// sucks, but so does the visitor pattern. not often used.
public void plusEquals(ConstantMatrix m, double factor) {
if (m instanceof SparseVector) {
values.plusEqualsSparse((SparseVector) m, factor);
} else if (m instanceof SparseMatrixn) {
SparseMatrixn smn = (SparseMatrixn) m;
if (Arrays.equals(sizes, smn.sizes)) {
values.plusEqualsSparse(smn.values, factor);
} else {
throw new UnsupportedOperationException("sizes of " + m + " do not match " + this);
}
} else {
throw new UnsupportedOperationException("Can't add " + m + " to " + this);
}
}
