# The 34th International Symposium on Lattice Field Theory (Lattice 2016)

24-30 July 2016
Highfield Campus, University of Southampton
Europe/London timezone

## Hierarchically deflated conjugate residua

26 Jul 2016, 19:00
1h
Highfield Campus, University of Southampton

#### Highfield Campus, University of Southampton

Highfield Campus, Southampton SO17 1BJ, UK
Poster Algorithms and Machines

### Speakers

Dr Azusa Yamaguchi (Software Architect)Prof. Peter Boyle (University of Edinburgh)

### Description

Hierarchically deflated conjugate residual We present a new class of multigrid solver algorithm suitable for the solution of 5d chiral fermions such as Domain Wall fermions and the Continued Fraction overlap. Unlike HDCG \cite{arXiv:1402.2585}, the algorithm works directly on a nearest neighbour fine operator. The fine operator used is Hermitian indefinite, for example $\Gamma_5 D_{dwf}$, and convergence is achieved with an indefinite matrix solver such as outer iteration based on conjugate residual. As a result coarse space representations of the operator remain nearest neighbour, giving an 8 point stencil rather than the 81 point stencil used in HDCG. It is hoped this may make it viable to recalculate the matrix elements of the little Dirac operator in an HMC evolution.

### Primary author

Dr Azusa Yamaguchi (Software Architect)

### Co-author

Prof. Peter Boyle (University of Edinburgh)

### Presentation Materials

There are no materials yet.
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