I'm guessing that the issue is that your integrand simplifies when q=1 --
at least one term becomes zero -- but you do the integral before doing this
simplification. Maybe the symbolic integration is not valid when q=1. If
you plug in the parameters before integrating, you get something very
different from Sage. Adding these two lines
qs=integral(((TVcoff(t))^2/moff).subs(**params),t, d*pi/omega, 2*pi/omega)
# substitute before integrating
Nqs = qs.subs(**params).n()
gives me something close to Maple's answer:
sage: Nps
1057.74513808638 + 3.42074504083530*I
sage: Nqs
0.0164729319512844 + 5.58793544769287e-9*I
John
On Tuesday, April 15, 2014 9:14:39 PM UTC-7, jorges wrote:
>
> Hi,
> Some time ago I translated the derivation of a problem from MAPLE to SAGE.
> It took some time but I got it all working, until last week I found some
> strange results for a specific value of one of the parameters. Basically
> MAPLE and SAGE agree on all but one of the values I tried for parameter
> 'q'. The problem arises for 'q'=1 (See the minimal example below). I tend
> to trust MAPLE's result, given the meaning of the integral, a normalized
> form of the power dissipated at a switch when it is off, i.e V^2/R
> Any clues of what might be going on here?
>
> This is with SAGE 6.1.1, on Arch linux 64 bits
>
>
> # Note that d, q, mon, moff, Vdd and omega are independent INPUT
> parameters, and that the rest are dependent intermediate results
> var('d p q phi mon moff Vdd Coff1 Coff2 omega')
> params = {'phi': -0.342466921443868, 'd': 1, 'p': 3.69012461123172, 'q':
> 1.0, 'Vdd': 1, 'Coff2': 621.040280393254 - 1743.07649791142*I, 'moff':
> 1000, 'Coff1': 621.040280393254 + 1743.07649791141*I, 'omega': 1, 'mon':
> 0.01}
> aoff =(1/2)*(-1+sqrt(1-4*q^2*moff^2))/moff
> boff = -(1/2)*(1+sqrt(1-4*q^2*moff^2))/moff
>
> TVcoff(t)=Coff1*exp(aoff*omega*t)+Coff2*exp(boff*omega*t)+Vdd+Vdd*(p*q^2*moff^2*(q-1)*(q+1)*cos(omega*t+phi)+p*sin(omega*t+phi)*moff*q^2)/(1+(q^4-2*q^2+1)*moff^2);
> ps=integral(((TVcoff(t))^2/moff),t, d*pi/omega, 2*pi/omega)
> Nps = ps.subs(**params).n()
> # The value I am interested in is the real part of Nps
> print Nps
>
> -1083.52083510533 + 4.70489703060889*I
>
> MAPLE returns
>
> 0.168006953631138e-1-0.615350612025753e-19*I
>
>
>
> jorge
>
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