structure

A type representing the sparsity structure of a sparse complex matrix.

Declaration

var structure: SparseMatrixStructureComplex

Discussion

The sparsity structure is represented in block compressed sparse column (block CSC) format. The matrix is divided into a regular grid of rowCount x columnCount blocks each of size blockSize x blockSize, and only blocks containing a non-zero entry are stored. CSC format is used to store the locations of these blocks. For each block column, a list of block row indices for non-zero blocks are stored, and the lists for each column are stored contiguously one after the other. Hence the row indices for column j are given by rowIndices[columnStarts[j]:columnStarts[j+1]], where columnStarts[] is storing the location of the first index in each column.

If the blockSize is 1, then this format is exactly equivalent to standard CSC format.

CSR format data can be simulated by using a blockSize of 1 and setting the transpose attribute (strictly this is still a transposed CSC matrix, so rowCount and columnCount will be transposed compared to true CSR).

rowCount: Number of (block) rows in matrix.
columnCount: Number of (block) columns in matrix.
columnStarts: Specifies where each (block) column starts in rowIndices array.
rowIndices: Specifies the (block) row indices of the matrix.
attributes: The attribute meta-data for the matrix, for example whether the matrix is symmetric (Hermitian) and only half the entries are stored.
blockSize: The block size of the matrix.