ADI Accuracy Parameters

TOMS460 is a FORTRAN77 library which implements ACM TOMS algorithm 460, for determining the relative accuracy obtained in a given number of iterations, or the number of iterations required for a given desired relative accuracy, for an alternating direction implicit iterative linear solution process.

The text of many ACM TOMS algorithms is available online through ACM: or NETLIB:


call adip ( a, b, c, d, iopt, n, itns, dmu, omeh, omev, ier )
where A, B, C and D are lower and upper bounds on the eigenvalues of the two iteration factor matrices; IOPT specifies whether ITNS or DMU is to be computed, N is the dimension of OMEH and OMEV, ITNS is the number of iterations to be performed, DMU is the relative improvement in accuracy, OMEH and OMEV are vectors defining scaling factors to be used to optimize the iteration, and IER is an error flag.


TOMS460 is available in a FORTRAN77 version.


  1. Paul Saylor, James Sebastian,
    Algorithm 460: Calculation of Optimum Parameters for Alternating Direction Implicit Procedures,
    Communications of the ACM,
    October 1973, Volume 16, Number 10, pages 633-635.

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN77 source codes.

Last revised on 03 December 2005.