Regression in integration
- Subject: Regression in integration
- From: Dan Gildea
- Date: Tue, 21 May 2013 15:04:12 -0400
asksign1 should return $pos, not $pn - I think this bug dates to:
commit 5e23e720414b8011f97ae5c31bc304eb151534eb
Author: Rupert Swarbrick <rswarbrick at gmail.com>
Date: Wed Feb 13 23:41:14 2013 +0000
Significantly refactor ASKSIGN1
On Sun, May 19, 2013 at 7:46PM, Barton Willis wrote:
>
>One more thing:
>
>(%i1) integrate(x^n,x);
>
>0> Calling (ASKSIGN1 ((MEXPT SIMP) ((MPLUS SIMP) 1 $N) 2))
>Is n + 1 zero or nonzero?
>
>nonzero;
>
><0 ASKSIGN1 returned $PN
>(%o1) log(x)
>
>The function asksign01 mishandles a return of $pn from asksign1 :
>
>(defun asksign01 (a)
> (let ((e (sign-prep a)))
> (cond ((eq e '$pnz) '$pnz)
> ((member (setq e (asksign1 e)) '($pos $neg) :test #'eq) e)
> (limitp (eps-sign a))
> (t '$zero))))
>
>--Barton