本文整理汇总了C++中SparseMatrix::ColBuffer方法的典型用法代码示例。如果您正苦于以下问题：C++ SparseMatrix::ColBuffer方法的具体用法？C++ SparseMatrix::ColBuffer怎么用？C++ SparseMatrix::ColBuffer使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类SparseMatrix的用法示例。
在下文中一共展示了SparseMatrix::ColBuffer方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: logic_error
void SparseMatrix<T>::SubMatrixCols(SparseMatrix<T>& result,
const std::vector<unsigned int>& col_indices) const
{
// extract entire columns from the source matrix to form the dest matrix
unsigned int new_width = col_indices.size();
if (0u == new_width)
throw std::logic_error("SparseMatrix: empty column set");
// check the column indices for validty and count nonzeros
unsigned int new_size = 0;
for (auto it=col_indices.begin(); it != col_indices.end(); ++it)
{
// index of next source column
unsigned int c = *it;
if (c >= width_)
throw std::logic_error("SparseMatrix::SubMatrix: column index out of range");
// number of nonzeros in source column c
new_size += (col_offsets_[c+1] - col_offsets_[c]);
}
if (0u == new_size)
throw std::logic_error("SparseMatrix::SubMatrix: submatrix is the zero matrix");
// allocate memory in the result; won't allocate if sufficient memory available
result.Reserve(height_, new_width, new_size);
unsigned int* cols_b = result.ColBuffer();
unsigned int* rows_b = result.RowBuffer();
T* data_b = result.DataBuffer();
unsigned int c_dest = 0;
unsigned int elt_count = 0;
for (auto it=col_indices.begin(); it != col_indices.end(); ++it)
{
// index of the next source column
unsigned int c = *it;
// set element offset for the next dest column
cols_b[c_dest] = elt_count;
unsigned int start = col_offsets_[c];
unsigned int end = col_offsets_[c+1];
for (unsigned int offset = start; offset != end; ++offset)
{
rows_b[elt_count] = row_indices_[offset];
data_b[elt_count] = data_[offset];
++elt_count;
}
// have now completed another column
++c_dest;
}
cols_b[new_width] = elt_count;
assert(new_width == c_dest);
// set the size of the new matrix explicitly, since Load() has been bypassed
result.SetSize(elt_count);
}