On Saturday, August 20, 2016 at 1:28:29 AM UTC+1, Robert Dodier wrote:
>
> On 2016-08-19, Montgomery-Smith, Stephen <[email protected] 
> <javascript:>> wrote: 
>
> > sage: integrate(y*e^(-y),y,0,t) 
> > 
> > Huge amount of error messages deleted, followed by: 
> > 
> > ValueError: Computation failed since Maxima requested additional 
> > constraints; using the 'assume' command before evaluation *may* help 
> > (example of legal syntax is 'assume(t>0)', see `assume?` for more 
> details) 
> > Is t positive, negative or zero? 
>
> > However the integral is an analytic function, and exists even if t is 
> > negative or complex. 
>
> On looking into the source code, I see Maxima is trying to classify the 
> type of problem, and using asksign for that. Maxima can actually get the 
> result without resorting to asksign, but it doesn't try that first. The 
> relevant function, if anybody cares, is METHOD-BY-LIMITS in 
> src/defint.lisp. 
>
> I dunno if this is a bug. It is needlessly clumsy but not incorrect. 
>
> I wonder why there is no attempt to compute the antiderivative first.

 

> HTH in some way. 
>
> Robert Dodier 
>
>

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