Working with NAN

[Dimster]

Thanks for this Steve. INF I think I have a working solution. NaN's been escaping me. I'm not sure if others who may be following this thread might find your treatment of INF handy.

[SMcNeill]

Thanks for this Steve. INF I think I have a working solution. NaN's been escaping me. I'm not sure if others who may be following this thread might find your treatment of INF handy.

Glad to be of service.  

[SMcNeill]

@Dimster You might want to double check my code there.

DECLARE CUSTOMTYPE LIBRARY "isnan"
FUNCTION IsNan% (BYVAL n AS DOUBLE)
END DECLARE

I'm kinda surprised that worked before. We should be passing values BYVAL, and I left that out above. I just had my gallbladder removed yesterday and I'm still on some NICE pain meds for the next few days as I heal up. My brain is probably at 50% capacity so double check anything I say for now. LOL,

[SMcNeill]

Try this as a properly working version:

Save as isnan.h:

Code: (Select All)

#include <stdio.h>
#include <math.h>
#include <float.h>

int IsNan (long double n);
int IsInf (long double n);

IsNan (long double n) { return -isnan(n); }
IsInf (long double n) { return -isinf(n); }

And the test code to check for NaN and Inf:

Code: (Select All)

DECLARE LIBRARY "isnan"

    FUNCTION IsNan% (BYVAL n AS _FLOAT)

    FUNCTION IsInf% (BYVAL n AS _FLOAT)

END DECLARE



PRINT IsNan(0 / 0), IsInf(0 / 0)

PRINT IsInf(1 / 0), IsInf(1 / 0)

PRINT IsInf(0 / 1), IsInf(0 / 1)

Notice the output is:
0 / 0 is NaN but is *not* INF.
1 / 0 is NaN and is also INF.
0 / 1 is neither NaN, nor is it INF.

[grymmjack]

@smcneill this should go on wiki.

Glad your surgery was a success and healing up.

[eoredson]

In SICK it is:

Code: (Select All)

5 Rem Qnan.sic
10 Print "-1// equals: ";
20 Print Suffix(-1//) '  as  -1.#IND  (cannot be calculated/NAN - not a number)
30 Print "-(-1//) equals: ";
40 Print Suffix(-(-1//)) '  as  1.#QNAN (results as a quotient not a number)
50 Print "1/0 equals: ";
60 Print Suffix(1/0)  '  as  1.#INF  (underflow) (division by zero)
70 Print "-(1/0) equals: ";
80 Print Suffix(-(1/0)) '  as  -1.#INF  (negative underflow) (division by zero)