HP 3000 Manuals

Compiler Library/XL Reference Manual

ALOG (or ALOG') or ALOG10 

ALOG calculates the natural logarithm of a positive real number; ALOG10
calculates the base 10 logarithm of a positive real number.

Declaration 

FUNCTION ALOG(VAR x:REAL):REAL; EXTERNAL;
                or

FUNCTION ALOG10(VAR x:REAL):REAL; EXTERNAL;

Accuracy 



Attributes 

Parameter:                A positive real number.

Result:                   A real number (ALOG10 = ALOG*log10 (e)).

HP FORTRAN 77/XL:         Intrinsic function ALOG(X) or ALOG10(X).

Error:                    If the argument is a NaN or if it is negative,
                          there are two possible actions.  If the INVALID
                          trap is enabled, the message "ALOG(X): X< 0.0
                          OR X=NaN" or "ALOG10(X): X< 0.0 OR X=NaN"
                          occurs.  Otherwise, the INVALID flag is set.
                          In either case, a quiet NaN is returned.  See
                          Appendix A, "Compiler Library Messages" for
                          more details.

Special Values 

                 alog (+Infinity) = +Infinity

                 alog (0) = -Infinity

MPE/iX 5.0 Documentation