Updates to the QCDml
and sharing quark propagators
ILDG12 (May.23,2008)
T. Yoshie for MDWG CCS,Tsukuba
two revisions to QCDml
 new actions
 overlap quark + topology fixing (JLQCD)
 twisted mass quark for non-degenerate doublets
(ETM)
 clover quark with stout link smearing (QCDSF)
 new tag <replicate>
discussions on sharing quark propagators
1
Updates to the QCDml
QCDmlEnsemble1.4.3
(May 11th)
QCDmlEnsemble1.4.4
(May 19th)
2
Overlap quark
overlap operator
m

D(m)   m0  
2

m

  m0   5sign H W ( m0 )
2

Hermitian wilson kernel
with negative mass
HW (m0 )   5 DW (m0 )
approximation
of the sign
function
DW (m0 , x, y )  m0  4
1
  (1    )U  ( x) x   , y  ...
2 
3
• markup minimal set of information for sign
function approximation, because
– sign function approximation affects the physics
– N5 is marked up for domain wall quark action
• plan to support various formulae when they
become necessary
– currently, one choice, approximation with the
Zolotarev rational polynomial
• approx. formulae are in general applied for a
spectrum range
– threshold
– number of eigenmodes
4
specify threshold
<zolotarevSignApprox>
<threshold>
<min>-0.05</min>
<max> 0.05</max>
<method>eigenmode</method>
</threshold>
<nPole>10</nPole>
</zolotarevSignApprox>
nPole: number of poles
all eigenmodes in [-0.05,0.05]
are identified and the sign
function is treated exactly
for the range.
Zolotarev function is applied
outside the threshold range,
i.e. (-L,-0.05) and (0.05,U)
Note:
• Lower/Upper bounds (L/U) of the Zolotarev function are
not marked up. (They are configuration dependent)
• <method> is either “eigenmode” or “ignore”
5
specify number of eigenmodes
<zolotarevSignApprox>
<nEigenmode>1<nEigenmode>
<nPole>variable</nPole>
</zolotarevSignApprox>
eigenvalues
i i  1,2...nEigenmode
are identified and the Zolotarev formula is
applied for the range
U  |  |  max | i |
Note:
• Upper-bound (U) of the Zolotarev approx. is not marked
up. (It is configuration dependent)
• <nPole> is either positive integer or “variable”
6
Topology Fixing
• overlap quark simulation is often accompanied
with topology fixing
• insert an optional block <topologyFixing> in
gluon action section
<iwasakiRGGluonAction>
<glossary/>
<gluonField/>
topology fixing block
<topologyFixing>
</topologyFixing>
<beta>2.30</beta>
<normalisation>cs_sum_to_one</normalisation>
<c0>3.648</c0>
<c1>-0.331</c1>
<c2>0.0</c2>
<c3>0.0</c3>
</iwasakiRGGluonAction>
7
• topology fixing is often realized by multiplying
the Boltzman weight by a fermion determinant
which vanishes for zero eigenmodes.
 dUdd exp( S  S )
  dUdd exp(  S  S
G
F
G
2
)
det[
H
F
W (  m0 )]
 HW2 


det 2

d

d exp( STop )
2 

 HW   
STop    [ DWtm ( )( DW DW )1 DWtm ( )  ]
DWtm (  )  DW (m0 )  i 5 
twisted mass ghost with Wilson kernel
8
det[ H W2 (m0 )]
integer
 HW2 (m0 ) 

det 2
2 
 HW (m0 )   
9
Twisted Mass Mass Split action
• a request from the ETM collab.
– to markup their Nf=2+1+1 ensembles
– usual twisted mass quark for degenerate doubles
(already marked up)
– TM with mass splitting term for 1+1 part
DW  i 51   3
mass twist is in  1 direction
mass split is in  3 direction
numberOfFlavours:
multiple of two
10
NP clover quark with stout link
• a request from the QCDSF Collab. for SLiNC
– clover quark action with stout smeared links only for derivative
terms
– Csw determined non-perturbatively
• no new parameter is necessary, just assign a new name
<fatLinkDerivNpCloverQuarkAction>
<glossary/> <quarkField/>
<numberOfFlavours>2</numberOfFlavours>
<linkSmearing>
<apeLinkBlocking>
<rho0>0.0</rho0> <rho1>0.1</rho1>
</apeLinkBlocking>
<stoutLinkUnitarization/>
<numSmear>1</numSmear>
</linkSmearing>
<kappa>0.1340</kappa> <cSW>1.68</cSW>
</fatLinkDerivNpCloverQuarkAction>
11
<replicate>
• file replication will be proposed by MWWG
• new tag <replicate> in the management section
of ensemble XML
– allow : allow replication
– deny : not allow replication
• <replicate> is optional. If it does not exist, MW
interprets that replication is not allowed.
<management>
<collaboration/>
<projectName/>
<ensembleLabel/>
<publishedAlias/>
<archiveHistory/>
<replicate>allow</replicate>
</management>
12
Sharing Quark Propagators
WG agrees to work for propagator sharing
Everything is still under discussion
13
Collaboration Status
plans
• RBC/UKQCD/LHPC plan to share propagators
with each other
• ETMC plan to share propagators
• Japan has no plan at this moment
file/binary format
• USQCD has several standards
• ETMC has a standard
14
Data Metadata required
• propagator (Data)
– Wilson, KS, DW ….
• source (Data) or source type (Metadata)
• gamma matrix convention (Metadata)
• used file format (Metadata)
– standardize several formats
• reference to conf. i.e. dataLFN (Metadata)
 prototype schemata by C.M.
 face-to-face meeting ?
15
Concluding Remarks
• Latest version of QCDml (Ensemble1.4.4)
meets all community requirements
– visit http://www.ccs.tsukuba.ac.jp/ILDG to get
a sample, which shows you all new features
• Propagator sharing still under discussion
Metadata Working Group
G.Andronico (INFN)
P.Coddington (Adelaide)
C.DeTar (Utah)
R.Edwards (JLAB)
B.Joo (JLAB)
C.Maynard (Edinburgh)
D.Pleiter (NIC/DESY)
J.Simone (FNAL)
T.Yoshie (Tsukuba)
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