Poisson solver, PoissonCL

CCATSL provides a routine for solving Poisson's equation

$$\m \nabla^2 \psi(x,y)=\zeta(x,y)$$

in a two-dimensional rectangular region, where $\psi$ is specified on the boundary.

	void PoissonCL (	double *psi,
		double *zeta,
		int nx,
		int ny,
		double dlx,
		double dly);

	psi		Array to hold the solution $\psi$. The values on the boundary of the array should be set to the boundary conditions; the rest of the array need not be initialised.
	zeta		Array specifying the function $\zeta$.
	nx		The number of divisions in the lattice in the $x$-direction.
	ny		The number of divisions in the lattice in the $y$-direction. (ny must be a power of 2.)
	dlx, dly		The grid spacing in the $x$ and $y$ directions respectively.

A typical use of PoissonCL might look like

/* /examples/chapter2/poisnex.c */ #include <catam.h> int MainCL(void) { int nx=10; int ny=8; double dlx=0.1; double dly=0.125; double psi[nx][ny]; double zeta[nx][ny]; /* setup zeta */ /* .. */ PoissonCL(psi,zeta,nx,ny,dlx,dly); return 0; }

A complete example using PoissonCL can be found in b09poisn.c.