MonteCarloBarostat¶
-
class
OpenMM
::
MonteCarloBarostat
¶ This class uses a Monte Carlo algorithm to adjust the size of the periodic box, simulating the effect of constant pressure.
This class assumes the simulation is also being run at constant temperature, and requires you to specify the system temperature (since it affects the acceptance probability for Monte Carlo moves). It does not actually perform temperature regulation, however. You must use another mechanism along with it to maintain the temperature, such as
LangevinIntegrator
orAndersenThermostat
.Methods
Create a
MonteCarloBarostat
.Get the default pressure acting on the system (in bar).
Set the default pressure acting on the system.
Get the frequency (in time steps) at which Monte Carlo pressure changes should be attempted.
Set the frequency (in time steps) at which Monte Carlo pressure changes should be attempted.
Get the default temperature at which the system is being maintained, measured in Kelvin.
Set the default temperature at which the system is being maintained.
Get the random number seed.
Set the random number seed.
Returns whether or not this force makes use of periodic boundary conditions.
-
const std::string &
Pressure
()¶ This is the name of the parameter which stores the current pressure acting on the system (in bar).
-
const std::string &
Temperature
()¶ This is the name of the parameter which stores the current temperature at which the system is being maintained (in Kelvin)
-
MonteCarloBarostat
(double defaultPressure, double defaultTemperature, int frequency = 25)¶ Create a
MonteCarloBarostat()
.- Parameters
defaultPressure – the default pressure acting on the system (in bar)
defaultTemperature – the default temperature at which the system is being maintained (in Kelvin)
frequency – the frequency at which Monte Carlo pressure changes should be attempted (in time steps)
-
double
getDefaultPressure
() const¶ Get the default pressure acting on the system (in bar).
- Returns
the default pressure acting on the system, measured in bar.
-
void
setDefaultPressure
(double pressure)¶ Set the default pressure acting on the system. This will affect any new Contexts you create, but not ones that already exist.
- Parameters
pressure – the default pressure acting on the system, measured in bar.
-
int
getFrequency
() const¶ Get the frequency (in time steps) at which Monte Carlo pressure changes should be attempted. If this is set to 0, the barostat is disabled.
-
void
setFrequency
(int freq)¶ Set the frequency (in time steps) at which Monte Carlo pressure changes should be attempted. If this is set to 0, the barostat is disabled.
-
double
getDefaultTemperature
() const¶ Get the default temperature at which the system is being maintained, measured in Kelvin.
-
void
setDefaultTemperature
(double temp)¶ Set the default temperature at which the system is being maintained. This will affect any new Contexts you create, but not ones that already exist.
- Parameters
temp – the system temperature, measured in Kelvin.
-
int
getRandomNumberSeed
() const¶ Get the random number seed. See
setRandomNumberSeed()
for details.
-
void
setRandomNumberSeed
(int seed)¶ Set the random number seed. It is guaranteed that if two simulations are run with different random number seeds, the sequence of Monte Carlo steps will be different. On the other hand, no guarantees are made about the behavior of simulations that use the same seed. In particular, Platforms are permitted to use non-deterministic algorithms which produce different results on successive runs, even if those runs were initialized identically.
If seed is set to 0 (which is the default value assigned), a unique seed is chosen when a
Context
is created from thisForce
. This is done to ensure that eachContext
receives unique random seeds without you needing to set them explicitly.
-
bool
usesPeriodicBoundaryConditions
() const¶ Returns whether or not this force makes use of periodic boundary conditions.
- Returns
true if force uses PBC and false otherwise
-
const std::string &