ChanServ changed the topic of #yosys to: Yosys Open SYnthesis Suite: https://github.com/YosysHQ/yosys/ | Channel logs: https://libera.catirclogs.org/yosys/ | Bridged to #yosys:matrix.org
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<lofty[m]> ysionneau: so, I uncovered something interesting while researching this
<lofty[m]> the default seed is 3549216002486605715, which is more meaningfully 0x3141592653589793.
<lofty[m]> however, nextpnr runs the rng a few times on a seed to get sufficient randomness when seeded, but not by default
<lofty[m]> so --seed 3549216002486605715 will not give you the same result as a run without --seed
<lofty[m]> but anyway, a run without --seed is deterministic.
<Adrien[m]> Thanks lofty, good to know !
<janrinze> lofty[m]: That's good to know, and it's a nicely chosen seed :-D the digits of Pi in 64 bits hex.
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<ysionneau> thanks lofty[m] for the research
<ysionneau> I didn't even notice that the result was deterministic o_o
<Adrien[m]> I'm not sure it is strictly deterministic 🤔
<Adrien[m]> The algorithms probably are, but their implementations (per-uarch contributions, etc) could well use containers sensitive to pointer values, so to virtual memory allocation, which is not reproducible. I have not checked that everywhere in the code, though.
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<lofty[m]> which is why we generally make a point of not storing pointers as keys.
<Adrien[m]> I wasn't aware of this policy, nice, thanks
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<mewt> /23/32
<mewt> sorry
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