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Q149506: BUG: /4fps1 and /Ox Compiler Options with Complex Calculations

Article: Q149506
Product(s): Microsoft Fortran Compiler
Version(s): 4.0
Operating System(s): 
Keyword(s): kbFortranPS kbLangFortrankbbuglist
Last Modified: 03-NOV-1999

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The information in this article applies to:

- Microsoft Fortran PowerStation for Windows 95 and Windows NT, version 4.0 
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SYMPTOMS
========

Using the /4fps1 and /Ox compiler options together with source code containing
complex number calculations causes the results of those calculations to be
erroneous.

RESOLUTION
==========

If you are performing complex number calculations, do not use the /4fps1 and /Ox
compiler options together.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

Sample Code to Illustrate Problem
---------------------------------

  C Compile options needed: none

        COMPLEX A, B

        C = 3.1415926535897932384626434
        D = 3.0/2.0

        B = CMPLX(COS(1.5), SIN(D)) ** 3
        WRITE(*,*) B

        A = B - CMPLX(COS(4.5), -SIN(4.5 + C))
        WRITE(*,*) A

        END

Correct Output
--------------

  (-2.107958E-01,-9.775301E-01)
  (9.473733E-09,0.000000E+00)

Output using /4fps1 /Ox
-----------------------

  (-3.537882E-05,6.484614E-05)
  (2.107604E-01,9.775950E-01)

Additional query words: 4.00

======================================================================
Keywords          : kbFortranPS kbLangFortran kbbuglist
Technology        : kbAudDeveloper kbPTProdChange kbFortranSearch kbFORTRANPower400NT
Version           : :4.0

=============================================================================

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