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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