[GiNaC-list] Problem about series

[Feng Feng]

I am sorry for that I didn't make it clear.

the test program shows that s1 output is Order(ep^(-1)),
there is no other term in the output, so s1 output indicates
that there is no ep^(-2) in expr, I am not sure I interpret  the 
s1 output correctly or not? 

PS: from s2 output indicates that there is an ep^(-2) term in expr.

Thanks very much!
Best Regards!
Feng



> -----原始邮件-----
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> 发送时间: 2019-04-12 18:00:03 (星期五)
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> 主题: GiNaC-list Digest, Vol 140, Issue 5
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>    1. Re: Problem about series (Richard B. Kreckel)
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> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Thu, 11 Apr 2019 23:29:23 +0200
> From: "Richard B. Kreckel" <kreckel at in.terlu.de>
> To: ginac-list at ginac.de
> Subject: Re: [GiNaC-list] Problem about series
> Message-ID: <920c06c9-7a44-f2eb-43d3-2b46adbae6e6 at in.terlu.de>
> Content-Type: text/plain; charset=utf-8
> 
> Feng Feng,
> 
> Sorry, I don't see what's wrong with this.
> 
> On 08.04.19 01:00, Feng Feng wrote:
> > Hi, I got a problem ?about the series function,
> > I used the following test code(see below or the attached file),
> > the s1 output only gives Order(ep^(-1)), while s2 output indicates that
> > there is a 1/ep^2 term, so the s1 is not correct or I used the series in
> > a wrong way?
> > 
> > Thanks a lot!
> > 
> > #include <ginac/ginac.h>
> > 
> > using namespace GiNaC;
> > using namespace std;
> > 
> > int main(int argn, char** args) {
> > ? ? symbol x1("x1"),x2("x2"),x3("x3"),x4("x4");
> > ? ? symbol ep("ep");
> > ? ? ex expr = -2*pow(x1,-1 + ep)*(exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)*
> > ? ? ? pow(1 + x3 + x4 + x3*x4,-3*ep)*
> > ? ? ? pow(1 + x2 + x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x2*x3*x4,-2 + 4*ep)*tgamma(3*ep) -
> > ? ? ?exp(3*ep*Euler)*pow(ep,-1)*pow(x2,-3*ep)*pow(1 + x3 + x4 + x3*x4,-3*ep)*
> > ? ? ? pow(1 + x2 + x3 + x1*x3 + x2*x3 + x4 + x2*x4 + x3*x4 + x1*x3*x4 + x2*x3*x4,
> > ? ? ? ?-2 + 4*ep)*tgamma(3*ep));
> > ? ??
> > ? ? auto s1 = expr.series(ep,-1);
> > ? ? cout << s1.normal() << endl;
> > ? ??
> > ? ? auto s2 = expr.series(ep,0);
> > ? ? cout << s2.normal() << endl;
> > ? ??
> > ? ? return 0;
> > }
> 
> You did notice that this Laurent series is expanded in ep, not in ep^-1,
> right?
> 
> It might help if you reduce your example program to the bare minimum.
> Then, if you still think it's wrong, please explain what exactly you
> expected instead of the output you got and why.
> 
> All my best,
>   -richy.
> -- 
> Richard B. Kreckel
> <https://in.terlu.de/~kreckel/>
> 
> 
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