注释里详细介绍了如何使用。
subroutine cross_3d ( x1, y1, z1, x2, y2, z2, x3, y3, z3 )
!***************************************************
!! CROSS_3D computes the cross product of two vectors in 3D.
!
! Definition:
!
! The cross product in 3D can be regarded as the determinant of the
! symbolic matrix:
!
! | i j k |
! det | x1 y1 z1 |
! | x2 y2 z2 |
!
! = ( y1 * z2 - z1 * y2 ) * i
! + ( z1 * x2 - x1 * z2 ) * j
! + ( x1 * y2 - y1 * x2 ) * k
! Modified:
! 19 April 1999
! Author:
! John Burkardt
! Parameters:
! Input, real X1, Y1, Z1, X2, Y2, Z2, the coordinates of the vectors.
! Output, real X3, Y3, Z3, the cross product vector.
implicit none
real(8) x1
real(8) x2
real(8) x3
real(8) y1
real(8) y2
real(8) y3
real(8) z1
real(8) z2
real(8) z3
x3 = y1 * z2 - z1 * y2
y3 = z1 * x2 - x1 * z2
z3 = x1 * y2 - y1 * x2
end subroutine cross_3d
