CMMPAK - the capacitance matrix software package The capacitance matrix method (CMM) extends the usefulness of fast elliptic solvers to non-rectangular regions. An iterative variant of CMM developed by D. P. O’Leary and O. Widlhund [Math. Comput. 33, 849-879 (1979; Zbl 0407.65047)] and the author’s paper [ACM Trans. Math. Software 5, 36-49 (1979; Zbl 0394.65029)] makes use of the fact that only a product of the capacitance matrix C and a given vector is required (without any explicit knowledge of the matrix C) and this product can be obtained essentially at the cost of a fast solver. The author presents the outline of the existing CMM package in 2D. For details see the author’s paper, ibid. 9, 117-124 (1983; Zbl 0503.65064). The package consists of three solvers: CMMIMP, CMMEXP and CMMSIX. Each of these solvers computes the finite difference approximation to the solution of the Helmholtz equation in cartesian coordinates -Δu(x,y)+cu(x,y)=f(x,y) on a non-rectangular 2D region. Here Δ is the Laplacian and c is a real constant. On the boundary of this region either the solution (Dirichlet condition) or the normal derivative of the solution is specified (Neumann condition). (Source:

This software is also peer reviewed by journal TOMS.