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Branch cut for sqrt

Posted 2017/12/10 9:23 GMT-5 Low-Frequency Electromagnetics, Parameters, Variables, & Functions Version 5.3 0 Replies

John
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Hi,

For EM modelling, I need result of sqrt to always have positive imaginary part.

My version of Comsol sqrt appears to take a branch cut on -ve axis (e.g. sqrt(-2+0.001i) = 3.e-4+1.4i whereas sqrt(-2-0.001i) = 3.e-4 -1.4i, can I assume that will always be the case in future versions?

Assuming so, then it should be safe to define csqrt( z ) = i * sqrt( - z)

Is such a function already defined and/or are there simpler ways to do this?

Thanks, John

0 Replies Last Post 2017/12/10 9:23 GMT-5
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