Choices for Preconditioner

The naming convention used for $\langle$ precon $\rangle$, the routine specifying the preconditioner, indicates both the preconditioner and the data storage format. $\langle$ precon $\rangle$must be declared EXTERNAL in the user's calling program and has the form $\langle$ name $\rangle i$ where

i = 1	for primary storage format
= 2	for symmetric diagonal storage
= 3	for nonsymmetric diagonal storage
= 4	for symmetric coordinate storage
= 5	for nonsymmetric coordinate storage
= 6	for permuted primary storage format
= 7	for permuted diagonal storage (symmetric or nonsymmetric)

(See Section 8 for a detailed description of these storage schemes.)

If i = 1,2, or 3, the parameters P and IP in the calling sequence are not used and therefore can be dimensioned to be of length one. If i=6 or 7, P must contain a user-supplied coloring vector indicating how the equations and unknowns are to be ordered prior to permuting the system. Preconditioners with names ending with 4 or 5 may be used with or without a permutation. The available choices for $\langle$ precon $\rangle$ are:

RICHi	Richardson's method	(i=1,2,3,4,5)
JACi	Jacobi method	(i=1,2,3,4,5)
LJACi	Line Jacobi method	(i=2,3)
LJACXi	Line Jacobi method (approx. inverse)	(i=2,3)
SORi	Successive Overrelaxation	(i=1,2,3,6,7)
SSORi	Symmetric SOR	(i=1,2,3,6,7)
ICi	Incomplete Cholesky	(i=1,2,3,6)
	(Note: IC7 = BIC7 or BICX7)
MICi	Modified Incomplete Cholesky	(i=1,2,3,6)
	(Note: MIC7 = MBIC7 or MBICX7)
LSPi	Least Squares Polynomial	(i=1,2,3,4,5)
NEUi	Neumann Polynomial	(i=1,2,3,4,5)
LSORi	Line SOR	(i=2,3)
LSSORi	Line SSOR	(i=2,3)
LLSPi	Line Least Squares Polynomial	(i=2,3)
LNEUi	Line Neumann Polynomial	(i=2,3)
BICi	Block Incomplete Cholesky (ver. 1)	(i=2,3,7)
BICXi	Block Incomplete Cholesky (ver. 2)	(i=2,3,7)
MBICi	Modified Block Incomplete Cholesky (ver. 1)	(i=2,3,7)
MBICXi	Modified Block Incomplete Cholesky (ver. 2)	(i=2,3,7)
RSi	Reduced System Method	(i=6,7)

(See Section 5 for a brief description of each of these preconditioners.)