exp

Date:

10-12-2011

NAME

EXP, DEXP, CEXP, CDEXP - Compute exponential function

SYNOPSIS

EXP ([X=]x)
DEXP ([X=]x)
CEXP ([X=]x)
CDEXP ([X=]x)

IMPLEMENTATION

Cray Linux Environment (CLE)

STANDARDS

Fortran

Fortran extension: CDEXP

DESCRIPTION

EXP is the generic function name; the others are specifics. These are elemental intrinsic functions that accept the following argument:

x

Must be of type real (for EXP and DEXP) or complex (for CEXP and CDEXP). The type and kind type of x is identical to the type and kind type of the return value. See the NOTES section for the range of values these intrinsics can accept. See the RETURN VALUES section for information on input data types and return values.

Vector versions of the EXP, DEXP, CEXP, and CDEXP intrinsic functions exist.

These functions evaluate this equation y = ex.

NOTES

The EXP, DEXP, and CEXP intrinsic function names can be passed as arguments; the others cannot.

The range of values that any exponential intrinsic documented in this man page can accept is determined by the size of the data type (that is, REAL or the real portion of a COMPLEX variable):

REAL(KIND=4)

-87.3 < x < 88.7

  • EXP(x) returns 0.0 if x is less than -87.3 (approximately)

  • EXP(x) returns infinity if x is greater than 88.7 (approximately)

REAL(KIND=8)

-708.4 < x < 709.78

  • EXP(x) returns 0.0 if x is less than -708.4 (approximately)

  • EXP(x) returns infinity if x is greater than 709.78 (approximately)

REAL(KIND=16)

-11,355 < x < 11,356

  • EXP(x) returns 0.0 if x is less than -11,355(approximately)

  • EXP(x) returns infinity if x is greater than 11,356 (approximately)

Note: The exp() and cexp() functions have Linux-equivalent names. Use the man -aname option to show all manual pages matching name within the MANPATH search path. Manual pages are displayed in the order found.

RETURN VALUES

EXP(NaN) yields NaN.

EXP returns the single-precision real exponential function of its real argument.

DEXP returns the double-precision real exponential function of its double-precision real argument.

CEXP returns the single-precision complex exponential function of its single-precision complex argument.

CDEXP returns the double-precision complex exponential function of its double-precision complex argument.