/**
* Creates a new matrix by copying the given set of column vectors.
*
* @param columns The column vectors to create a matrix from. Must all be the same dimensionality.
* @return A new matrix whose columns are equal to the given set of columns.
*/
public MatrixType copyColumnVectors(final Collection<? extends Vectorizable> columns) {
// Create the matrix.
final int numRows = VectorUtil.safeGetDimensionality(CollectionUtil.getFirst(columns));
final int numColumns = columns.size();
final MatrixType result = this.createMatrix(numRows, numColumns);
// Fill in the matrix with the columns.
int columnIndex = 0;
for (Vectorizable column : columns) {
result.setColumn(columnIndex, column.convertToVector());
columnIndex++;
}
return result;
}
/**
* Creates a new matrix by copying the given set of row vectors.
*
* @param rows The row vectors to create a matrix from. Must all be the same dimensionality.
* @return A new matrix whose rows are equal to the given set of rows.
*/
public MatrixType copyRowVectors(final Collection<? extends Vectorizable> rows) {
// Create the matrix.
final int numRows = rows.size();
final int numColumns = VectorUtil.safeGetDimensionality(CollectionUtil.getFirst(rows));
final MatrixType result = this.createMatrix(numRows, numColumns);
// Fill in the matrix with the rows.
int rowIndex = 0;
for (Vectorizable row : rows) {
result.setRow(rowIndex, row.convertToVector());
rowIndex++;
}
return result;
}
/**
* Creates a new square matrix whose number of rows and columns match the dimensionality of the
* given vector. It also places the values of the vector on the diagonal of the matrix.
*
* @param diagonal The vector of diagonal values.
* @return A new, square matrix with the diagonal elements equal to the elements of the given
* vector.
*/
public MatrixType createDiagonal(final Vectorizable diagonal) {
final Vector vector = diagonal.convertToVector();
final int dimensionality = vector.getDimensionality();
// Create the matrix.
final MatrixType result = this.createMatrix(dimensionality, dimensionality);
// Set the diagonal values.
for (VectorEntry entry : vector) {
final int i = entry.getIndex();
result.setElement(i, i, entry.getValue());
}
return result;
}
