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XorShiftRng::new should use a non-constant seed #8359

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brson opened this issue Aug 7, 2013 · 4 comments
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XorShiftRng::new should use a non-constant seed #8359

brson opened this issue Aug 7, 2013 · 4 comments
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E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue.

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@brson
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brson commented Aug 7, 2013

It appears that all XorShiftRng's are initialized with the same seed by default. Looks like a foot-gun to me.
@brson
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brson commented Aug 7, 2013

I'm not entirely sure if it's ok to just seed with random numbers or not. Paper is here: http://www.jstatsoft.org/v08/i14/paper

@brson
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brson commented Aug 7, 2013

Apparently bad seeds make xorshift suck, so this may not be easy.

@ghost ghost assigned huonw Aug 7, 2013
@omasanori
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FYI xorshift engines obviously work bad when w = x = y = z = 0.

@lilyball
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From skimming the paper, it suggests that the seeds can be drawn randomly from the set of integers, as long as they're not all 0. Looking at various results for Googling for "xorshift seed" seems to back this up.

@lilyball lilyball mentioned this issue Aug 16, 2013
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bors added a commit that referenced this issue Aug 18, 2013
@bors
auto merge of #8558 : kballard/rust/xorshift-seed, r=cmr
88bd215 
Fixes #8359.
@bors bors closed this as completed in e7b8524 Aug 18, 2013
@brson brson unassigned huonw Jun 16, 2014
flip1995 pushed a commit to flip1995/rust that referenced this issue Jan 27, 2022
@bors
Auto merge of rust-lang#8359 - flip1995:rustup, r=flip1995
a98e7ab 
Rustup

r? `@ghost`

changelog: none
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Give XorShiftRng::new() a random seed lilyball/rust
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@lilyball @brson @omasanori @huonw