CARG

This function evaluates the argument of a complex number.

Function Return Value

CARG — Function value. (Output)
If z = x + iy, then arctan(y/x) is returned except when both x and y are zero. In this case, zero is returned.

Required Arguments

Z — Complex number for which the argument is to be evaluated. (Input)

FORTRAN 90 Interface

Generic: CARG (Z)

Specific: The specific interface names are S_CARG and D_CARG.

FORTRAN 77 Interface

Single: CARG (Z)

Double: The double precision function name is ZARG.

Description

Arg(z) is the angle θ in the polar representation z = ∣z∣eiθ, where .

If z = x + iy, then θ = tan‑1 (y/x) except when both x and y are zero. In this case, θ is defined to be zero

Example

In this example, Arg(1 + i) is computed and printed.

 

USE CARG_INT

USE UMACH_INT

 

IMPLICIT NONE

! Declare variables

INTEGER NOUT

REAL VALUE

COMPLEX Z

! Compute

Z = (1.0, 1.0)

VALUE = CARG(Z)

! Print the results

CALL UMACH (2, NOUT)

WRITE (NOUT,99999) Z, VALUE

99999 FORMAT (' CARG(', F6.3, ',', F6.3, ') = ', F6.3)

END

Output

 

CARG( 1.000, 1.000) = 0.785