8.1.2 Formex class members

f
The attribute f holds the coordinates of all points in the Formex. It is a Coords type object with shape (nelems,nplex,3), where nplex is nonzero. An empty Formex has nelems == 0.

The class offers methods to access the coordinates in groups or individually. For performance reasons, the attribute can be changed directly, but you should make sure that f always stays a Coords type object with proper shape.

p
Either an integer array with shape (nelems,), or None. If not None, an integer value is attributed to each element of the Formex. There is no provision to attribute different values to the separate nodes of an element. If you need such functionality, use the p array as a pointer into a data structure that has different values per node.

The p is called property number or property for short. If it is not None, it will take part in the Formex transformations and its values will propagate to all copies created from the Formex elements.