[petsc-dev] MATCOMPOSITE as fallback for matrix-matrix multiplication
Isaac, Tobin G
tisaac at cc.gatech.edu
Sat Mar 9 15:42:36 CST 2019
Let's say I want to do Newton-Krylov on some DAG of computations.
Building the Jacobian is programmatic from the chain rule, requiring
just a lot of matrix-matrix multiplications in the correct sequence.
If it really is more efficient for two Jacobians to be contracted into
a matrix with random access, that's great, but if it's not, or if
the appropriate implementation of MatMatMult_X_Y does not exist,
having a MATCOMPOSITE is better than nothing.
So why not make MATCOMPOSITE something that our matrix-matrix
multiplication routines return when a specialization isn't found?
It moves the "Not Implemented" warning from MatMatMult() to
whenever I try to do something other than multiply with the output,
but in some situations that's desirable.
I'd be interested to hear what people think.
Thanks,
Toby
More information about the petsc-dev
mailing list