Ha Tran on Thu, 13 Jun 2013 09:42:41 +0200

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Dear helpers,

I have a problem in using the function "ploth"  in pari gp. 

Actually, I need to compute a infinite sums:

ff(x,vp,re,wp)=log (sum(s1=-\infinity,\infinity,sum(s2=-\infinity,\infinity, exp(g(x,vp,re,wp))))  for a<x<b;

and with the accuracy epsilon =10^(-5), by using a function to limit this sum, let call limitshortvec(x,vp,re), I have the bounds of s1 and s2 (lis1 and lis2), then I define:

ff(x,vp,re,wp)=limitshortvec(x,vp,re);log (sum(s1=-lis1,lis1,sum(s2=-lis2,lis2, exp(g(x,vp,re,wp))))  for a<x<b;

Finally, I have to "link" these functions "ff"" together, for example:

h(x)=if(a<=x &&x<=b,ff(x,vp1,re1,wpr1),if(b<x &&x<=c,ff(x,vp2,re2,wpr2)))

then plot h:


then Pari gp gives an announcement:

“1347953757 [main] gp 6648 child_copy: linked dll data write copy failed, 0x2CC000..0x2CF1B0, done 0, windows pid 6648, Win32 error 487” 

However, it is ok with the function “plot”.

Moreover, if I delete the function “limitshortvec” in ff and just compute a finite sum, for instance:

ff(x,vp,re,wp)= log (sum(s1=-10,10,sum(s2=-10,10, exp(g(x,vp,re,wp))))  

then this function works well. 

Therefore, I do not know what problem is, if the function h is not well defined or window system or Pari gp has some errors. (The fact that I can use the function “plot” for h showing that the function h is still well defined in some way). 

I wonder if there is anyone who can help me correct this problem.

Thank you so much.

Ha Tran.