Generate quenched gauge configurations

To learn more about the specifics of the gauge updates, take a look at Gauge Updates (HB and OR). To generate quenched gauge configurations, make the executable generateQuenched. You can then find it under applications/generateQuenched. The example parameter file is found under parameter/generateQuenched.param and looks like this:

#parameter file for generateQuenched
Lattice = 64 64 64 16
Nodes = 1 1 1 1
beta = 6.87361
format = nersc
endianness = auto
stream = a
output_dir = .
nconfs = 1000
nsweeps_ORperHB = 4
nsweeps_HBwithOR = 500

start = one
nsweeps_thermal_HB_only = 500
nsweeps_thermal_HBwithOR = 4000

#conf_nr = 500
#prev_conf = conf_s064t16_b0687361_a_U000500
#prev_rand = rand_s064t16_b0687361_a_U000500

Calling ./generateQuenched generateQuenched.param will output gauge configurations (in nersc format with double precision and 2/3 compression) and their corresponding random number state in the folder output_dir. The output looks like this: e.g.

conf_s064t16_b0687361_a_U000500
conf_s064t16_b0687361_a_U001000
rand_s064t16_b0687361_a_U000500
rand_s064t16_b0687361_a_U001000
...

The configuration number is inferred from nsweeps_HBwithOR, i.e. the first configuration is labeled with the suffix “_U<nsweeps_HBwithOR>” and the following configuration numbers increase in steps of nsweeps_HBwithOR. You should always specify the stream name by setting the parameter stream.

With nconfs you can specify how many configurations should be generated before the program stops. With nsweeps_ORperHB you can specify how many OR updates should be done for each HeatBath update. With nsweeps_HBwithOR you can specify how many HB updates (with nsweeps_ORperHB OR updates per HB) should be done between each saved configuration.

Thermalization parameters

These are required when starting a new stream. With start you can specify with which kind of configuration the thermalization should start. The options are one (all links = unity matrix), fixed_random (all links = same random SU3 matrix) and all_random (a random configuration of SU3 matrices). With nsweeps_thermal_HB_only you can specify how many pure HB updates should be done after the cold start. With nsweeps_thermal_HBwithOR you can specify how many HBOR updates should be done after the pure HB updates. The seed for the random number generator is the time since Unix epoch in milliseconds and is output to stdout.

Parameters for resuming a previous run

With prev_conf you can specify the path of the last configuration you generated. With conf_nr you can specify the number of this last configuration, so that the next configuration’s number will be ( previous_number + nsweeps_ORperHB ). Don’t forget to set stream to the correct value. With prev_rand you can specify the path of the according random number state of that configuration. If you don’t specify this then a new random number state will be generated (The seed for this is also time since Unix epoch in milliseconds and is output to stdout.)