[SciPy-user] do complex numbers default to double precision?

Gary pajer at iname.com
Thu Jun 30 07:00:02 CDT 2005


Ryan Krauss wrote:

> I have a matrix that is a function of a complex valued input.  I am 
> trying to find that value of that input that drives the determinant of 
> the matrix to zero.  I am searching for this value using fmin. The 
> error I am trying to minimize is the abs(det(complex matrix)).  I 
> don't seem to be able to drive this error lower that roughly 9e-17, 
> regardless of the values for ftol and xtol I use.
>
Many years ago I did some programing in "pure" Forth, which does not 
support floating point numbers.  That's right: integers only.  I learned 
something about the limitations of floating point numbers, and something 
else about restructuring problems.  I'm not suggesting you switch to 
integer arithmetic.  Your question just rang a bell in my head.  Maybe 
there is some other way to formulate your problem so that you don't run 
up against floating point limitations.  Who hasn't gotten bitten by 
blind reliance on floating point arithmetic?

just a thought,
gary


> Am I hitting some internal limitation?  Are complex values by default 
> single or double precision?
>
> Thanks,
>
> Ryan
>



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