# Machine Specific Notes¶

Here we will mention some miscellaneous notes on specific machines. This is merely a list of pitfalls or things we have found useful, and by no means a replacement to the documentation.

## NICS: Kraken¶

http://www.nics.tennessee.edu/computing-resources/kraken

### Important¶

Serious errors have been found with a few Enzo routines when using -O2 and the PGI compilers on Kraken. Use with caution.

### Trace Trap Flags¶

Useful for debugging, but slows the code down. You can find this info in the pgCC man page. (Not all compilers have decent trace trapping, so it deserves a mention here.)

-Ktrap=[option,[option]...]
Controls the behavior of the processor when
exceptions occur.  Possible options include
-Ktrap=divz  Trap on divide by zero.
-Ktrap=fp  Trap on floating point exceptions.
-Ktrap=align Trap on memory alignment errors, currently ignored
-Ktrap=denorm Trap on denormalized operands.
-Ktrap=inexact Trap on inexact result.
-Ktrap=inv Trap on invalid operands.
-Ktrap=none (default)   Disable all traps.
-Ktrap=ovf Trap on floating point overflow.
-Ktrap=unf Trap on floating point underflow.