From bug-octave-request at bevo dot che dot wisc dot edu  Mon Jul 12 22:51:45 1999
Subject: Min and max fail for NaN values
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: olli dot saarela at kcl dot fi
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Mon, 12 Jul 1999 22:51:29 -0500 (CDT)

On 12-Jul-1999, Olli Saarela <olli dot saarela at kcl dot fi> wrote:

| In Octave 2.0.13, the min and max functions fail for NaN values:
| 
|   >> [min(0,NaN) min(NaN,0) max(0,NaN) max(NaN,0)]
|   ans =  NaN    0  NaN    0
| 
| but the result should be
| 
|   ans =  NaN  NaN  NaN  NaN
| 
| 
| minmax.cc (same source in 2.0.14 and 2.1.14) uses a definition like
| 
|   #ifndef MAX
|   #define MAX(a,b) ((a) > (b) ? (a) : (b))
|   #endif
|   #ifndef MIN
|   ...
| 
| This should be replaced by something like
| 
|   #undef MAX
|   static inline double MAX(double a, double b) {
|      if (a > b) {
|         return a;
|      } else {
|         if (isnan(a))
|            return a;
|         return b;
|      }
|   }
|   #undef MIN
|   ...
| 
| Similar comparisons should be used throughout at least that file.

I've fixed this problem in my sources for 2.1.x, but I used a slightly
different approach.

Thanks,

jwe



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