Reproducing identical SOF when recompiling with identical source

[i8087]

Hi,

For example in Quartus Prime Pro 20.4, can I expect to get an identical SOF everytime I recompile a design with no changes in the source?

Is there any documentation on this?

Thanks!

[YuanLi_S_Intel]

Hi,

No, it might not be the same everytime. The internal routing done by fitter will not the same for each recompilation.

However, the size should be the same for same source code.

Regards,

Bruce

[i8087]

Thank you Bruce for your reply.

How about using a fixed seed? Would it still not guarantee identical internal routing?

What's the purpose of using a seed in DSE?

Regarding the size, I could be wrong, but I think I'm getting identical size even for a different source code.

Thanks!

[YuanLi_S_Intel · Accepted solution]

Having fixed seed value doesn’t mean that it will have same routing.

Having different seed value (AKA seed sweeping) is just retry compilation with different starting point. It might yield different timing result.

You may refer to timing user guide for more information ahout it:

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an584.pdf

[i8087]

Thank you for clarification!

[i8087]

What should I do to get an identical SOF when recompile?

[YuanLi_S_Intel]

Having the same source code and same seed value should yield the same SOF. Unless there is a change in source code.