Timeline for Compute integral symbolically or numerically
Current License: CC BY-SA 3.0
15 events
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| Feb 28, 2012 at 13:24 | vote | accept | CommunityBot | moved from User.Id=207 by developer User.Id=86366 | |
| Feb 27, 2012 at 15:54 | answer | added | Daniel Lichtblau | timeline score: 4 | |
| Feb 27, 2012 at 15:03 | history | edited | Jonas T | CC BY-SA 3.0 |
Added integration method
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| Feb 26, 2012 at 22:27 | history | edited | Jonas T | CC BY-SA 3.0 |
added 564 characters in body
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| Feb 26, 2012 at 21:51 | history | edited | Jonas T | CC BY-SA 3.0 |
Something about the coefficients
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| Feb 26, 2012 at 21:09 | answer | added | acl | timeline score: 3 | |
| Feb 26, 2012 at 20:57 | comment | added | Jonas T | @acl It shouldn't vanish, it can be really small though. It denotes the electric field of a laser. | |
| Feb 26, 2012 at 20:56 | comment | added | acl | Wait are you sure this does not vanish? | |
| Feb 26, 2012 at 20:54 | comment | added | acl |
OK, I see. No, I have the same problem that you report, and I don't see why. I tried Plot3D[Im[withTransforms[intgnd]],{a, 0, Pi/4},{b, 0, 2*Pi}] (here intgnd is the first expression in your question), and see no problem (also, no problem is evident with its real part).
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| Feb 26, 2012 at 20:43 | comment | added | Jonas T | @acl: $k$ is $2 \pi$. I have added this now. Does the integration work for you? | |
| Feb 26, 2012 at 20:42 | history | edited | Jonas T | CC BY-SA 3.0 |
added 20 characters in body
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| Feb 26, 2012 at 20:39 | comment | added | acl |
maybe I am just missing it, but I don't see what k is supposed to be (I changed NIntegrate to nintegrate to see what would the integrand would be, and a k is left in there). I also tried setting k=1 and plotting the real and imaginary parts of the integrand and see no obvious problems; but perhaps I am looking at the wrong integrand.
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| Feb 26, 2012 at 19:15 | comment | added | Jonas T |
@RM Thanks! At least for some integrands, that helps (I don't get that error anymore) but still Mathematica takes a very long time (at this moment it didn't finish yet) to compute that integral. If I use your modification on IntoN it gives for the same integrand the same result for the unmodified IntoS. I'm not sure what you mean with "change your answer".
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| Feb 26, 2012 at 19:03 | comment | added | rm -rf♦ |
I haven't tried your code, but it seems like you meant to evaluate withTransforms[int] before passing to (N)Integrate... otherwise, it doesn't make sense to call that on the output of NIntegrate, which is just a number. It could possibly change how your integral behaves, but certainly will change your answer.
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| Feb 26, 2012 at 18:23 | history | asked | Jonas T | CC BY-SA 3.0 |