FIX: Incorrect Results with PARAMETER in NINT
ID: Q77341
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5.00 5.10 | 5.00 5.10
MS-DOS | OS/2
kbprg kbfixlist kbbuglist
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The information in this article applies to:
- Microsoft FORTRAN for MS-DOS, versions 5.0 and 5.1
- Microsoft FORTRAN for OS/2, versions 5.0 and 5.1
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SYMPTOMS
========
Programs that contain a PARAMETER constant in an arithmatic expression
within the NINT intrinsic function argument list may generate incorrect
results during run time.
RESOLUTION
==========
One way to work around this problem is to use a variable in the expression
instead of a PARAMETER.
STATUS
======
Microsoft has confirmed this to be a problem in the products listed above.
This problem was corrected in FORTRAN PowerStation.
MORE INFORMATION
================
The following code can be sued to reproduce the problem:
Sample code
-----------
integer*4 iconst
parameter (iconst = 1024)
real sdata, ddata
ddata = 200.0
sdata = 0.001
c iconst = 1024
c incorrect results generated here
print *, 'NINT(ddata * iconst * sdata) * 2 = ',
* NINT(ddata * iconst * sdata) * 2
print *, 'NINT(ddata * iconst * 0.001) * 2 = ',
* NINT(ddata * iconst * 0.001) * 2
print *, 'NINT(200.0 * iconst * sdata) * 2 = ',
* NINT(200.0 * iconst * sdata) * 2
print *, 'NINT(200.0 * iconst * 0.001) * 2 = ',
* NINT(200.0 * iconst * 0.001) * 2
print *, 'NINT(ddata * iconst * sdata) + 2 = ',
* NINT(ddata * iconst * sdata) + 2
print *, 'NINT(ddata * iconst * 0.001) + 2 = ',
* NINT(ddata * iconst * 0.001) + 2
END
Output:
NINT(ddata * iconst * sdata) * 2 = 409 ! this value should be 410
NINT(ddata * iconst * 0.001) * 2 = 410
NINT(200.0 * iconst * sdata) * 2 = 410
NINT(200.0 * iconst * 0.001) * 2 = 410
NINT(ddata * iconst * sdata) + 2 = 207
NINT(ddata * iconst * 0.001) + 2 = 207
Additional reference words: 5.00 5.10 buglist5.00 buglist5.10 fixlist1.00
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KBSubCategory: FORTLngIss
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Last Reviewed: January 25, 1995