# Command: UnitStep

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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:

- Sign
- abs

Source:

    /opt/conda/conda-bld/nest_1512418773968/work/nest-2.14.0/lib/sli/mathematica.sli

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