Arpack.jl icon indicating copy to clipboard operation
Arpack.jl copied to clipboard

explicittransform does an unintuitive thing

Open PetrKryslUCSD opened this issue 4 years ago • 2 comments

I have two symmetric PD sparse matrices, and I call

d, v, nconv = eigs(Symmetric(K+OmegaShift*M), Symmetric(M); nev=neigvs, which=:SM)

Clearly it is reasonable to expect the results to be normalized relative to the matrix B. This however does not happen since the designation of the matrices as symmetric is lost due to explicittransform being set internally to :shiftinvert.
This is a violation of backward compatibility.

PetrKryslUCSD avatar May 23 '21 17:05 PetrKryslUCSD

Also, allowing explicit transform to happen appears to carry with it a significant performance penalty. In the above case the execution time more than doubled.

PetrKryslUCSD avatar May 25 '21 15:05 PetrKryslUCSD

See #120

ViralBShah avatar Nov 17 '21 15:11 ViralBShah