# Command: unittest::ToUnitTestPrecision

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Name:

    unittest::ToUnitTestPrecision - reduce argument to specified precision.

Synopsis:

      double integer ToUnitTestPrecision -> double or integer
      array  integer ToUnitTestPrecision -> array
      other  integer ToUnitTestPrecision -> other

Examples:

      7.83635342928 6 ToUnitTestPrecision  -->   7.83635
      -32.38763534   6 ToUnitTestPrecision  -->  -32.3876
      (flower)  6 ToUnitTestPrecision  -->   (flower)
      [7.83635342928 (flower) -32.38763534]
      6 ToUnitTestPrecision   --> [7.83635 (flower) -32.3876]
      -70	 6 ToUnitTestPrecision type --> /integertype
      -70.0	 6 ToUnitTestPrecision type --> /integertype

Description:

      Reduces its double argument to the precision specified by the integer.
      If the first argument is an array, ToUnitTestPrecision is recursively
      applied to all elements of the array. Any other first argument is
      returned unchanged. This is useful in processing heterogeneous arrays.
      ToUnitTestPrecision uses a C++ output stream to carry out the reduction
      of precision and  manipulator setprecision() is used to set the precision.
      The contents of the stream is converted back to a numerical object by
      operator token. This guarantees that for the conversion from text to double
      the same algorithm
      is used for the argument of  ToUnitTestPrecision and the reference data,
      usually explicitly specified in the test file as an array.
      The double argument may contain an integral value or be converted to and
      integral value due to the required precision. In this case the output
      operator of the stream may decide to represent the value as an integer,
      i. e. without a decimal point, trailing zeros, or an exponent. This often
      increases the readability of reference data arrays (see e.g. test_iaf). The
      SLI interpreter function then returns an object of type integer.
      The operators token and cvd use the same algorithm for converting text to
      to a numerical value. However cvd always return a double.
      ToUnitTestPrecision is not an efficient algorithm for rounding numerical
      values. The idea rather is to have an algorithm which is guaranteed to be
      compatible with the text stream output of a simulation.

Author:

    Markus Diesmann

FirstVersion:

    071108

SeeAlso:

- unittest::assert_or_die
- token
- cvd
- testsuite::test_iaf

Source:

    /opt/conda/conda-bld/nest_1524088722951/work/nest-2.14.0/lib/sli/unittest.sli

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