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2025.1 floating point issue

may_ka
Beginner
‎04-13-2025 10:47 PM
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Hi,

 

after installing the 2025.1 oneapi basekit and hpckit release I have stumbled over substantial differences in calculation results.

 

After some digging it turned out that the culprit is icpx.

Doing some comparisons for the respective calculations I found that g++ 14.2, clang++ 19.1, icpx 2024.0.2 all deliver the same results irrespective of the floating point model (i.e. irrespective of whether "-ffast-math" is set or not). icpx 2025.1 also delivers the same results but only when using "-O0 -g", or "-O3 -fno-fast-math".

 

Is this a bug ....... or is icpx 2025.1 requiring different flags?

 

The calculations involve multiplication, addition, subtraction, square root, power, and absolute value, where for the last there std::sqrt, std::pow and std::abs is used.

 

Any idea?

 

Thanks

 

OS: Linux

Kernel: 6.14

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Sravani_K_Intel
Moderator
‎04-16-2025 10:03 AM
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Could you provide a test case that demonstrates the differences in results?

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