On Oct 23, 8:05 am, "William Stein" <[EMAIL PROTECTED]> wrote:
> On Thu, Oct 23, 2008 at 7:56 AM, John H Palmieri <[EMAIL PROTECTED]> wrote:
>
> > The setup:
>
> > sage: var('x y')
> > sage: F = sin(x^2 + y^2) * cos(y) * exp(-0.5*(x^2+y^2))
> > sage: G=F.derivative(x,x); G
> > -3.00000000000000*x^2*e^(-(0.500000000000000*(y^2 +
> > x^2)))*cos(y)*sin(y^2 + x^2) -
> > 1.00000000000000*e^(-(0.500000000000000*(y^2 + x^2)))*cos(y)*sin(y^2 +
> > x^2) - 4.00000000000000*x^2*e^(-(0.500000000000000*(y^2 +
> > x^2)))*cos(y)*cos(y^2 + x^2) + 2*e^(-(0.500000000000000*(y^2 +
> > x^2)))*cos(y)*cos(y^2 + x^2)
>
> > Then the following takes a long time, between 5 and 10 seconds on my
> > 2.4 GHz Intel iMac.
>
> > sage: G(1.2, 1.2)
> > 0.193703001636676
>
> > (I tried using 'timeit(G(1.2, 1.2))' but got: AttributeError:
> > 'SymbolicArithmetic' object has no attribute 'find'.)
>
> > Why is it so slow, and are there any tricks I can use to speed it up?
>
> Because (the way Sage uses!?) Maxima sucks.
>
> For two months now several of us have been working on completely
> replacing Sage's use of Maxima for symbolic manipulation with reliance
> on a C++ library called Ginac. This will make its first appearance as
> a non-default option in Sage-3.2.
>
> William
My impression is that Ginac is in 3.2-alpha0, which I just installed.
Can I use it to do these computations? If so, how?
John
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