I think what I have done is correct up to the point of taking the convolution product.  Both G(t) and H(t) are piecewise functions. You have to be super careful when convolving them.  I think that is where I messed up.  I am working on a sympy class to convolve piecewise functions.  Currently it works for some but I hard coded some things in the class I shouldn't have and am currently fixing that problem.

 On 2/8/23 4:24 AM, 'Tom van Woudenberg' via sympy wrote:
Hi Brombo,

Thank you for the extensive working-out. I really appreciate that!
However, the result doesn't seem to match the result in got in Maple (below result in Python for N(t):

Schermafbeelding 2023-02-08 094041.jpg
Do you have any ideas on the difference?
Op woensdag 8 februari 2023 om 01:10:05 UTC+1 schreef brombo:

    I didn't proof read well enough.  Typo in equation 4. Correction
    attached

    On 2/7/23 3:02 AM, 'Tom van Woudenberg' via sympy wrote:
    Thank you brombo, I'll take a closer look at the file you send me!

    Op maandag 6 februari 2023 om 22:29:25 UTC+1 schreef brombo:

        I cleaned things up here is what the notebook looks like (see
        attached html) -


        On 2/6/23 10:36 AM, 'Tom van Woudenberg' via sympy wrote:
        Hi there,

        When trying to solve a integral as part of a manual inverse
        fourier transform, SymPy return the unevaluated integral.
        Does anybody know if SymPy is able to solve this integral
        with some help? It would be good enough if I'd be able to
        obtain the result for specific values of t.

        import sympy as sp
        phi,t = sp.symbols('phi,t',real=True)
        sp.I*(1 -
        
sp.exp(4*sp.I*sp.pi*phi))*sp.exp(-8*sp.I*sp.pi*phi)/(2*sp.pi*phi*(-4*sp.pi**2*phi**2
        + 1.5*sp.I*sp.pi*phi + 4))
        solution_numeric = 1 / sp.pi * sp.integrate(sp.re
        
<http://sp.re>(solution_in_frequency_domain_numeric*sp.exp(sp.I*2*phi*t)),(phi,0,4))
        print(solution_numeric)

        returns:
        
(Integral(sin(4*pi*phi)*re(exp(2*I*phi*t)/(-4*pi**2*phi**2*exp(8*I*pi*phi)
        + 1.5*I*pi*phi*exp(8*I*pi*phi) + 4*exp(8*I*pi*phi))), (phi,
        0, 4)) +
        
Integral(cos(4*pi*phi)*im(exp(2*I*phi*t)/(-4*pi**2*phi**2*exp(8*I*pi*phi)
        + 1.5*I*pi*phi*exp(8*I*pi*phi) + 4*exp(8*I*pi*phi))), (phi,
        0, 4)) +
        Integral(-im(exp(2*I*phi*t)/(-4*pi**2*phi**2*exp(8*I*pi*phi)
        + 1.5*I*pi*phi*exp(8*I*pi*phi) + 4*exp(8*I*pi*phi))), (phi,
        0, 4)))/(2*pi**2*phi)

        Plotting the result for t,0,15 should give this result
        according to Maple:
        Schermafbeelding 2023-02-06 163521.jpg

        Kind regards,
        Tom van Woudenberg
        Delft University of Technology
-- You received this message because you are subscribed to the
        Google Groups "sympy" group.
        To unsubscribe from this group and stop receiving emails
        from it, send an email to sympy+un...@googlegroups.com.
        To view this discussion on the web visit
        
https://groups.google.com/d/msgid/sympy/eea7eaef-8752-41f8-bf9d-ba78a1782c37n%40googlegroups.com
        
<https://groups.google.com/d/msgid/sympy/eea7eaef-8752-41f8-bf9d-ba78a1782c37n%40googlegroups.com?utm_medium=email&utm_source=footer>.

-- You received this message because you are subscribed to the
    Google Groups "sympy" group.
    To unsubscribe from this group and stop receiving emails from it,
    send an email to sympy+un...@googlegroups.com.
    To view this discussion on the web visit
    
https://groups.google.com/d/msgid/sympy/e27ffb73-aad8-4bb1-a004-fbe0a27b9074n%40googlegroups.com
    
<https://groups.google.com/d/msgid/sympy/e27ffb73-aad8-4bb1-a004-fbe0a27b9074n%40googlegroups.com?utm_medium=email&utm_source=footer>.

--
You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/723c7d86-1c6d-492a-9f86-16978b4b837bn%40googlegroups.com <https://groups.google.com/d/msgid/sympy/723c7d86-1c6d-492a-9f86-16978b4b837bn%40googlegroups.com?utm_medium=email&utm_source=footer>.

--
You received this message because you are subscribed to the Google Groups 
"sympy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sympy+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/sympy/fc3e1fb3-bceb-efef-cfdb-d5190df88307%40gmail.com.

Reply via email to