CSRFn
CSRFn is a term occasionally used in sparse linear algebra to denote an operator implemented on a matrix stored in the compressed sparse row (CSR) format. In this usage, CSRFn(A, x) returns the matrix–vector product y = A x, where A is the sparse matrix represented by CSR arrays. The designation can be encountered as either a concrete callable in code or as an abstract operator in theoretical discussions, with variations in exact interpretation across sources.
Definition and representation: A CSR matrix stores three arrays: values of the nonzero entries, column indices
Applications and implementations: CSRFn is commonly used to represent and apply sparse matrices in iterative solvers
Limitations and context: The term CSRFn is not universally standardized and may vary in definition by author
See also: Compressed Sparse Row, sparse matrices, SpMV, iterative methods, linear algebra libraries.