[sage-support] Sage Crash Report

2019-03-11 Thread Jacques Avigdor
Thanks Jacques -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googl

[sage-support] Re: simplification options

2019-03-11 Thread Simon King
Hi Michael, On 2019-03-11, Michael Beeson wrote: > I tried various simplification functions.I suppose I could start over, > not using "symbolic expressions" but > declaring K to be a suitable field or ring, maybe a quadratic extension of > the field of rational functions in a. > That is

[sage-support] Re: simplification options

2019-03-11 Thread Eric Gourgoulhon
Le lundi 11 mars 2019 19:05:04 UTC+1, Michael Beeson a écrit : > > I appreciate Eric's post, and I do use subs sometimes, but it makes me > nervous since > it will happily substitute any old thing you tell it to, even an > incorrect thing. So, if your idea > is to check a computation, it i

[sage-support] Re: simplification options

2019-03-11 Thread Nils Bruin
On Monday, March 11, 2019 at 11:05:04 AM UTC-7, Michael Beeson wrote: > > I appreciate Eric's post, and I do use subs sometimes, but it makes me > nervous since > it will happily substitute any old thing you tell it to, even an > incorrect thing. So, if your idea > is to check a computatio

[sage-support] Re: simplification options

2019-03-11 Thread Michael Beeson
I appreciate Eric's post, and I do use subs sometimes, but it makes me nervous since it will happily substitute any old thing you tell it to, even an incorrect thing. So, if your idea is to check a computation, it is a dangerous thing. True, if you put only correct equations in, you'll

[sage-support] Re: simplification options

2019-03-11 Thread Eric Gourgoulhon
What about something like sage: var('p,q,r,a') (p, q, r, a) sage: b = sqrt(1-a^2) sage: eq = (p*a+r*b+q)^2 sage: eq = eq.expand(); eq a^2*p^2 - a^2*r^2 + 2*sqrt(-a^2 + 1)*a*p*r + 2*a*p*q + 2*sqrt(-a^2 + 1)*q*r + q^2 + r^2 sage: b = var('b') sage: eq.subs({sqrt(1-a^2): b}) a^2*p^2 + 2*a*b*p*r - a^

[sage-support] simplification options

2019-03-11 Thread Michael Beeson
In the following example I would like to make Sage realize that (p,q,r) are constants and (a,b) are variables so in the end everything should be expressed as a polynomial in a,b. In particular b^2 should be rewritten as 1-a^2 (b and a are actually sin and cosine of something) but b should no