UnitStep


Name:
UnitStep - The unit step function (aka Heavyside function)
Synopsis:
 
x UnitStep -> 0 ;if x < 0
-> 1 ;if x >= 0
[x1 x2 ...] UnitStep -> 0 ;if xi < 0 for any xi in [x]
-> 1 ;if xi >= 0 for all xi in [x]

Description:
 
"x UnitStep" represents the unit step function,
equal to 0 for x<0 and 1 for x>=0.

"[x1 x2 ...] UnitStep" represents the multidimensional unit step
function which is 1 only if none of the xi are negative.

Alternatives: Function UnitStep_i for integers, UnitStep_d for
doubles, UnitStep_ia for integer arrays, UnitStep_da for double
arrays (all undocumented) -> behavior and synopsis are the same,
except that no warnings or error messages are thrown.

Diagnostics:
 
When called on an empty array, /ArgumentType is raised.

When first element of the array is not of type integer or double,
/ArgumentType is raised.

Will break if called on an array containing non-numerical values.

Remarks:
 
This is the SLI version of the Mathematica function "UnitStep".
Documentation taken from the Mathematica Book.

Implementation of the type variants can be found in file
synod2/sli/slimath.cc.
References:
 
The Mathematica Book
Author:
Ruediger Kupper  

FirstVersion:
13.3.2003  

SeeAlso: Source:
/home/graber/work-nest/nest-git/nest-simulator/lib/sli/mathematica.sli