[MATRIX-SIG] -3**(-1/3.), sgn()

[Timothy A. Hochberg]

On Thu, 24 Jul 1997, Jean-Bernard ADDOR wrote:

> I would like to write sgn(a)*abs(a)**(-1/3.) but the sgn function seems
> not to be defined in python (perhaps because it is not in c, but it is in
> fortran). I can use greater_equal. Do you have a better solution ?

For what it's worth, sgn(x) can be implemented as:

def sgn(x):
   return greater_equal(x,0) - less_equal(x,0)

(or is that what you meant by use greater equal?)

 ____   
  /im  

+------------------------------------------------+
|Tim Hochberg            Research Assistant      |
|hochberg <at> wwa.com   University of Illinois  |
|                        Electrical Engineering  |
+------------------------------------------------+


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