ASIN
This function extends FORTRAN’s generic ASIN function to evaluate the complex arc sine.
Function Return Value
ASIN — Complex function value in units of radians and the real part in the first or fourth quadrant. (Output)
Required Arguments
ZINP — Complex argument for which the arc sine is desired. (Input)
FORTRAN 90 Interface
Generic: ASIN (ZINP)
Specific: The specific interface names are CASIN and ZASIN.
FORTRAN 77 Interface
Complex: CASIN (ZINP)
Double complex:  The double complex function name is ZASIN.
Description
Almost all arguments are legal. Only when z > b/2 can an overflow occur. Here, b = AMACH(2) is the largest floating point number. This error is not detected by ASIN.
See Pennisi (1963, page 126) for reference.
Example
In this example, sin‑1(1  i) is computed and printed.
 
USE ASIN_INT
USE UMACH_INT
 
IMPLICIT NONE
! Declare variables
INTEGER NOUT
COMPLEX VALUE, Z
! Compute
Z = (1.0, -1.0)
VALUE = ASIN(Z)
! Print the results
CALL UMACH (2, NOUT)
WRITE (NOUT,99999) Z, VALUE
99999 FORMAT (' ASIN((', F6.3, ',', F6.3, ')) = (', &
F6.3, ',', F6.3, ')')
END
Output
 
ASIN(( 1.000,-1.000)) = ( 0.666,-1.061)
Published date: 03/19/2020
Last modified date: 03/19/2020