LINSPACE3: linearly spaced vector defined by three points

Generate a vector as linearly spaced as possible while still including three defined points.

LINSPACE3 linearly spaced vector including a defined middle point.
LINSPACE3(X1, X2, X3) generates a row vector of 100 points between X1 and X3 as linearly spaced as possible such that the vector contains X2.

LINSPACE3(X1, X2, X3, N) generates a row vector of N points.

[V, IND] = LINSPACE3(...) also returns the index, IND, of X2 in the vector.

LINSPACE3 will always contain X1, X2, and X3 without repeating an element.

For N < 3, LINSPACE3 returns the shortest possible vector containing all of X1, X2, and X3. This is normally [X1 X2 X3]. However, if X1=X2 or X2=X3, LINSPACE3 returns [X1 X3].

One use of LINSPACE3 is, for example, in generating points to evaluate in a sensitivity study where one decision variable, at a certain point (X2), is also restricted by bounds (X1, X3).