This is part of the setup module

Loads a library, possibly defining new actions.

It is available only on systems allowing for dynamic loading. It can also be fed with a cpp file, in which case the file is compiled first.

Compulsory keywords

FILE

file to be loaded

Examples

If you have a shared object named extensions.so and want to use the functions implemented within it within PLUMED you can load it with the following syntax

LOAD FILE=extensions.so

As a more practical example, imagine that you want to make a small change to one collective variable that is already implemented in PLUMED, say DISTANCE . Copy the file src/colvar/Distance.cpp into your work directory, rename it as Distance2.cpp and edit it as you wish. It might be better to also replace any occurrence of the string DISTANCE within the file with DISTANCE2, so that both old and new implementation will be available with different names. Then you can compile it into a shared object using

> plumed mklib Distance2.cpp

This will generate a file Distance2.so (or Distance2.dylib on a mac) that can be loaded. Now you can use your new implementation with the following input

# load the new library
LOAD FILE=Distance2.so
# compute standard distance
d: DISTANCE ATOMS=1,10
# compute modified distance
d2: DISTANCE2 ATOMS=1,10
# print them on a file
PRINT ARG=d,d2 FILE=compare-them

You can even skip the initial step and directly feed PLUMED with the Distance2.cpp file: it will be compiled on the fly.

# load the new definition
# this is a cpp file so it will be compiled
LOAD FILE=Distance2.cpp
# compute standard distance
d: DISTANCE ATOMS=1,10
# compute modified distance
d2: DISTANCE2 ATOMS=1,10
# print them on a file
PRINT ARG=d,d2 FILE=compare-them

This will allow to make quick tests while developing your own variables. Of course, after your implementation is ready you might want to add it to the PLUMED source tree and recompile the whole PLUMED.