Christian Hoffmann on Tue, 07 May 2013 23:43:05 +0200

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Re: silly long list of suggestions

Am 15.04.13 19:52, schrieb Joerg Arndt:
Thanks for the swift reply.

* Bill Allombert <> [Apr 15. 2013 18:24]:
On Mon, Apr 15, 2013 at 05:49:57PM +0200, Joerg Arndt wrote:
Hello Joerg,
thanks for your suggestions.

Pade approximant for series, see
(looks doable)
Did you try bestappr and bestapprPade ?

I was afraid I'd touch things actually possible already...

? bestapprPade(sin(x),5)
%6 = (911*x^11 - 250734*x^9 + 29604960*x^7 - 1665195840*x^5 + 39178339200*x^3 - 250637587200*x)/(-8981280*x^4 - 2594592000*x^2 - 250637587200)

This gives :

? bestapprPade(sin(x),5)
  ***   at top-level: bestapprPade(sin(x),
  ***                 ^--------------------
  ***   not a function in function call

on my machine:

          GP/PARI CALCULATOR Version 2.5.3 (released)
          i386 running darwin (x86-64/GMP-5.0.5 kernel) 64-bit version
                    compiled: Mar 19 2013, gcc-4.7.1 (GCC)

An option to have polynomials printed "constant

This is much neater in some cases, e.g., for rational
generating functions.
Well, you can convert your polynomial to a power series for display.
Won't work with fractions of polynomials
(as other things I suggested, there are workarounds;
I only made such suggestions when I thought it would
lead to more expressive Pari code).

Option to have Vec(series) _not_ drop initial zeros.
Try Vec(series,n)
Second arg determines length of vector, not initial index.

I'd like to be able to have
? Vec(x^3/(1-x)+O(x^6))
\\ give
%4 = [0, 0, 0, 1, 1, 1]
\\ and not
%4 = [1, 1, 1]

My usual workaround is
v = Vec(x^3/(1-x)+O(x^6) +'c0);
v[1] -= 'c0;
... but that's at least a bit noisy.

Best,  jj

Christian W. Hoffmann,
CH - 8915 Hausen am Albis, Switzerland
Rigiblickstrasse 15 b, Tel.+41-44-7640853,,