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From: gbastin@x102c.ess.harris.com (Gary Bastin 60293)
Newsgroups: comp.lang.fortran
Subject: Arbitrary Digit Arithmetic
Message-ID: <6005@trantor.harris-atd.com>
Date: 5 Apr 91 15:29:50 GMT
Sender: news@trantor.harris-atd.com
Reply-To: gbastin@x102c.ess.harris.com (Gary Bastin 60293)
Organization: Harris Corporation GSS, Melbourne, Florida
Lines: 21

I am looking for a way to perform arbitrary number rounding,
up to the maximum possible for the data type, for arithmetical
operations.  For example, assume that 4 digit accuracy is desired
and REAL types are used, giving approximately 6 or 7 digits of
accuracy, depending upon the platform.  Then, the problem is to
perform the arithmetic operation, and round the result to 4 digits.
A function ROUND(x,n) could be written for a specific platform,
taking advantage of the internal storage technique used by a
particular compiler, and which would basicly round the mantissa to
n-digits, leaving the exponent unaffected (for n <= the maximum
number of digits possible for the data type).

But, has anyone got any F77 source code for such a function that would be
portable between platforms?

Thanks in advance!

Gary Bastin, WB4YAF      /-/-/      Internet: gbastin@x102c.ess.harris.com
Mail Stop 102-4826         |        phone: (407) 729-3045
Harris Corporation GASD    |        
P.O.B. 94000, Melbourne FL 32902    Speaking from, but not for, Harris!