HybridForceField #
HybridForceField connects two different forcefields.
\[V = \lambda V_1 + (1 - \lambda) V_2\]The topology can be different.
Example input #
First, you need to define and name several forcefields to be connected.
Then, set forcefields.type = "Hybrid" in [simulator] table and provide lambda value.
The first and the second [[forcefields]] table will be the \( V_1 \)
and \( V_2 \)
in the above equation, respectively.
[simulator]
type = "MolecularDynamics"
boundary_type = "Unlimited"
precision = "double"
delta_t = 0.1
total_step = 1000000
save_step = 1_000
seed = 2859805901
integrator.type = "BAOABLangevin"
integrator.gammas = [
# ...
]
forcefields.type = "Hybrid"
forcefields.lambda = 0.5
# ...
[[forcefields]] # V1
[[forcefields.local]]
# ...
[[forcefields]] # V2
[[forcefields.local]]
# ...
make λ dynamic #
We can integrate \(\lambda\)
over time by considering it as a dynamic variable.
To do that, set forcefields.lambda = "dynamic" and define dynamic_variables.lambda in [[systems]].
The coordinate, velocity, force are saved in the .ene file.
Also, you can apply a harmonic potential \(k(\lambda - \lambda_0)^2\) to \(\lambda\) .
[simulator]
type = "MolecularDynamics"
boundary_type = "Unlimited"
precision = "double"
delta_t = 0.1
total_step = 1000000
save_step = 1_000
seed = 2859805901
integrator.type = "BAOABLangevin"
integrator.gammas = [
# ...
]
forcefields.type = "Hybrid"
forcefields.lambda = "dynamic" # make lambda dynamic
forcefields.v0_lambda = 1.0 # k(v - v0)^2
forcefields.k_lambda = 100.0 # k(v - v0)^2
# ...
[[systems]]
attributes.temperature = 300.0
dynamic_variables.lambda = {x = 1.0, m = 1000.0, gamma = 1e-5, boundary = "Repulsive", lower = 0.0, upper = 1.0}
[[forcefields]] # V1
[[forcefields.local]]
# ...
[[forcefields]] # V2
[[forcefields.local]]
# ...