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PARI/gp
#14
Hi, again!

I would like to algoritmize the fractional derivatives and integrals, but here are some problems.
This is my code:

Code:
int1(f,a,b,h)={return(sum(k=floor(min(a*h,b*h)),ceil(max(a*h,b*h)),sign(b-a)*subst(f,x,k/h)/h));}

Stein(f,n,a,h)={return(der1(int1(f,0,a,h),a,h)/gamma(1-n));}

So e. g. D^2.5 x^2.5 = gamma(2.5-1) = Stein(x^2.5,2.5,0,1000.0), but it returns with this error message:
domain error in gpow [irrational exponent]: valuation != 0

Furthermore my Stein function return with ~0 in other cases. Why?

EDIT:
Here is the original formula:
https://wikimedia.org/api/rest_v1/media/...cc722c1f49
Oops, it looks I forgot some things from the my algorithm. It will be checked soon.

EDIT2:
Here is the new algorithm which is not working, too:
Code:
Stein(f,n,a,h)={return(der1(int1(subst(f,x,u)/(x-u)^n,0,a,h),a,h)/gamma(1-n));}
Xorter Unizo
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Messages In This Thread
PARI/gp - by Xorter - 04/17/2017, 09:48 AM
RE: PARI/gp - by Gottfried - 04/17/2017, 04:27 PM
RE: PARI/gp - by Xorter - 04/17/2017, 05:53 PM
RE: PARI/gp - by Xorter - 04/17/2017, 07:05 PM
RE: PARI/gp - by sheldonison - 04/18/2017, 05:37 AM
RE: PARI/gp - by Xorter - 04/18/2017, 09:02 AM
RE: PARI/gp - by Xorter - 11/20/2017, 08:21 PM
RE: PARI/gp - by Gottfried - 11/21/2017, 12:51 AM
RE: PARI/gp - by Xorter - 11/21/2017, 01:31 PM
RE: PARI/gp - by Gottfried - 11/21/2017, 03:05 PM
RE: PARI/gp - by Xorter - 11/21/2017, 03:50 PM
RE: PARI/gp - by Gottfried - 11/21/2017, 08:24 PM
RE: PARI/gp - by Xorter - 11/23/2017, 02:48 PM
RE: PARI/gp - by Xorter - 05/08/2018, 08:56 PM
RE: PARI/gp - by Xorter - 07/09/2018, 08:54 AM

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