public elemental function face_normal4_R4P(pt1, pt2, pt3, pt4, norm) result(normal)
Calculate the normal of the face defined by 4 points.
The convention for the points numeration is the following:
3.----------.2
| |
| |
| |
| |
4.----------.1
The normal is calculated by the cross product of the diagonal d13 for the diagonal d24: d13 x d24.
The normal is normalized if the variable norm is passed (with any value).
Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.
Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.