but non-identity matrix
l1 0 0 0 ....
0 l2 0 0 ....
0 0 l3 0 ...
. . .
. . .
. . .
And apply the multishift CG to it. Sum the poles and residues.
Insist that this be the same as the exactly taken square root
where l1,l2,l3 >= 0.
Tanh/Zolo * (Cayley/PartFrac/ContFrac) * (Mobius/Shamir/Wilson)
Approx Representation Kernel.
All are done with space-time taking part in checkerboarding, Ls uncheckerboarded
Have only so far tested the Domain Wall limit of mobius, and at that only checked
that it
i) Inverts
ii) 5dim DW == Ls copies of 4dim D2
iii) MeeInv Mee == 1
iv) Meo+Mee+Moe+Moo == M unprec.
v) MpcDagMpc is hermitan
vi) Mdag is the adjoint of M between stochastic vectors.
That said, the RB schur solve, RB MpcDagMpc solve, Unprec solve
all converge and the true residual becomes small; so pretty good tests.
not even SU(3) for now) gauge field. Convergence history is correctly indepdendent of decomposition
on 1,2,4,8,16 mpi tasks.
Found a couple of simd bugs which required fixed and enhanced the Grid_simd.cc test suite.
Implemented the Mdag, M, MdagM, Meooe Mooee schur type stuff in the wilson dop.
cut at Conjugate gradient. Also copied in Remez, Zolotarev, Chebyshev from
Mike Clark, Tony Kennedy and my BFM package respectively since we know we will
need these. I wanted the structure of
algorithms/approx
algorithms/iterative
etc.. to start taking shape.
