Problem of 'missing stage' in colvars.state file

From: Shaon Chakrabarti (
Date: Tue Jun 19 2012 - 12:15:51 CDT

Hi NAMD experts,

  I am running a simulation with two Colvar components
and harmonic biases applied to both. When I try to
restart these simulations using the colvars.state file, I
face a problem sometimes, that causes the restart to crash.

The error in the log file is the following :
  "colvars: Error: current stage is missing from the restart"

I checked the colvars.state file, and indeed, the line with 'stage'
was missing from one of the colvars component ( please look at
the colvars.state file contents that I'm pasting below). What
is surprising however, is that a missing 'stage' does not always
mean a crashed simulation! Some of the restarts are running
perfectly even though their colvars.state file had a 'stage' line missing!

Can someone please explain to me what that 'stage' line means
in the colvars.state file, why it appears in the file sometimes
but not everytime and why some of the restarts crash when
the stage line fails to appear?

Thank you,

*******colvars.state file for a restart that crashed**********

configuration {
  step 500000
  dt 2.000000e+00

colvar {
  name Rg
  x 4.19555478295841e+00

colvar {
  name coord
  x 8.63693673715731e+02

harmonic {
  configuration {
    name umbrella1
    stage 0

harmonic {
  configuration {
    name umbrella2

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