Hi Aaron, May the issue due to the fact that the integral that I am trying to perform is 2 dimensional? Maybe Integral() won't work for more than one variable, and therefore evalf() can't evaluate it and leaves it as an expression. Any ideas for solving it? Shall I use another integration function from another library (scipy or numpy)?
El martes, 16 de mayo de 2017, 20:58:53 (UTC+2), Aaron Meurer escribió: > > Looks like a bug. evalf() should work. Can you open an issue for it in > the SymPy issue tracker? > > Aaron Meurer > > On Tue, May 16, 2017 at 2:17 PM, Carlos Bouthelier Madre > <[email protected] <javascript:>> wrote: > > Hi, I am trying to compute an integral of a function f that has no > > primitive, I have used Integral(f,(Tita1, 0, pi/2).(Tita2,0,pi/2)), > because > > I wanted to be able to define it and operate with it before evaluating > it. > > The problem is that when I try to use .evalf(), it won't give me a float > > number, just an expression of the integral divided in several sums of > the > > same integral within different intervals. > > > > The expression of the integral is > > > ZE=16.0*Integral(4*Integral(8.0*(194.818182068005*(-sqrt(0.25*cos(Tita1)**2 > > + 1) + sqrt(0.25*cos(Tita2)**2 + 1))*(sqrt(0.25*cos(Tita1)**2 + 1) + > > sqrt(0.25*cos(Tita2)**2 + 1))*exp(1.5*sqrt(0.25*cos(Tita1)**2 + 1) - > > 0.5*sqrt(0.25*cos(Tita2)**2 + 1)) - > > 194.818182068005*(sqrt(0.25*cos(Tita1)**2 + 1) - sqrt(0.25*cos(Tita2)**2 > + > > 1))**2*exp(0.5*sqrt(0.25*cos(Tita1)**2 + 1) - > 0.5*sqrt(0.25*cos(Tita2)**2 + > > 1)) + 194.818182068005*(sqrt(0.25*cos(Tita1)**2 + 1) - > > sqrt(0.25*cos(Tita2)**2 + 1))**2*exp(1.5*sqrt(0.25*cos(Tita1)**2 + 1) + > > 0.5*sqrt(0.25*cos(Tita2)**2 + 1)) + > > 194.818182068005*(sqrt(0.25*cos(Tita1)**2 + 1) - sqrt(0.25*cos(Tita2)**2 > + > > 1))*(sqrt(0.25*cos(Tita1)**2 + 1) + sqrt(0.25*cos(Tita2)**2 + > > 1))*exp(0.5*sqrt(0.25*cos(Tita1)**2 + 1) + 0.5*sqrt(0.25*cos(Tita2)**2 + > > 1)))*exp(-1.0*sqrt(0.25*cos(Tita1)**2 + 1))/((sqrt(0.25*cos(Tita1)**2 + > 1) - > > sqrt(0.25*cos(Tita2)**2 + 1))**2*(sqrt(0.25*cos(Tita1)**2 + 1) + > > sqrt(0.25*cos(Tita2)**2 + 1))*sqrt(0.25*cos(Tita1)**2 + > > 1)*sqrt(0.25*cos(Tita2)**2 + 1)), (Tita1, 0, 1.5707963267949)), (Tita2, > 0, > > 1.5707963267949)) > > > > What could I use to evaluate it ? How could I define it to make it work? > > > > In fact, I have substituted some other variables in the expression of > ZE, so > > it can compute the Integral. It would also be useful to know how to plot > > ZE(x), if x was the unsubstitude variable inside the previous integral. > > > > > > Thanks in advance > > > > -- > > 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 [email protected] <javascript:>. > > To post to this group, send email to [email protected] > <javascript:>. > > Visit this group at https://groups.google.com/group/sympy. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/sympy/6d80f23d-4e40-4e97-beb4-607e1a72ee43%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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/c3c3e2a5-a4e6-491b-9e90-50bb1bc3dc80%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
