Hyperbolic arc sine (Inverse hyperbolic sine)

subroutine arcsinh(x,y)

! Description:

!

! Author: aym

!

! Host: aofd30

! Directory: /work1/aym/11.Work10/36.vertical2d/26.2dv_Slope_3/prep

!

! Revision history:

!  2011-03-04 17:26

!    Initial Version

!

! Reference

!     Abramowitz and Stegun, 1965. Handbook of mathematical functions, Dover

!     Figure 4.8 (p. 87)

!  use

!  implicit none

!  write(*,'(a)')'Subroutine: arcsinh'

!  write(*,*)''

  y=log(x+sqrt(x**2 + 1))

!  write(*,'(a)')'Done subroutine arcsinh.'

!  write(*,*)

end subroutine arcsinh