HP 3000 Manuals

Compiler Library/XL Reference Manual

CABS (or CABS') 

CABS calculates the absolute value of a complex number.

Declaration 

     TYPE complex=RECORD
                   realpart:REAL;
                   imagpart:REAL;
                  END;

     FUNCTION CABS(VAR x:complex):REAL; EXTERNAL;

Accuracy 

Depends on the accuracy of SQRT.

Attributes 

Parameter:                Any complex number representable in two real
                          numbers:  one for a and one for b.

Result:                   A non-negative real number.

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

Error:                    If either part of the argument is a NaN, there
                          are two possible actions.  If the INVALID trap
                          is enabled, the message "CABS(X): ANY PART OF
                          X=NaN" occurs.  Otherwise, the INVALID flag is
                          set.  In either case, a quiet NaN is returned.

                          If a and/or b are near the overflow threshold
                          (a and/or b approximately equals to 1038 ), the
                          message "CABS OVERFLOW" occurs.  See Appendix A
                          for more details.

MPE/iX 5.0 Documentation