PK_CURVE_find_vector_interval

PK_ERROR_code_t      PK_CURVE_find_vector_interval
(
--- received arguments ---
PK_CURVE_t           curve,     --- curve
PK_VECTOR_t          vector_1,  --- first position vector
PK_VECTOR_t          vector_2,  --- second position vector

--- returned arguments ---
PK_INTERVAL_t *const interval   --- parameter interval bounded by vectors
)


This function returns the parameter interval of a curve bounded by two
position vectors lying on the curve.


Specific Errors:
    PK_ERROR_not_on_curve        'vector_1' or 'vector_2' not on curve (MILD)


The position vectors must lie on the curve within SESSION precision.
The position vectors are parameterised onto the curve yielding say t1 and t2.

For non-periodic curves, the returned interval is

    [ min(t1, t2)  max(t1,t2) ].

For periodic curves, the range of the curve bounded by the returned interval
is that starting from t1 and going in the direction of increasing parameter
until 'vector_2' is reached. If 'vector_1' and 'vector_2' are the same within
SESSION precision, the range is all of the curve and the returned interval is

    [t1 t1+period].