Re: [sage-support] Solving differential equations with unit_step?

Great. Ask on the sympy list if you have any problems. He's also got a branch https://github.com/sympy/sympy/pull/543 that should improve the integration capabilities of SymPy even more (esp. for definite integrals). It should be merged pretty soon. Aaron Meurer On Jan 9, 2:01 pm, Renan Birck P

Re: [sympy] Re: [sage-support] Solving differential equations with unit_step?

2012/1/9 Aaron Meurer > Thanks to Tom's Google Summer of Code project, SymPy can indeed solve > this problem. The code is only in the git master, but will be included > in SymPy 0.7.2. > This looks pretty good, I will try and compile the git version. Thanks. -- Renan Birck Pinheiro, Grupo de M

Re: [sympy] Re: [sage-support] Solving differential equations with unit_step?

And I should note that Tom's code can also compute the Laplace transform if you want to do it that way: In [13]: var('s') Out[13]: s In [14]: inverse_laplace_transform(exp(-5*s)/s, s, t) Out[14]: Heaviside(t - 5) Aaron Meurer On Mon, Jan 9, 2012 at 1:36 PM, Aaron Meurer wrote: > Thanks to Tom'

Re: [sympy] Re: [sage-support] Solving differential equations with unit_step?

Thanks to Tom's Google Summer of Code project, SymPy can indeed solve this problem. The code is only in the git master, but will be included in SymPy 0.7.2. In [3]: dsolve(Derivative(y(x),x) - Heaviside(-5 + x), y(x)) Out[3]: ⎧ │x│ y(x) = C₁ + 5⋅⎪

Re: [sage-support] Solving differential equations with unit_step?

2012/1/9 David Joyner > AFAIK, Sage cannot at this time take the inverse Laplace transform of > something of the form e^{-5s}/s. > > And indeed it can't. sage: F = e^(-5*s)/s sage: F.inverse_laplace(s,t) ilt(e^(-5*s)/s, s, t) -- Renan Birck Pinheiro, Grupo de Microeletrônica

Re: [sage-support] Solving differential equations with unit_step?

AFAIK, Sage cannot at this time take the inverse Laplace transform of something of the form e^{-5s}/s. I think Sympy (included with Sage) can http://docs.sympy.org/dev/modules/integrals/integrals.html#integral-transforms but I don't think it's been integrated together with initial conditions: >>>

[sage-support] Solving differential equations with unit_step?

Hi, I'm trying to solve a differential equation with unit step, e.g. the equation y'(x) = U(x-5) - where U is the unit step, and the inicial condition y(0) is 0. The result is 0 for 05 (it's a simple integral of the unit step function). WolframAlpha gives the correct result [1], however sage fail