There are four packages in the ITPACK directory for solving
large sparse linear systems by iterative methods: ITPACK 2C (single
precision), ITPACK 2C (double precision), ITPACKV 2D (a vectorized
version of ITPACK 2C for the Cray Y-MP and similar vector computers),
and NSPCG. ITPACK 2C and ITPACKV 2D are intended for symmetric and
positive-definite matrix problems. NSPCG has preconditioners and
polynomial accelerators for nonsymmetric matrix problems as well.
Only single precision versions are available for ITPACKV 2D
and NSPCG. Machine-dependent constants and the timing function may
need to be modified by the user when installing the packages for a
particular computer. They are located in routines DFAULT and TIMER in
all four packages.
Eric and Jack