Solve a PDE in 3D domain using ADI method. Use provided slices to solve for certain regions.

  • d – right hand side vector

  • x – vector to be solved

  • s1 – index triples for x-axis, that define a 1d slice

  • s2 – index triples for y-axis, that define a 1d slice

  • s3 – index triples for z-axis, that define a 1d slice

  • a – equation coefficient, proportional to diffusivity

  • boundaries – type of boundary conditions: 0 for 0 at boundaries, 1 for fixed boundaries, 2 for no flow through boundaries