Command: CyclicValue

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Name:
 CyclicValue - project a cyclic value onto it's norm interval (e.g. angle on [0,360))
Synopsis:
 
  value [b1 b2] CyclicValue -> normvalue
  value  b1 b2  CyclicValue -> normvalue 

  See below for the meaning of b1, b2!
Description:
 
  For a given value and a given norm interval, "CyclicValue" returns
  the value's norm equivalent. This is useful for all values with a
  cyclic definition, such as angles.  
  The output is always of type double, regardless of the input type.

  Alternatives: Function CyclicValue_d_d_d if you use it with three doubles
  (interval = double1 - double2), CyclicValue_d_a if you use it with
  double and array (both undocumented) -> behaviour and synopsis are the same.
Parameters:
 
  In :  value:   value in (-oo, oo)

        b1, b2:  norm interval.
                 This interval is half-open: [.), or (.], depending on
                 the following rules:

                 b1 must not equal b2.                   
                 b1 always denotes the closed end of the interval.
                 b2 always denotes the open   end of the interval.                 
                 If b1b2, the norm interval used is (b2,b1].

                 See below for examples.  
        
  Out:  The value's norm equivalent in the interval [b1, b2).
        The output is always of type double, regardless of the input
        type.
Diagnostics:
    b1 must not equal b2. This is not checked for efficency reasons!
    If b1=b2, code will break with /DivisionByZero during execution.
Examples:
  %% project angle in degrees onto [0,360):
  -3601 [0 360] CyclicValue -> 359.0

  %% project angle in radians onto [-pi,pi):
  23.0 [Pi -1 mul  Pi] CyclicValue -> -2.13274

  %% this demonstrates the handling of open/closed interval ends:
  %%   project number onto [1,4):
  1 [1 4] CyclicValue -> 1
  2 [1 4] CyclicValue -> 2
  3 [1 4] CyclicValue -> 3   
  4 [1 4] CyclicValue -> 1   
  %%   project number onto (1,4]:
  1 [4 1] CyclicValue -> 4
  2 [4 1] CyclicValue -> 2
  3 [4 1] CyclicValue -> 3   
  4 [4 1] CyclicValue -> 4
Author:
 Ruediger Kupper
FirstVersion:
 13.3.2003
Remarks:
  Variant *_d_d_d is fastest. Prefer this variant over *_d_a in time
  critical applications.    

  Inspired by IDL/NASE commandfunction cyclic_value().
SeeAlso:mod floor
Source:
 /home/abuild/rpmbuild/BUILD/nest-2.4.1/lib/sli/misc_helpers.sli

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