TUFLOW Message 0250: Difference between revisions
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|type=[[ERROR]]
|message_desc=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: <br>
<tt>
<font color="blue"><tt>Grid Size (X,Y) </tt></font> <font color="red"><tt>==</tt></font><tt> 2, 4</tt><br>
<font color="blue"><tt>Cell Size </tt></font> <font color="red"><tt>==</tt></font><tt> 1</tt>
</tt></br>
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.<br>
For Quadtree the number of threads must be less than the number of cells.
|suggestions=Review model size definition in the TGC file. <br>
If model is intended to be small, the number of CPU threads may need to be reduced. E.g. set <font color="blue"><tt>Hardware </tt></font> <font color="red"><tt>==</tt></font><tt> CPU</tt> and <font color="blue"><tt>CPU Threads </tt></font> <font color="red"><tt>==</tt></font><tt> 1</tt> in the TCF file.
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