void OverwriteCols(DenseMatrix<T>& A,
const DenseMatrix<T>& B,
const std::vector<unsigned int>& col_indices,
const unsigned int num_cols)
{
const unsigned int height = A.Height();
// Overwrite columns of A with B.
if (B.Height() != A.Height())
throw std::logic_error("OverwriteCols: height mismatch");
if (num_cols > static_cast<unsigned int>(A.Width()))
throw std::logic_error("OverwriteCols: col indices out of bounds");
T* buf_a = A.Buffer();
const unsigned int ldim_a = A.LDim();
const T* buf_b = B.LockedBuffer();
const unsigned int ldim_b = B.LDim();
for (unsigned int c=0; c<num_cols; ++c)
{
unsigned int col_a = col_indices[c];
unsigned int offset_a = col_a*ldim_a;
unsigned int offset_b = c*ldim_b;
memcpy(&buf_a[offset_a], &buf_b[offset_b], height * sizeof(T));
}
}
void Overwrite(DenseMatrix<T>& A,
const DenseMatrix<T>& B,
const std::vector<unsigned int>& row_indices,
const std::vector<unsigned int>& col_indices,
const unsigned int num_rows,
const unsigned int num_cols)
{
// Overwrite entries in A with entries in B. The row and column
// index arrays contain the destination indices to be overwritten.
// Matrix B has size num_rows x num_cols.
if (num_rows > static_cast<unsigned int>(A.Height()))
throw std::logic_error("Overwrite: row indices out of bounds");
if (num_cols > static_cast<unsigned int>(A.Width()))
throw std::logic_error("Overwrite: col indices out of bounds");
const T* buf_b = B.LockedBuffer();
const unsigned int ldim_b = B.LDim();
T* buf_a = A.Buffer();
const unsigned int ldim_a = A.LDim();
for (unsigned int c=0; c<num_cols; ++c)
{
unsigned int col_a = col_indices[c];
unsigned int offset_a = ldim_a * col_a;
unsigned int offset_b = ldim_b * c;
for (unsigned int r=0; r<num_rows; ++r)
{
unsigned int row_a = row_indices[r];
//T val = B.Get(r, c);
//A.Set(row_a, col_a, val);
buf_a[offset_a + row_a] = buf_b[offset_b + r];
}
}
}
void ZeroizeSmallValues(DenseMatrix<T>& A, const T tol)
{
// set Aij to zero if |Aij| < tol
T* buf = A.Buffer();
const unsigned int ldim = A.LDim();
const unsigned int height = A.Height();
const unsigned int width = A.Width();
OPENMP_PRAGMA(omp parallel for)
for (unsigned int c=0; c<width; ++c)
{
unsigned int col_offset = c*ldim;
for (unsigned int r=0; r<height; ++r)
{
T val = buf[col_offset + r];
if (std::abs(val) < tol)
{
buf[col_offset + r] = T(0);
}
}
}
}