HP 3000 Manuals

Compiler Library/XL Reference Manual

ATAN2 (or ATAN2') 

ATAN2 calculates the arctangent of the quotient of two real numbers.

Declaration 

     FUNCTION ATAN2(VAR x,y:REAL):REAL; EXTERNAL;

Accuracy 



Attributes 

Parameters:               Real numbers; both must not be zero.

Result:                   A representable real number in one of the
                          following ranges:


                          See Chapter 1 for details on the internal
                          representation of real numbers.

HP FORTRAN 77/XL:         Intrinsic function:  Z=ATAN2(X,Y)

Error:                    If either of the arguments is a NaN or if both
                          arguments are zero (or Infinity), there are two
                          possible actions.  If the INVALID trap is
                          enabled, the message "ATAN2(X,Y): X=Y=0.0 OR
                          X=Y=INFINITY OR ANY OF X AND Y=NaN" occurs.
                          Otherwise, the INVALID flag is set.  In either
                          case, a quiet NaN is returned.

                          See Appendix A for more details.

MPE/iX 5.0 Documentation