def locate(self, point):
r"""Find a point on the current curve.
Solves for :math:`s` in :math:`B(s) = p`.
This method acts as a (partial) inverse to :meth:`evaluate`.
.. note::
A unique solution is only guaranteed if the current curve has no
self-intersections. This code assumes, but doesn't check, that
this is true.
.. image:: ../images/curve_locate.png
:align: center
.. doctest:: curve-locate
>>> nodes = np.asfortranarray([
... [0.0, 0.0],
... [1.0, 2.0],
... [3.0, 1.0],
... [4.0, 0.0],
... ])
>>> curve = bezier.Curve(nodes, degree=3)
>>> point1 = np.asfortranarray([[3.09375, 0.703125]])
>>> s = curve.locate(point1)
>>> s
0.75
>>> point2 = np.asfortranarray([[2.0, 0.5]])
>>> curve.locate(point2) is None
True
.. testcleanup:: curve-locate
import make_images
make_images.curve_locate(curve, point1, point2)
Args:
point (numpy.ndarray): A (``1xD``) point on the curve,
where :math:`D` is the dimension of the curve.
Returns:
Optional[float]: The parameter value (:math:`s`) corresponding
to ``point`` or :data:`None` if the point is not on
the ``curve``.
Raises:
ValueError: If the dimension of the ``point`` doesn't match the
dimension of the current curve.
"""
if point.shape != (1, self._dimension):
point_dimensions = ' x '.join(
str(dimension) for dimension in point.shape)
msg = _LOCATE_ERROR_TEMPLATE.format(self._dimension,
self._dimension, point,
point_dimensions)
raise ValueError(msg)
return _curve_helpers.locate_point(self, point)
def _call_function_under_test(curve, point):
from bezier import _curve_helpers
return _curve_helpers.locate_point(curve, point)