/**
* Construct from DoubleMatrix2D type
*
* @param aMatrix is a DoubleMatrix2D
*/
public SparseCoordinateFormatMatrix(final DoubleMatrix2D aMatrix) {
Validate.notNull(aMatrix);
// get number of elements
_els = aMatrix.getNumberOfElements();
// tmp arrays, in case we get in a fully populated matrix, intelligent design upstream should
// ensure that this is overkill!
double[] valuesTmp = new double[_els];
int[] xTmp = new int[_els];
int[] yTmp = new int[_els];
// we need unwind the array aMatrix into coordinate form
int localmaxEntriesInARow;
_maxEntriesInARow = -1; // set max entries in a column negative, so that maximiser will work
int ptr = 0;
for (int i = 0; i < aMatrix.getNumberOfRows(); i++) {
localmaxEntriesInARow = 0;
for (int j = 0; j < aMatrix.getNumberOfColumns(); j++) {
if (Double.doubleToLongBits(aMatrix.getEntry(i, j)) != 0L) {
xTmp[ptr] = j;
yTmp[ptr] = i;
valuesTmp[ptr] = aMatrix.getEntry(i, j);
ptr++;
localmaxEntriesInARow++;
}
}
if (localmaxEntriesInARow > _maxEntriesInARow) {
_maxEntriesInARow = localmaxEntriesInARow;
}
}
_values = Arrays.copyOfRange(valuesTmp, 0, ptr);
_x = Arrays.copyOfRange(xTmp, 0, ptr);
_y = Arrays.copyOfRange(yTmp, 0, ptr);
_rows = aMatrix.getNumberOfRows();
_cols = aMatrix.getNumberOfColumns();
}
