EXP2 3CW "09 March 2006" "mathcw-1.00"

Table of contents


NAME

exp2f, exp2, exp2l, exp2w, exp2q, exp2ll, exp2df, exp2d, exp2dl, exp2dll - exponential base-2 function

SYNOPSIS

cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ]

#include <mathcw.h>

extern float exp2f (float x);

extern double exp2 (double x);

extern long double exp2l (long double x);

extern __float80 exp2w (__float80 x);

extern __float128 exp2q (__float128 x);

extern long_long_double exp2ll (long_long_double x);

extern decimal_float exp2df (decimal_float x);

extern decimal_double exp2d (decimal_double x);

extern decimal_long_double exp2dl (decimal_long_double x);

extern decimal_long_long_double exp2dll (decimal_long_long_double x);

NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.


DESCRIPTION

Compute the base-2 exponential of x, that is, 2 to the power x.

This function is likely to be more accurate than the mathematically-equivalent expression using the power function, such as pow(2.0, x).

Caution: Because the function grows rapidly for arguments of large magnitude, it approaches Infinity fairly quickly. Also, for arguments of small magnitude, exp2(x) - 1 suffers loss of leading significant digits; use the accurate exp2m1(x) function instead.


RETURN VALUES

Return the base-2 exponential of the argument, or a NaN if the argument is a NaN.

ERRORS

If the argument is a NaN, return the argument, and set errno to EDOM. If the argument is large enough that the function value is too large to represent (i.e., it overflows), return Infinity, and set errno to ERANGE.

SEE ALSO

exp(3CW), expm1(3CW), exp2m1(3CW), exp8(3CW), exp8m1(3CW), exp10(3CW), exp10m1(3CW), exp16(3CW), exp16m1(3CW), log(3CW), log1p(3CW), log2(3CW), log21p(3CW), log8(3CW), log81p(3CW), log10(3CW), log101p(3CW), log16(3CW), log161p(3CW).