3. Design Goals and Implementation Details

Several successful iterative solver packages have been developed over the years, most notably NSPCG [2,1]. However, no package had the desired combination of:

1.

the latest methods, as well as a reasonable framework for adding new methods,

2.

reasonable support for various coefficient storage formats, as well as a framework for adding new storage formats, and support for user-defined storage (including matrix-free operation),

3.

reasonable support for custom preconditioning,

4.

speed,

5.

portability, and

6.

robustness.

JTPACK77 strives to meet these needs.