bayoumi

double precision FP again

Discussion created by bayoumi on Jul 2, 2008
Latest reply on Jul 9, 2008 by bayoumi
Hi,
I have seen several threads regarding issues with doubles (including my own), and I started to be confused. The summary is:
1- Transcendentals such as exp, log, pow, sin, ... etc are still float then type casted
2- One topic talked about brcc in general truncating doubles from both kernels and C++, and a workaround proposed
3- In my own tests, I have seen that basic add/sub/mult/div did not give any precision errors using brcc, compared to regular 64b CPUs. This is different from what has been reported in # 2 above
4- I never got brcc with brt mode =CPU to work when I use doubles as constants or even when I typecast float constants to doubles. It could be me ...

Can someone summarize the whole issue?

Questions:
1- Is this an SDK issue (i.e. will be fixed anytime soon) or a hardware issue with the ASIC architecture (i.e. no solution soon)?
2- Is there any workarounds or new releases which can get us "real" FP on all kernels (trans. & basic maths)?

I have seen in the posts people doing matrix factorizations (including myself), and those tend to be very sensitive to precision for large scale problems

Thanks
Amr

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