The code GAMD is a generalization of GAM for the solution of Differential Algebraic Equations of index less than or equal to 3 in the form M y' = f(x,y), with a given initial condition. The methods used in both codes are in the class of Boundary Value Methods (BVMs), namely the Generalized Adams Methods (GAMs) of order 3,5,7,9 with step size control [1,2,3,4].

The code GAMD .

Numerical Experiments .

References .

The code GAMD

The code GAM consists of two files and is Licensed under The GNU General Public License, Version 2 or later. :

- gamd.f90 contains the main subroutines that implement the integration procedure;

- gamda.f90 contains modules and subroutines used by GAMD and some additional linear algebra routines;

If you retrieve the software, please send a message to so that we may keep you updated on any changes. Also any bug reports are appreciated.

Numerical Experiments

The code has been tested on many difficult stiff test problems. For example, those contained in the IVP test set., in Hairer's home page, or in Cash's home page. Some numerical results could be found in the IVP test set web page.

To run the problems in the test set style it is possible to use the driver gamdd.f which contains the main program that must be compiled together with the test set routine of the problem, gamd.f90 and gamda.f90 and the subroutine report.f . See IVP test set web page for a more detailed description of the solver.


[1] L.BRUGNANO, D.TRIGIANTE, Solving Differential Problems by Multistep Initial and Boundary Value Methods, Gordon & Breach, Amsterdam, 1998.

[2] F.IAVERNARO, F.MAZZIA, Block-Boundary Value Methods for the solution of Ordinary Differential Equation. Siam J. Sci. Comput. 21 (1) (1999) 323--339. Full paper.

[3] F.IAVERNARO, F.MAZZIA, Solving Ordinary Differential Equations by Generalized Adams Methods: properties and implementation techniques, proceedings of NUMDIFF8, Appl. Num. Math. 28 (2-4) (1998) 107-126. Full paper.

[4] BVMs Bibliography.

This page is maintained by Francesca Mazzia (

Last Update: November 25, 1999