Alternate Run Modes:Monte Carlo Runs

Monte Carlo Runs

The monte carlo mode is most useful for calibrating on a supercomputer where you can dedicate hundreds or thousands of processors to running various versions of a GSSHA^TM simulation. The monte carlo run mode is set up similar to the SCE calibration mode.

To run GSSHA^TM in monte carlo mode, use the command line format

gssha -m[# runs] [mc.in]

where [mc.in] is the name of the monte carlo input file and [# runs] is the number of monte carlo runs to make. For running in MPI mode, use the command line

gssha -m[# runs] [# proc per run] [mc.in]

where [# proc per run] is the number of logical processors to dedicate to an individual run. Currently this number should be set to 1. For both command lines, there is no space between the -m and the number of runs.

For example, to run 1000 runs in either serial or OpenMP mode, use the command line:

gssha -m1000 mc.in

The monte carlo input file has the following format:

[Projname.prj]
[params.in]
[observed.dat]
[# of parameters]
[lower bound 1] [upper bound 1]
[lower bound 2] [upper bound 2]
...
[lower bound N] [upper bound N]

Where

Projname.prj is the name of the GSSHA project file

params.in is the name of the paramters file

observed.dat is the name of the observed data file.

Just like for the SCE calibration file, the order of the parameter bounds needs to be the same in the parameters file as well as the monte carlo input file. The observed data file has the same format for the SCE calibration mode as for the monte carlo mode.

Single-run mode

The single-run monte carlo mode is used for manual calibration when you wish GSSHA to compute the cost function and other objective functions. The monte carlo input file is as follows:

[Projname.prj]
[params.in]
[observed.dat]
[# of parameters]
[value for parameter 1]
[value for parameter 2]
...
[value for parameter N]

You must run GSSHA in the command line like this:

gssha -m1 mc.in

Comments

You can also include comments after the values lines in the monte carlo input file. Comments should begin with a '#'.

[Projname.prj]
[params.in]
[observed.dat]
[# of parameters]
[lower bound 1] [upper bound 1] #parameter comment
[lower bound 2] [upper bound 2] #parameter comment
...
[lower bound N] [upper bound N] #parameter comment

[params.in]
[observed.dat]
[# of parameters]
[value for parameter 1] #parameter comment
[value for parameter 2] #parameter comment
...
[value for parameter N] #parameter comment