massflow seed command

Syntax

massflow seed <i >

Set the random seed used by MassFlow. All random decisions made by MassFlow (marker placement within a block, primary fragment size and tensile strength sampled when a marker is created, the shear-fragmentation percentile, fines-migration percolation distance, void-diffusion collapse direction, air-gap jitter and the column visiting order used by free-surface rilling) are derived from this single integer. The default value is 10000 and is restored by model new. If i is omitted or 0, the default 10000 is used.

Two runs of the same data file with the same seed produce identical results, independent of the number of threads (program thread), of restarting the program, and of saving and restoring the model (the seed and the state of the MassFlow random stream are archived in the save file). A different seed gives a different, equally reproducible realization of the same statistical model.

The command may be given anywhere before massflow compute, including after a model restore to continue a run with a new realization. The seed in effect is printed at the start of every massflow compute.

Note

model random does not affect MassFlow when used coupled with FLAC3D. The kernel random generator shared by FLAC3D and FISH advances on every draw made anywhere in the program, so its state at the time MassFlow starts is not a reliable record of the number given to model random. MassFlow therefore keeps its own seed, set only by this command. Use model random for FLAC3D features and massflow seed for MassFlow.

Example

model new
massflow mine-block import 'blocks.csv'
...
massflow seed 12345
massflow clean
massflow compute