Expm1() problems - precision
Hi Guys. I created an OpenCL program to execute some mathematic operations. It worked fine in AMD video card (result matched with wolframalpha, for instance) but when I tried to use a computer with a Quadro 600 video card and linux, my program returned values that didn't matched the precision we expected for function expm1(x). I thought my video card had a problem, but I tried in another machine with quadro 600 and linux and obtained the same results from the first one. I tried run this program in Windows and I don't have this problem. Some examples: operation: expm1(input) output: -0.727467 expected:-0.727468 input: -1.3 operation: expm1(input) output: 0.733252 expected:0.733253 input: 0.55 operation: expm1(input) output: 0.822116 expected:0.822119 input: 0.6 operation: expm1(input1) output: 0.915535 expected:0.915541 input 1: 0.65 operation: expm1(input1) output: 991.271 expected:991.275 input 1: 6.9 I've alread researched about this function ulp, but the maximun value is 1(full range) As far as I could check, this seems to be a problem with the linux driver. Does any of you know about such a problem ? Thanks and Regards Rafael R. Machado
Hi Guys.

I created an OpenCL program to execute some mathematic operations. It worked fine in AMD video card (result matched with wolframalpha, for instance) but when I tried to use a computer with a Quadro 600 video card and linux, my program returned values that didn't matched the precision we expected for function expm1(x).
I thought my video card had a problem, but I tried in another machine with quadro 600 and linux and obtained the same results from the first one.
I tried run this program in Windows and I don't have this problem.

Some examples:

operation: expm1(input)
output: -0.727467
expected:-0.727468
input: -1.3

operation: expm1(input)
output: 0.733252
expected:0.733253
input: 0.55

operation: expm1(input)
output: 0.822116
expected:0.822119
input: 0.6

operation: expm1(input1)
output: 0.915535
expected:0.915541
input 1: 0.65

operation: expm1(input1)
output: 991.271
expected:991.275
input 1: 6.9

I've alread researched about this function ulp, but the maximun value is 1(full range)

As far as I could check, this seems to be a problem with the linux driver. Does any of you know about such a problem ?

Thanks and Regards
Rafael R. Machado

#1
Posted 02/14/2014 11:31 AM   
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