math.frexp - what's it mean?
tim.one at home.com
Thu Sep 13 01:22:35 CEST 2001
> Not being a numeric type person, "frexp" conjured up absolutely
> no mnemonic significance for me. The library reference manual was no
> help either. Finally, I tried "man frexp" and got "convert floating-
> point number to fractional and integral components".
That's a particularly lame man page -- I'd only say that of modf(), which
actually does break a float into fractional and integral components (like
math.modf(7.25) == (0.25, 7.0)).
> Now I know what it means mnemonically ("FRaction EXPonent", I guess),
> but the name is still perplexing.
Good for you, Skip! I never had any idea what it meant, and never thought
to wonder. When I was learning C and Unix, it was just another senseless
string to memorize ('cat' to copy a file to stdout, 'ls' to display a
directory, 'frexp' to break up a float, 'ldexp' to multiply by a power of 2,
... all the same to me at the time).
> Why not "manexp"?
Why 'modf'? OS people can't even name OS functions sensibly; they're
hopeless when it comes to libm functions <wink>.
> Does its use predate its appearance in C?
AFAIK the name 'frexp' originated there.
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