jgroup Subroutine

public subroutine jgroup(N, Ia, Ja, Maxg, Ngrp, Igp, Jgp, Incl, Jdone, Ier)

This subroutine constructs groupings of the column indices of the Jacobian matrix, used in the numerical evaluation of the Jacobian by finite differences.

Input:

N

the order of the matrix.

IA,JA

sparse structure descriptors of the matrix by rows.

MAXG

length of available storage in the IGP array.

Output:

NGRP

number of groups.

JGP

array of length N containing the column indices by groups.

IGP

pointer array of length NGRP + 1 to the locations in JGP of the beginning of each group.

IER

error indicator. IER = 0 if no error occurred, or 1 if MAXG was insufficient.

INCL and JDONE are working arrays of length N.

Arguments

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	N
integer,	intent(in),		dimension(*)	::	Ia
integer,	intent(in),		dimension(*)	::	Ja
integer,	intent(in)			::	Maxg
integer,	intent(out)			::	Ngrp
integer,	intent(inout),		dimension(*)	::	Igp
integer,	intent(out),		dimension(*)	::	Jgp
integer,	intent(inout),		dimension(*)	::	Incl
integer,	intent(inout),		dimension(*)	::	Jdone
integer,	intent(out)			::	Ier