F11XSF computes a matrix-vector product involving a complex sparse Hermitian matrix stored in symmetric coordinate storage format.
F11XSF computes the matrix-vector product
where
A is an
n by
n complex Hermitian sparse matrix, of arbitrary sparsity pattern, stored in symmetric coordinate storage (SCS) format (see
Section 2.1.2 in the F11 Chapter Introduction). The array
A stores all the nonzero elements in the lower triangular part of
A, while arrays
IROW and
ICOL store the corresponding row and column indices respectively.
None.
If on entry
IFAIL=0 or
-1, explanatory error messages are output on the current error message unit (as defined by
X04AAF).
The computed vector
y satisfies the error bound
where
cn is a modest linear function of
n, and
ε is the
machine precision.
The time taken for a call to F11XSF is proportional to
NNZ.