TUFLOW Message 0250

TUFLOW Message
ERROR 0250 - Too many CPU threads for model size, thread limit: <>.

Alternate Message
NA

Message Type
ERROR

Description
When running HPC models (not including quadtree) over a number of processing devices (CPU threads or GPU cards) the model is split and each device gets an equal portion of the model to solve (split along the model x-dimension) . Running very small models can mean that more compute devices than model columns are used. For example in the .tgc the following commands:
Grid Size (X,Y) == 2, 4
Cell Size == 1
Creates a model with 2 columns (in the x-direction) and 4 rows (in the y-direction). Running the above model with CPU Threads == 4 would give ERROR 0250. The minimum number of model columns for a device is 4, so a model with 10 columns could run on 2 CPU, but any more would result in ERROR 0250. Note: there is little benefit in running small models on large numbers of threads, and this may actually cause a slow down in the simulation speed due to computational overhead.
For Quadtree the number of threads must be less than the number of cells.

Suggestions
Review model size definition in the TGC file.
If model is intended to be small, the number of CPU threads may need to be reduced. E.g. set Hardware == CPU and CPU Threads == 1 in the TCF file.

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