Max Alekseyev on Mon, 24 Oct 2011 17:32:42 +0200

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 polisirreducible(f*Mod(1,2)) vs. factormod(f,2)

• To: pari-users@pari.math.u-bordeaux.fr
• Subject: polisirreducible(f*Mod(1,2)) vs. factormod(f,2)
• From: Max Alekseyev <maxale@gmail.com>
• Date: Mon, 24 Oct 2011 19:32:35 +0400
• Delivery-date: Mon, 24 Oct 2011 17:32:42 +0200
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Why polisirreducible(f*Mod(1,2)) is not much faster (if fact, even
slightly slower) than factormod(f,2) on average?
Factoring is an overkill for testing irreducibility but that's
currently not true in PARI/GP.

? q = vector(1000,i,random(10^4));
? for(i=1,#q,factormod( x^q[i]+x+1,2)   )
? ##
***   last result computed in 4min, 6,019 ms.
? for(i=1,#q,polisirreducible( (x^q[i]+x+1)*Mod(1,2)   ) )
? ##
***   last result computed in 4min, 8,812 ms.

Regards,
Max