[metapost] Function defined by a sum
Nicolas FRANCOIS
nicolas.francois at free.fr
Fri Nov 2 12:46:11 CET 2007
Le Fri, 2 Nov 2007 11:21:19 +0100 "Mojca Miklavec"
<mojca.miklavec.lists at gmail.com> a écrit :
> There is no "sum" (unless you define one), but oyu can use "for" loop:
>
> vardef sin(expr xx) = sind(xx*180/3.14) enddef;
>
> vardef f(expr xx,n) =
> save sum;
> sum:=0;
> for i=1 upto n:
> sum := sum+sin(i*(xx))/i;
> endfor;
>
> sum
> enddef;
>
> beginfig(1);
> path p;
> p := (0,0)
> for j=1 upto 700:
> --(j/100,f(j/100,3))
> endfor;
> draw p scaled 1cm;
> endfig;
> end.
Thanks. Someone on another list gave me something more "TeXish" :
vardef sum_sin(expr x,n)=
0
for k:=1 upto n:
+ sin(k*x)/x
endfor
enddef;
I thought something like this could work. But I don't know exactly why.
Is this something like "token replacement", like in TeX ? Where can this
be explained in the Metapost documentation ?
Thanks anyway.
\bye
--
Nicolas FRANCOIS
http://nicolas.francois.free.fr
A TRUE Klingon programmer does NOT comment his code
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