Name: UnitStep - The unit step function (aka Heavyside function)

Synopsis:

x  UnitStep -&gt; 0   ;if  x &lt;  0 
-&gt; 1   ;if  x &gt;= 0 
[x1 x2 ...] UnitStep -&gt; 0   ;if xi &lt;  0 for any xi in [x] 
-&gt; 1   ;if xi &gt;= 0 for all xi in [x]


Description:

"x UnitStep" represents the unit step function, 
equal to 0 for x&lt;0 and 1 for x&gt;=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) -&gt; 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:

Sign
abs

Source:

/var/www/debian/nest/nest-simulator-2.20.0/lib/sli/mathematica.sli
