Compiler Library/XL Reference Manual (32650-90029)

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Attributes

Parameter: A longreal number.

Result: A representable longreal number in the range

[0.0, 1.0]. See Chapter 1 for details on the

internal representation of longreal numbers.

HP FORTRAN 77/XL: Intrinsic function: Y=DTANH(X).

Error: If the argument is a NaN, there are two

possible actions. If the INVALID trap is

enabled, the message "DTANH(X): X=NaN" occurs.

Otherwise, the INVALID flag is set. In either

case, a quiet NaN is returned.

EXP (or EXP')

EXP calculates

, where

is a real number.

Declaration

FUNCTION EXP(VAR x:REAL):REAL; EXTERNAL;

Accuracy

Attributes

Parameter: A representable real number in the range

[-87.3366, 88.7228]. See Chapter 1 for details

on the internal representation of real numbers.

Result: A representable positive real number.

HP FORTRAN 77/XL: Intrinsic function: Y=EXP(X).

Error: If the argument is a NaN, there are two cases.

If the INVALID trap is enabled, the message

"EXP(X): X=NaN" occurs. Otherwise, the INVALID

flag is set. In either case, a quiet NaN is

returned.

If the argument is >= 88.722839, the message

"EXP(X) OVERFLOW" occurs and the result is

infinity. If the argument is <= -87.336548,

the message "EXP(X) UNDERFLOW" occurs and the

result is set to zero.

Special Values

exp (+Infinity) = +Infinity

exp (-Infinity) = 0

IFIX (or IFIX')

IFIX truncates a real number to a shortint number.

Declaration

FUNCTION IFIX(x:REAL):SHORTINT; EXTERNAL;