So perhaps you would have better results if you started with a Float
with higher precision, like Float("0.07071", 100).Aaron Meurer On Sun, Feb 8, 2015 at 2:57 PM, Kalevi Suominen <jks...@gmail.com> wrote: > > > On Sunday, February 8, 2015 at 12:06:46 AM UTC+2, Sten Sogaard wrote >> >> >> H = 1/(0.07071*s**2 + 258.0*s + 1100000.) >> inverse_laplace_transform(1/s*H,s,t) >> >> >> Any ideas? > > > The current implementation leads to floating point numbers with very large > positive and negative exponents. After the small numbers are rounded to > zero, nan results. > > However, the computation succeeds with suitably normalized coefficients: > ``` > In [38]: H1 = H.subs(s, 10000.*s) > In [40]: print(inverse_laplace_transform(1/s*H1, s, t)) > -1.0*(-9.09090909090909e-7*exp(0.182435299109037*t) + > 4.74279450417556e-7*sin(0.349688926583877*t) + > 9.09090909090909e-7*cos(0.349688926583877*t))*exp(-0.182435299109037*t)*Heaviside(t) > ``` > (Of course, the result has to be normalized again.) > > For a more satisfactory solution, cancellation of exponents in the > intermediate results would be required. > > -- > 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 post to this group, send email to sympy@googlegroups.com. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/83a765a9-c984-4fa2-bbc2-00010e02ed83%40googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. -- 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 post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2B9bNhRYhBv83VKwKcOinkfSdv6DZ9JgBR3gTrhLTjByw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
