WHAM problems

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David Chalmers

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Mar 26, 2025, 7:38:43 AMMar 26

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Hi All,

We have run an umbrella sampling simulation of a molecule traversing a membrane and are trying to process the trajectories. We are getting an error from the WHAM_HISTOGRAM step. Thanks for any help anyone can provide!

David

This run has 4 trajectories.

The plumed input file is:

plumed.dat

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MOLINFO STRUCTURE=b0002_2.pdb

solu: GROUP NDX_FILE=index.ndx NDX_GROUP=SOLU

memb: GROUP NDX_FILE=index.ndx NDX_GROUP=MEMB

c1: COM ATOMS=solu

c2: COM ATOMS=memb

d1: DISTANCE ATOMS=c1,c2 COMPONENTS

umbrella: RESTRAINT ...

ARG=d1.z KAPPA=150.0

AT=@replicas:{4.0 3.9 3.8 3.7}

...

PRINT STRIDE=1000 ARG=d1.z,umbrella.bias FILE=COLVAR

hh: WHAM_HISTOGRAM ARG=d1.z BIAS=umbrella.bias TEMP=300 GRID_MIN=-3.7 GRID_MAX=4.0 GRID_BIN=50

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The error we get is:

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PLUMED: (core/Action.cpp:240) void PLMD::Action::error(const string&) const

PLUMED: ERROR in input to action REWEIGHT_WHAM with label hh_weights : Too many iterations in WHAM