RESTART
This is part of the setup module

Activate restart.

This is a Setup directive and, as such, should appear at the beginning of the input file. It influences the way PLUMED treat files open for writing (see also Files).

Notice that it is also possible to enable or disable restart on a per-action basis using the RESTART keyword on a single action. In this case, the keyword should be assigned a value. RESTART=AUTO means that global settings are used, RESTART=YES or RESTART=NO respectively enable and disable restart for that single action.

Attention
This directive can have also other side effects, e.g. on METAD and PBMETAD and on some analysis action.
Examples

Using the following input:

Click on the labels of the actions for more information on what each action computes
tested on v2.8
d: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between.
=1,2 PRINT
ARG
the input for this action is the scalar output from one or more other actions.
=d
FILE
the name of the file on which to output these quantities
=out

a new 'out' file will be created. If an old one is on the way, it will be automatically backed up.

On the other hand, using the following input:

Click on the labels of the actions for more information on what each action computes
tested on v2.8
RESTART 
d: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between.
=1,2 PRINT
ARG
the input for this action is the scalar output from one or more other actions.
=d
FILE
the name of the file on which to output these quantities
=out

the file 'out' will be appended.

In the following case, file out1 will be backed up and file out2 will be concatenated

Click on the labels of the actions for more information on what each action computes
tested on v2.8
RESTART 
d1: DISTANCE 
ATOMS
the pair of atom that we are calculating the distance between.
=1,2 d2: DISTANCE
ATOMS
the pair of atom that we are calculating the distance between.
=1,2 PRINT
ARG
the input for this action is the scalar output from one or more other actions.
=d1
FILE
the name of the file on which to output these quantities
=out1
RESTART
allows per-action setting of restart (YES/NO/AUTO)
=NO PRINT
ARG
the input for this action is the scalar output from one or more other actions.
=d2
FILE
the name of the file on which to output these quantities
=out2

In the following case, file out will backed up even if the MD code thinks that we are restarting. Notice that not all the MD code send to PLUMED information about restarts. If you are not sure, always put RESTART when you are restarting and nothing when you aren't

Click on the labels of the actions for more information on what each action computes
tested on v2.8
RESTART 
NO
( default=off ) switch off restart - can be used to override the behavior of the MD engine
d1: DISTANCE
ATOMS
the pair of atom that we are calculating the distance between.
=1,2 PRINT
ARG
the input for this action is the scalar output from one or more other actions.
=d1
FILE
the name of the file on which to output these quantities
=out1
Glossary of keywords and components
Options
NO

( default=off ) switch off restart - can be used to override the behavior of the MD engine