Message Boards Message Boards

2 Replies
0 Total Likes
View groups...
Share this post:

How to force Mathematica (NIntegrate) to output real values

Posted 11 years ago
Here's the issue. I have a function that  yields a value for NIntegrate of a Real and an Imaginary term of comperable sizes. If Mathematica treats all values internally as complex values, then I need to limit the branch used in the integration to only the one that yields a real value and no imaginary component.

The integrand is alway greater than zero, so there is no obvious pole, yet the complex output persists. I am not sure what assumptions or requirements will force the answer to always be real.

Thanks for any explanation of what is going on and how to get the real value I am looking for.

POSTED BY: Luther Nayhm
2 Replies
You say that the real and imaginary parts are of comparable size.  Are they both close to 0 in magnitude?
In that case the integral is probably 0.
POSTED BY: Frank Kampas
Posted 11 years ago
That was my thought, also, but it is more complicated that that. The actual value should be small but the integrand is definitely not zero anywhere.

I will force the size of the integrand to be both larger and farther from zero, which exceeds the scenario I am interested in but will help nail down the origin of the issue.
POSTED BY: Luther Nayhm
Reply to this discussion
Community posts can be styled and formatted using the Markdown syntax.
Reply Preview
or Discard

Group Abstract Group Abstract