On 12/2/11 4:32 PM, Stavros Macrakis wrote:
> Forget about the error message... the values are completely wrong for
> x>35 or so. Serious bug!
Haha! I think I know how to fix this. Si can be expressed in terms of
the incomplete gamma function and I think that works pretty well. At
least for large x, it stays near %pi/2.
Ray
>
> -s
>
> On Fri, Dec 2, 2011 at 18:56, Edwin Woollett <woollett at charter.net
> <mailto:woollett at charter.net>> wrote:
>
> I am getting an error message when evaluating
> sin and cosine integral functions
> expintegral_si(x) and expintegral_ci(x)
> for largish args:
> ---------------------------------
> Maxima 5.25.1 http://maxima.sourceforge.net
> using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)
>
>
> (%i1) [expintegral_si(100.0),expintegral_ci(100.0)];
>
> (%o1) [3.8412020891467011E+24,3.3074885133765204E+23]
>
> (%i2) expintegral_si(1000.0);
>
> expintegral_e: series failed.
> -- an error. To debug this try: debugmode(true);
>
> (%i3) expintegral_ci(1000.0);
>
> expintegral_e: series failed.
> -- an error. To debug this try: debugmode(true);
>
> (%i4)
> ----------------------
>
> Ted Woollett
>
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