People, please let me understand this! Let me give you my example so
that you can help me recognizing where is my mistake
I've this function:
G_igr_d ( <class 'sage.calculus.calculus.SymbolicArithmetic'> )
(2*Iin*rCb/Lf + 2*Vb/Lf)*(s*rCf*(1/(Cf*rCf + Cf*Rs) + s)/((rCf +
Rs)*(s*((1/(Cf*rCf + Cf*Rs) + s)*(2*rCf*rQ/(Lf*rCf + Lf*Rs) +
2*Rs*rQ/(Lf*rCf + Lf*Rs) + rCf*rLf/(Lf*rCf + Lf*Rs) + Rs*rLf/(Lf*rCf +
Lf*Rs) + 2*Iin*rCb*rCf/(Lf*rCf + Lf*Rs) + Rs*rCf/(Lf*rCf + Lf*Rs) +
Rs*2*Iin*rCb/(Lf*rCf + Lf*Rs) + s) + Rs^2/((Cf*rCf + Cf*Rs)*(Lf*rCf +
Lf*Rs))) - (2*Duty/Cb - 1/Cb)*(1/Lf - 2*Duty/Lf)*(1/(Cf*rCf + Cf*Rs) +
s))) + Rs*s/((rCf + Rs)*(Cf*rCf + Cf*Rs)*(s*((1/(Cf*rCf + Cf*Rs) +
s)*(2*rCf*rQ/(Lf*rCf + Lf*Rs) + 2*Rs*rQ/(Lf*rCf + Lf*Rs) +
rCf*rLf/(Lf*rCf + Lf*Rs) + Rs*rLf/(Lf*rCf + Lf*Rs) +
2*Iin*rCb*rCf/(Lf*rCf + Lf*Rs) + Rs*rCf/(Lf*rCf + Lf*Rs) +
Rs*2*Iin*rCb/(Lf*rCf + Lf*Rs) + s) + Rs^2/((Cf*rCf + Cf*Rs)*(Lf*rCf +
Lf*Rs))) - (2*Duty/Cb - 1/Cb)*(1/Lf - 2*Duty/Lf)*(1/(Cf*rCf + Cf*Rs) +
s)))) - 2*ILf*((2*Duty/Lf - 1/Lf)*rCf*(1/(Cf*rCf + Cf*Rs) + s)/((rCf +
Rs)*(s*((1/(Cf*rCf + Cf*Rs) + s)*(2*rCf*rQ/(Lf*rCf + Lf*Rs) +
2*Rs*rQ/(Lf*rCf + Lf*Rs) + rCf*rLf/(Lf*rCf + Lf*Rs) + Rs*rLf/(Lf*rCf +
Lf*Rs) + 2*Iin*rCb*rCf/(Lf*rCf + Lf*Rs) + Rs*rCf/(Lf*rCf + Lf*Rs) +
Rs*2*Iin*rCb/(Lf*rCf + Lf*Rs) + s) + Rs^2/((Cf*rCf + Cf*Rs)*(Lf*rCf +
Lf*Rs))) - (2*Duty/Cb - 1/Cb)*(1/Lf - 2*Duty/Lf)*(1/(Cf*rCf + Cf*Rs) +
s))) - (1/Lf - 2*Duty/Lf)*Rs/((rCf + Rs)*(Cf*rCf + Cf*Rs)*(s*((1/
(Cf*rCf
+ Cf*Rs) + s)*(2*rCf*rQ/(Lf*rCf + Lf*Rs) + 2*Rs*rQ/(Lf*rCf + Lf*Rs) +
rCf*rLf/(Lf*rCf + Lf*Rs) + Rs*rLf/(Lf*rCf + Lf*Rs) +
2*Iin*rCb*rCf/(Lf*rCf + Lf*Rs) + Rs*rCf/(Lf*rCf + Lf*Rs) +
Rs*2*Iin*rCb/(Lf*rCf + Lf*Rs) + s) + Rs^2/((Cf*rCf + Cf*Rs)*(Lf*rCf +
Lf*Rs))) - (2*Duty/Cb - 1/Cb)*(1/Lf - 2*Duty/Lf)*(1/(Cf*rCf + Cf*Rs) +
s))))/Cb
and
params = [
rCf == 1*m_, Cf == 4.7*u_,
rCb == 10*m_, Cb == 22*u_,
rLf == 1*m_, Lf == 1.65*m_,
rQ == 10*m_,
Iin == 300/400,
Rs == 0.2,
Vrms == 220,
Vgr_pk == 220*sqrt(2),
]
paramsd = {
"rCf" : 1*m_, "Cf" :4.7*u_,
"rCb" :10*m_, "Cb" :22*u_,
"rLf" :1*m_, "Lf" :1.65*m_,
"rQ" :10*m_,
"Iin" :300/400,
"Rs" :0.2,
"Vrms" :220,
"Vgr_pk" :220*sqrt(2),
}
NOTE: the m_, u_, etc. are just the multipliers previously defined in
a .sage file (m_ = 1e-3, u_ = 1e-6, etc.)
They are exactly the same subset
If I do
time dizSub = G_igr_d.subs(paramsd)
CPU time: 14.40 s, Wall time: 31.44 s
time G_id = subList(G_igr_d,params)
CPU time: 1.17 s, Wall time: 5.59 s
Why is it so? Please note that this has been done with SAGE : 'SAGE
Version 3.1.2, Release Date: 2008-09-19'
I've tried out this at home (but with simpler expressions) with the
latest SAGE, and the subs with the dictionary actually was faster.
Thank you
Maurizio
On Feb 21, 4:48 pm, Robert Bradshaw <rober...@math.washington.edu>
wrote:
> On Feb 21, 2009, at 3:30 AM, Maurizio wrote:
>
>
>
> > That was the way I used to do it when I discovered the solution_dict
> > param.
>
> > So, I started using the dictionaries to do substitution even in
> > complex expressions... The result was to wait so much time!
>
> > On the contrary, I found that the subs(expr, x=<value>) was SOOOO much
> > faster (are the dictionaries so slow to deal with?).
>
> > So, I implemented a subList function, where I can pass an expression,
> > and a list of substitution, in the very same way that the solve()
> > function returns the results.
>
> > So, now I put all my subsets of numerical values in list like this:
> > set = [x == 10, y == 20, z == 30, ...]
> > and do the substitution like this:
> > result = subList(expr, set)
>
> > Within the function, I just iterate the subs(expr, x = <value>) on the
> > number of list elements.
>
> > This seems to me much faster than using dictionaries, especially for
> > complex expressions.
>
> If this is the case, this is clearly a bug.
>
> - Robert
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