Further to my delve in the scripts in ~addons/math/misc, I've just
noticed a
misleading comment in pollard.ijs .
The script offers implementations of two Pollard factorisation algorhithms.
The relevant comments are (with a bit of context):
NB. examples:
NB.
NB. ]x=. (,*/) x: p: 1e7 30101
NB. 179424691 351599 63085541930909
NB. pollardpm1 {: x
NB. 351599 335
Well - when you actually run it, this is the result:
]x=. (,*/) x: p: 1e7 30101
179424691 351599 63085541930909
pollardpm1 {: x
179424691 2556
Initially, I thought this might be a bug, but no. The result in the
comment arises from the other function which does pollard rho
factorisation:
pollardrho {: x
351599 335
Indeed, we see that x is defined as the product of the factors found by
the two methods.
No doubt this little slip has been around for some years.
I suggest the comments be amended to read:
NB. examples:
NB.
NB. ]x=. (,*/) x: p: 1e7 30101
NB. 179424691 351599 63085541930909
NB. pollardpm1 {: x
NB. 179424691 2556
et seq... (no changes needed)
Cheers,
Mike
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