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Issue #20 new

Special support for tridiagonal systems

Jed Brown
created an issue

Make a Mat subclass for tridiagonal matrix (and block tridiagonal) and write fast sequential solvers for them. Also do fast parallel tridiagonal solvers.

Comments (6)

  1. Jed Brown reporter

    Matthew Knepley It's all the same for tridiagonal. Yes, we could generalize to banded, in which case we could call it SPIKE -- it's just a matter of what language is used to describe it. Anyway, I have no interest in solving with a single system at a time, but solving many different systems in parallel is useful for directional-split algorithms. CRWENO has the property that the reduced system is so well-conditioned that a direct coarse solve doesn't pay off because the iterative solve is guaranteed to converge in a small number of iterations. Different systems may need a direct coarse solve, in which case you have choices for parallelism (addressed in tridiagLU and the paper).

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