[GRASS-dev] NR licence issue and replacement of G_ludcmp()

Sören Gebbert soerengebbert at gmx.de
Wed May 2 13:41:32 EDT 2007

Hi folks,
i have implemented a pivoting strategy for the direct linear equation solvers
in the gpde library. Now a weighted row pivoting strategy is available for
the LU decomposition solver N_solver_lu() and the gauss elimination N_solver_gauss().

The gpde lu and gauss solver still work in parallel. :)
I have tested the solvers with a Hilbert matrix and v.surf.rst
and it seems to work.

Now 4 gpde solver are available to solve the linear equations
in the rst library, so G_ludcmp() can be replaced. The solvers are:
* N_solver_lu()
* N_solver_gauss()
* N_solver_cg()
* N_solver_bicgstab()

The new lu solver is not as fast as the G_ludcmp() algorithm, which is
related to the parallel approach of the gpde library. But because of
the licence problem with numerical recipes, we need to remove the G_ludcmp() code.

But, i did not had a look at :

yet, which also use the G_ludcmp() algorithm.

The new solvers are available in CVS.

Best regards

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