inline
void ColumnView(sparse_matrix_t<T>& A, sparse_matrix_t<T>& B, int j, int width) {
const int *bindptr = B.indptr();
const int *bindices = B.indices();
double *bvalues = B.values();
int start = bindptr[j];
int *indptr = new int[width + 1];
for (int i = 0; i <= width; i++)
indptr[i] = bindptr[j + i] - start;
const int *indices = bindices + start;
double *values = bvalues + start;
A.attach(indptr, indices, values, indptr[width], A.height(), width,
true, false, false);
}
inline void Gemv(El::Orientation oA,
T alpha, const sparse_matrix_t<T>& A, const El::Matrix<T>& x,
T beta, El::Matrix<T>& y) {
// TODO verify sizes etc.
const int* indptr = A.indptr();
const int* indices = A.indices();
const double *values = A.locked_values();
double *yd = y.Buffer();
const double *xd = x.LockedBuffer();
int n = A.width();
if (oA == El::NORMAL) {
El::Scale(beta, y);
# if SKYLARK_HAVE_OPENMP
# pragma omp parallel for
# endif
for(int col = 0; col < n; col++) {
T xv = alpha * xd[col];
for (int j = indptr[col]; j < indptr[col + 1]; j++) {
int row = indices[j];
T val = values[j];
yd[row] += val * xv;
}
}
} else {
# if SKYLARK_HAVE_OPENMP
# pragma omp parallel for
# endif
for(int col = 0; col < n; col++) {
double yv = beta * yd[col];
for (int j = indptr[col]; j < indptr[col + 1]; j++) {
int row = indices[j];
T val = values[j];
yv += alpha * val * xd[row];
}
yd[col] = yv;
}
}
}