from files using two-dimensional matrix.
*
* @param aMatrix The two-dimensional array to be converted to a SparseMatrix object.
* @return a SparseMatrix object created from the given two-dimensional array.
*/
public static SparseMatrix from(double[][] aMatrix) {
/*
* your code goes here
*/
return null;
}
/**
* Transpose the matrix.
*
* @ return a new SparseMatrix object that is the transpose of this matrix
*/
@Override
public SparseMatrix transpose() {
/*
* Your code goes here
*/
return null;
}
/**
* Add aMatrix to this matrix.
*
* @param other SparseMatrix to be added
* @return a new SparseMatrix object that is the sum of this matrix and other matrix
* @throws IllegalArgumentException if the size of the matrix doesn't match
*/
@Override
public SparseMatrix add(SparseMatrix other) {
if (this.getRowCount() != other.getRowCount() || this.getColumnCount() != other.getColumnCount())
throw new IllegalArgumentException("Matrix size doesn't match");
/*
* Your code goes here
*/
return null;
}
/**
* Multiply this matrix with other matrix.
* YOU DON'T HAVE TO IMPLEMENT THIS METHOD.
*
* @param other a SparseMatrix to be multiplied
* @return a new SparseMatrix object that is the product of this matrix and other matrix
* @throws IllegalStateException if dimensions of the matrices are not compatible for multiplication
*/
@Override
public SparseMatrix multiply(SparseMatrix other) {
throw new IllegalStateException("Not implemented");
}
/**
* Get the array of Entry objects.
*
* @return the array of Entry objects
*/
public Entry[] getElements() {
return elements;
}
/**
* Get the number of rows of the matrix.
*
* @return the number of rows of the matrix
*/
@Override
public int getRowCount() {
/*
* Your code goes here
*/
return 0;
}
/**
* Get the number of columns of the matrix.
*
* @return the number of columns of the matrix
*/
@Override
public int getColumnCount() {
/*
* Your code goes here
*/
return 0;
}
/**
* Get the number of non-zero elements in the matrix.
*
* @return the number of non-zero elements in the matrix
*/
@Override
public int getElemCount() {
/*
* Your code goes here
*/
return 0;
}
/**
* Compares this ArraySparseMatrix object with the specified object for equality.
*
* @param obj The object to compare.
* @return true if the specified object is equal to this ArraySparseMatrix object; false otherwise.
*/
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (!(obj instanceof ArraySparseMatrix other)) return false;
if (getRowCount() != other.getRowCount()
|| getColumnCount() != other.getColumnCount()
|| getElemCount() != other.getElemCount())
return false;
for (int i = 0; i < elements.length; i++) {
if (!elements[i].equals(other.elements[i])) return false;
}
return true;
}
/**
* DO NOT MODIFY THIS METHOD!!!
* Returns a string representation of the ArraySparseMatrix object.
*
* @return a string representation of the ArraySparseMatrix object
*/
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
// print meta
builder.append(elements[0].getRow() + "\t" + elements[0].getCol() + "\t" + (int) elements[0].getValue() + "\n");
// print elements
for (int i = 1; i <= getElemCount(); i++)
builder.append(elements[i] + "\n");
return builder.toString();
}
}- You can freely modify the body of each method to complete the code. You can also freely
add
privatefields and methods if necessary. However, no givenpublicmethod signatures should be changed. - You should check the correctness of your program by running test code,
SparseMatricTest.java
- Your source codes archived in
.zipor.jarformat.- Subject: Homework#1, Section [A|B], 성명, 학번
- Email to your TA (김정인, rkrkrk24@hanyang.ac.kr)