Added Matrix-valued row, column, and subMatrix accessors as suggested
by Kim van der Linde (Pr #30897). Implemented equals and hashcode. Modified toString() to handle empty matrix. git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/math/trunk@141481 13f79535-47bb-0310-9956-ffa450edef68
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Phil Steitz
parent
691be295d1
commit
3cc04c99f0
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@ -25,7 +25,7 @@ import java.math.BigDecimal;
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* Matrix element indexing is 0-based -- e.g., <code>getEntry(0, 0)</code>
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* returns the element in the first row, first column of the matrix.
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*
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* @version $Revision: 1.7 $ $Date: 2004/09/05 01:19:23 $
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* @version $Revision: 1.8 $ $Date: 2004/10/25 02:21:20 $
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*/
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public interface BigMatrix {
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@ -151,6 +151,54 @@ public interface BigMatrix {
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*/
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BigDecimal getNorm();
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/**
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* Gets a submatrix. Rows and columns are indicated
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* counting from 0 to n-1.
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*
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* @param startRow Initial row index
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* @param endRow Final row index
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* @param startColumn Initial column index
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* @param endColumn Final column index
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* @return The subMatrix containing the data of the
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* specified rows and columns
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* @exception MatrixIndexException if the indices are not valid
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*/
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BigMatrix getSubMatrix(int startRow, int endRow, int startColumn,
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int endColumn) throws MatrixIndexException;
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/**
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* Gets a submatrix. Rows and columns are indicated
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* counting from 0 to n-1.
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*
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* @param selectedRows Array of row indices.
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* @param selectedColumns Array of column indices.
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* @return The subMatrix containing the data in the
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* specified rows and columns
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* @exception MatrixIndexException if row or column selections are not valid
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*/
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BigMatrix getSubMatrix(int[] selectedRows, int[] selectedColumns)
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throws MatrixIndexException;
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/**
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* Returns the entries in row number <code>row</code>
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* as a row matrix. Row indices start at 0.
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*
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* @param row the row to be fetched
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* @return row matrix
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* @throws MatrixIndexException if the specified row index is invalid
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*/
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BigMatrix getRowMatrix(int row) throws MatrixIndexException;
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/**
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* Returns the entries in column number <code>column</code>
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* as a column matrix. Column indices start at 0.
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*
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* @param column the column to be fetched
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* @return column matrix
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* @throws MatrixIndexException if the specified column index is invalid
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*/
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BigMatrix getColumnMatrix(int column) throws MatrixIndexException;
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/**
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* Returns the entries in row number <code>row</code> as an array.
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* <p>
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@ -43,7 +43,7 @@ import java.math.BigDecimal;
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* As specified in the {@link BigMatrix} interface, matrix element indexing
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* is 0-based -- e.g., <code>getEntry(0, 0)</code>
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* returns the element in the first row, first column of the matrix.</li></ul>
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* @version $Revision: 1.6 $ $Date: 2004/09/05 01:19:23 $
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* @version $Revision: 1.7 $ $Date: 2004/10/25 02:21:20 $
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*/
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public class BigMatrixImpl implements BigMatrix, Serializable {
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@ -429,6 +429,108 @@ public class BigMatrixImpl implements BigMatrix, Serializable {
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return maxColSum;
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}
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/**
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* Gets a submatrix. Rows and columns are indicated
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* counting from 0 to n-1.
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*
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* @param startRow Initial row index
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* @param endRow Final row index
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* @param startColumn Initial column index
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* @param endColumn Final column index
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* @return The subMatrix containing the data of the
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* specified rows and columns
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* @exception MatrixIndexException if row or column selections are not valid
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*/
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public BigMatrix getSubMatrix(int startRow, int endRow, int startColumn,
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int endColumn) throws MatrixIndexException {
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if (startRow < 0 || startRow > endRow || endRow > data.length ||
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startColumn < 0 || startColumn > endColumn ||
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endColumn > data[0].length ) {
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throw new MatrixIndexException(
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"invalid row or column index selection");
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}
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BigMatrixImpl subMatrix = new BigMatrixImpl(endRow - startRow+1,
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endColumn - startColumn+1);
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BigDecimal[][] subMatrixData = subMatrix.getDataRef();
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for (int i = startRow; i <= endRow; i++) {
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for (int j = startColumn; j <= endColumn; j++) {
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subMatrixData[i - startRow][j - startColumn] = data[i][j];
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}
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}
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return subMatrix;
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}
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/**
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* Gets a submatrix. Rows and columns are indicated
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* counting from 0 to n-1.
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*
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* @param selectedRows Array of row indices must be non-empty
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* @param selectedColumns Array of column indices must be non-empty
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* @return The subMatrix containing the data in the
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* specified rows and columns
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* @exception MatrixIndexException if supplied row or column index arrays
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* are not valid
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*/
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public BigMatrix getSubMatrix(int[] selectedRows, int[] selectedColumns)
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throws MatrixIndexException {
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if (selectedRows.length * selectedColumns.length == 0) {
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throw new MatrixIndexException(
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"selected row and column index arrays must be non-empty");
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}
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BigMatrixImpl subMatrix = new BigMatrixImpl(selectedRows.length,
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selectedColumns.length);
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BigDecimal[][] subMatrixData = subMatrix.getDataRef();
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try {
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for (int i = 0; i < selectedRows.length; i++) {
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for (int j = 0; j < selectedColumns.length; j++) {
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subMatrixData[i][j] = data[selectedRows[i]][selectedColumns[j]];
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}
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}
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}
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catch (ArrayIndexOutOfBoundsException e) {
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throw new MatrixIndexException("matrix dimension mismatch");
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}
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return subMatrix;
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}
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/**
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* Returns the entries in row number <code>row</code>
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* as a row matrix. Row indices start at 0.
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*
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* @param row the row to be fetched
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* @return row matrix
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* @throws MatrixIndexException if the specified row index is invalid
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*/
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public BigMatrix getRowMatrix(int row) throws MatrixIndexException {
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if ( !isValidCoordinate( row, 0)) {
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throw new MatrixIndexException("illegal row argument");
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}
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int ncols = this.getColumnDimension();
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BigDecimal[][] out = new BigDecimal[1][ncols];
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System.arraycopy(data[row], 0, out[0], 0, ncols);
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return new BigMatrixImpl(out);
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}
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/**
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* Returns the entries in column number <code>column</code>
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* as a column matrix. Column indices start at 0.
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*
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* @param column the column to be fetched
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* @return column matrix
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* @throws MatrixIndexException if the specified column index is invalid
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*/
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public BigMatrix getColumnMatrix(int column) throws MatrixIndexException {
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if ( !isValidCoordinate( 0, column)) {
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throw new MatrixIndexException("illegal column argument");
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}
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int nRows = this.getRowDimension();
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BigDecimal[][] out = new BigDecimal[nRows][1];
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for (int row = 0; row < nRows; row++) {
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out[row][0] = data[row][column];
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}
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return new BigMatrixImpl(out);
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}
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/**
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* Returns the entries in row number <code>row</code> as an array.
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* <p>
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@ -1005,20 +1107,74 @@ public class BigMatrixImpl implements BigMatrix, Serializable {
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public String toString() {
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StringBuffer res = new StringBuffer();
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res.append("BigMatrixImpl{");
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for (int i = 0; i < data.length; i++) {
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if (i > 0)
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res.append(",");
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res.append("{");
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for (int j = 0; j < data[0].length; j++) {
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if (j > 0)
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if (data != null) {
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for (int i = 0; i < data.length; i++) {
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if (i > 0)
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res.append(",");
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res.append(data[i][j]);
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} //for
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res.append("}");
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} //for
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res.append("{");
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for (int j = 0; j < data[0].length; j++) {
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if (j > 0)
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res.append(",");
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res.append(data[i][j]);
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}
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res.append("}");
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}
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}
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res.append("}");
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return res.toString();
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} //toString
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}
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/**
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* Returns true iff <code>object</code> is a
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* <code>BigMatrixImpl</code> instance with the same dimensions as this
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* and all corresponding matrix entries are equal. BigDecimal.equals
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* is used to compare corresponding entries.
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*
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* @param object the object to test equality against.
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* @return true if object equals this
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*/
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public boolean equals(Object object) {
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if (object == this ) {
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return true;
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}
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if (object instanceof BigMatrixImpl == false) {
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return false;
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}
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BigMatrix m = (BigMatrix) object;
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int nRows = getRowDimension();
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int nCols = getColumnDimension();
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if (m.getColumnDimension() != nCols || m.getRowDimension() != nRows) {
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return false;
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}
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for (int row = 0; row < nRows; row++) {
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for (int col = 0; col < nCols; col++) {
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if (!data[row][col].equals(m.getEntry(row, col))) {
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return false;
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}
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}
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}
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return true;
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}
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/**
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* Computes a hashcode for the matrix.
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*
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* @return hashcode for matrix
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*/
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public int hashCode() {
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int ret = 7;
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int nRows = getRowDimension();
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int nCols = getColumnDimension();
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ret = ret * 31 + nRows;
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ret = ret * 31 + nCols;
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for (int row = 0; row < nRows; row++) {
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for (int col = 0; col < nCols; col++) {
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ret = ret * 31 + (11 * (row+1) + 17 * (col+1)) *
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data[row][col].hashCode();
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}
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}
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return ret;
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}
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//------------------------ Protected methods
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