mirror of
https://github.com/paboyle/Grid.git
synced 2025-04-17 09:15:56 +01:00
108 lines
2.9 KiB
Markdown
108 lines
2.9 KiB
Markdown
# Using HMC in Grid
|
|
|
|
These are the instructions to use the Generalised HMC on Grid as of commit `749b802`.
|
|
Disclaimer: Grid is still under active development so any information here can be changed in future releases.
|
|
|
|
|
|
## Command line options
|
|
|
|
(relevant file `GenericHMCrunner.h`)
|
|
The initial configuration can be changed at the command line using
|
|
`--StartingType STARTING_TYPE`, where `STARTING_TYPE` is one of
|
|
`HotStart`, `ColdStart`, `TepidStart`, and `CheckpointStart`.
|
|
Default: `--StartingType HotStart`
|
|
|
|
Example:
|
|
```
|
|
./My_hmc_exec --StartingType HotStart
|
|
```
|
|
|
|
The `CheckpointStart` option uses the prefix for the configurations and rng seed files defined in your executable and the initial configuration is specified by
|
|
`--StartingTrajectory STARTING_TRAJECTORY`, where `STARTING_TRAJECTORY` is an integer.
|
|
Default: `--StartingTrajectory 0`
|
|
|
|
The number of trajectories for a specific run are specified at command line by
|
|
`--Trajectories TRAJECTORIES`, where `TRAJECTORIES` is an integer.
|
|
Default: `--Trajectories 1`
|
|
|
|
The number of thermalization steps (i.e. steps when the Metropolis acceptance check is turned off) is specified by
|
|
`--Thermalizations THERMALIZATIONS`, where `THERMALIZATIONS` is an integer.
|
|
Default: `--Thermalizations 10`
|
|
|
|
Any other parameter is defined in the source for the executable.
|
|
|
|
## HMC controls
|
|
|
|
The lines
|
|
|
|
```
|
|
std::vector<int> SerSeed({1, 2, 3, 4, 5});
|
|
std::vector<int> ParSeed({6, 7, 8, 9, 10});
|
|
```
|
|
|
|
define the seeds for the serial and the parallel RNG.
|
|
|
|
The line
|
|
|
|
```
|
|
TheHMC.MDparameters.set(20, 1.0);// MDsteps, traj length
|
|
```
|
|
|
|
declares the number of molecular dynamics steps and the total trajectory length.
|
|
|
|
|
|
## Actions
|
|
|
|
Action names are defined in the directory `Grid/qcd/action`.
|
|
|
|
Gauge actions list (from `Grid/qcd/action/gauge/Gauge.h`):
|
|
|
|
```
|
|
WilsonGaugeActionR;
|
|
WilsonGaugeActionF;
|
|
WilsonGaugeActionD;
|
|
PlaqPlusRectangleActionR;
|
|
PlaqPlusRectangleActionF;
|
|
PlaqPlusRectangleActionD;
|
|
IwasakiGaugeActionR;
|
|
IwasakiGaugeActionF;
|
|
IwasakiGaugeActionD;
|
|
SymanzikGaugeActionR;
|
|
SymanzikGaugeActionF;
|
|
SymanzikGaugeActionD;
|
|
```
|
|
|
|
```
|
|
ConjugateWilsonGaugeActionR;
|
|
ConjugateWilsonGaugeActionF;
|
|
ConjugateWilsonGaugeActionD;
|
|
ConjugatePlaqPlusRectangleActionR;
|
|
ConjugatePlaqPlusRectangleActionF;
|
|
ConjugatePlaqPlusRectangleActionD;
|
|
ConjugateIwasakiGaugeActionR;
|
|
ConjugateIwasakiGaugeActionF;
|
|
ConjugateIwasakiGaugeActionD;
|
|
ConjugateSymanzikGaugeActionR;
|
|
ConjugateSymanzikGaugeActionF;
|
|
ConjugateSymanzikGaugeActionD;
|
|
```
|
|
|
|
Each of these action accepts one single parameter at creation time (beta).
|
|
Example for creating a Symanzik action with beta=4.0
|
|
|
|
```
|
|
SymanzikGaugeActionR(4.0)
|
|
```
|
|
|
|
Scalar actions list (from `Grid/qcd/action/scalar/Scalar.h`):
|
|
|
|
```
|
|
ScalarActionR;
|
|
ScalarActionF;
|
|
ScalarActionD;
|
|
```
|
|
|
|
The suffixes `R`, `F`, `D` in the action names refer to the `Real`
|
|
(the precision is defined at compile time by the `--enable-precision` flag in the configure),
|
|
`Float` and `Double`, that force the precision of the action to be 32, 64 bit respectively.
|