Vector operations example for FORTRAN90.

VectorOperations

MODULE VectorMathMod
IMPLICIT NONE
REAL*8 :: PI
PI = ACOS(0.0D0)*2.D0

TYPE Vector
REAL*8 :: X
REAL*8 :: Y
REAL*8 :: Z
END TYPE Vector

INTERFACE ABS
MODULE PROCEDURE VLength
END INTERFACE

INTERFACE OPERATOR (+)
MODULE PROCEDURE Add
END INTERFACE

INTERFACE OPERATOR (-)
MODULE PROCEDURE Substract
END INTERFACE

INTERFACE OPERATOR (*)
MODULE PROCEDURE MultScalar
END INTERFACE

INTERFACE OPERATOR (**)
MODULE PROCEDURE MultVector
END INTERFACE

CONTAINS
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!---FUNCTIONS---!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

TYPE(Vector) FUNCTION Add(vector1, vector2)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2

Add.X = vector1.X + vector2.X
Add.Y = vector1.Y + vector2.Y
Add.Z = vector1.Z + vector2.Z
END FUNCTION Add

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

TYPE(Vector) FUNCTION Substract(vector1, vector2)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2

Substract.X = vector1.X - vector2.X
Substract.Y = vector1.Y - vector2.Y
Substract.Z = vector1.Z - vector2.Z
END FUNCTION Substract

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

TYPE(Vector) FUNCTION Multiply(vector1, coeff)
IMPLICIT NONE
TYPE(Vector), INTENT(IN):: vector1
REAL*8, INTENT(IN) :: coeff

Multiply.X = vector1.X*coeff
Multiply.Y = vector1.Y*coeff
Multiply.Z = vector1.Z*coeff
END FUNCTION Multiply

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

REAL*8 FUNCTION VLength(vect)
IMPLICIT NONE
TYPE(Vector) :: vect

VLength = SQRT(vect.X**2 + vect.Y**2 + vect.Z**2)
END FUNCTION VLength

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

REAL*8 FUNCTION VAngle(vector1, vector2)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2

VAngle = (vector1.X*vector2.X + vector1.Y*vector2.Y + vector1.Z*vector2.Z) &
/ (VLength(vector1)*VLength(vector2))

END FUNCTION VAngle

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

REAL*8 FUNCTION MultScalar(vector1, vector2)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2

MultScalar = VLength(vector1)*VLength(vector2)*VAngle(vector1, vector2)

END FUNCTION MultScalar

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

TYPE(Vector) FUNCTION MultVector(vector1, vector2)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2
MultVector.X = vector1.Y*vector2.Z - vector2.Y*vector1.Z
MultVector.Y = vector1.Z*vector2.X - vector2.Z*vector1.X
MultVector.Z = vector1.X*vector2.Y - vector2.X*vector1.Y
! CHECK FOR: {3, -4, -8} AND {-5, 2, -1}
! RESULT IS {20, 43, -14}
END FUNCTION MultVector

REAL*8 FUNCTION MultMixed(vector1, vector2, vector3)
IMPLICIT NONE
TYPE(Vector), INTENT(IN) :: vector1, vector2, vector3

MultMixed = MultScalar(vector1, MultVector(vector2, vector3))

END FUNCTION MultMixed

END MODULE VectorMathMod