Hi Phil,
As I do not have any CVS set up, so I do it this way:
4) Add the following new methods to both RealMatrix and BigMatrix
interfaces:
RealMatrix getSubMatrix (int startRow, int endRow, int startColumn,
int endColumn)
RealMatrix getSubMatrix (int[] rows, int[] columns)
RealMatrix getRowMatrix(int row)
RealMatrix getColumnMatrix(int row)
RealMatrix createRowMatrix(double[] row)
RealMatrix createColumnMatrix(double[] column)
/**
* Get a submatrix. Rows and columns are indicated
* counting from 0 to n-1.
*
* @param startRow Initial row index
* @param endRow Final row index
* @param startColumn Initial column index
* @param endColumn Final column index
* @return The subMatrix containing the data of the
* specified rows and columns
* @exception MatrixIndexException matrix dimension
* mismatch
*/
public RealMatrix getSubMatrix(int startRow, int endRow, int startColumn,
int endColumn) throws MatrixIndexException
{
RealMatrix subMatrix = new RealMatrix(endRow - startRow + 1,
endColumn - startColumn + 1);
double[][] subMatrixData = subMatrix.getDataRef();
try
{
for (int i = startRow; i <= endRow; i++)
{
for (int j = startColumn; j <= endColumn; j++)
{
subMatrixData[i - startRow][j - startColumn] = data[i][j];
}
}
}
catch (ArrayIndexOutOfBoundsException e)
{
throw new MatrixIndexException("matrix dimension mismatch");
}
return subMatrix;
}
/**
* Get a submatrix. Rows and columns are indicated
* counting from 0 to n-1.
*
* @param rows Array of row indices.
* @param columns Array of column indices.
* @return The subMatrix containing the data of the
* specified rows and columns
* @exception MatrixIndexException matrix dimension
* mismatch
*/
public RealMatrix getSubMatrix(int[] selectedRows, int[] selectedColumns)
throws MatrixIndexException
{
RealMatrix subMatrix = new RealMatrix(selectedRows.length,
selectedColumns.length);
double[][] subMatrixData = subMatrix.getDataRef();
try
{
for (int i = 0; i < selectedRows.length; i++)
{
for (int j = 0; j < selectedColumns.length; j++)
{
subMatrixData[i][j] = data[selectedRows[i]][selectedColumns[j]];
}
}
}
catch (ArrayIndexOutOfBoundsException e)
{
throw new MatrixIndexException("matrix dimension mismatch");
}
return subMatrix;
}
/**
* Returns the entries in row number <code>row</code>
* as a Matrix object.
*
* @param row the row to be fetched
* @return RealMatrix with only one row
* @throws MatrixIndexException if the specified row is
* greater than the number of rows in this
* matrix
*/
public Matrix getRowMatrix(int row) throws MatrixIndexException
{
if (!isValidCoordinate(row, 0)) { throw new MatrixIndexException(
"illegal row argument"); }
double[][] out = new double[1][columns];
for (int y = 0; y < columns; y++)
{
out[0][y] = data[row][y];
}
return new RealMatrix (out);
}
/**
* Returns the entries in column number <code>col</code>
* as a RealMatrix object.
*
* @param col column to fetch
* @return RealMatrix with only one column
* @throws MatrixIndexException if the specified column
* is greater than the number of columns in
* this matrix
*/
public RealMatrix getColumnMatrix(int col) throws MatrixIndexException
{
if (!isValidCoordinate(0, col)) { throw new MatrixIndexException(
"illegal row argument"); }
double[][] out = new double[rows][1];
for (int y = 0; y < rows; y++)
{
out[y][0] = data[y][col];
}
return new RealMatrix (out);
}
I do not have ready to use code for the last two methods.
I might have missed to add some 'Real's before the Matrix names....
Cheers,
Kim
--
http://www.kimvdlinde.com
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