Function integrate

lib/matplotlib/streamplot.py:517–557

Return x, y grid-coordinates of trajectory based on starting point. Integrate both forward and backward in time from starting point in grid coordinates. Integration is terminated when a trajectory reaches a domain boundary or when it crosses into an already

(x0, y0, broken_streamlines=True, integration_max_step_scale=1.0,
                  integration_max_error_scale=1.0)

        return -dxi, -dyi

    def integrate(x0, y0, broken_streamlines=True, integration_max_step_scale=1.0,
                  integration_max_error_scale=1.0):
        """
        Return x, y grid-coordinates of trajectory based on starting point.

        Integrate both forward and backward in time from starting point in
        grid coordinates.

        Integration is terminated when a trajectory reaches a domain boundary
        or when it crosses into an already occupied cell in the StreamMask. The
        resulting trajectory is None if it is shorter than `minlength`.
        """

        stotal, xy_traj = 0., []

        try:
            dmap.start_trajectory(x0, y0, broken_streamlines)
        except InvalidIndexError:
            return None
        if integration_direction in ['both', 'backward']:
            s, xyt = _integrate_rk12(x0, y0, dmap, backward_time, maxlength,
                                     broken_streamlines,
                                     integration_max_step_scale,
                                     integration_max_error_scale)
            stotal += s
            xy_traj += xyt[::-1]

        if integration_direction in ['both', 'forward']:
            dmap.reset_start_point(x0, y0)
            s, xyt = _integrate_rk12(x0, y0, dmap, forward_time, maxlength,
                                     broken_streamlines,
                                     integration_max_step_scale,
                                     integration_max_error_scale)
            stotal += s
            xy_traj += xyt[1:]

        if stotal > minlength:
            return np.broadcast_arrays(xy_traj, np.empty((1, 2)))[0]
        else:  # reject short trajectories
            dmap.undo_trajectory()
            return None

    return integrate