Beispiel #1
0
def sector(ray1, ray2, **extra_options):
    r"""
    Plot a sector between ``ray1`` and ``ray2`` centered at the origin.

    .. NOTE::

        This function was intended for plotting strictly convex cones, so it
        plots the smaller sector between ``ray1`` and ``ray2`` and, therefore,
        they cannot be opposite. If you do want to use this function for bigger
        regions, split them into several parts.

    .. NOTE::

        As of version 4.6 Sage does not have a graphic primitive for sectors in
        3-dimensional space, so this function will actually approximate them
        using polygons (the number of vertices used depends on the angle
        between rays).

    INPUT:

    - ``ray1``, ``ray2`` -- rays in 2- or 3-dimensional space of the same
      length;

    - ``extra_options`` -- a dictionary of options that should be passed to
      lower level plotting functions.

    OUTPUT:

    - a plot.

    EXAMPLES::

        sage: from sage.geometry.toric_plotter import sector
        sage: print sector((1,0), (0,1))
        Graphics object consisting of 1 graphics primitive
        sage: print sector((3,2,1), (1,2,3))
        Graphics3d Object
    """
    ray1 = vector(RDF, ray1)
    ray2 = vector(RDF, ray2)
    r = ray1.norm()
    if len(ray1) == 2:
        # Plot an honest sector
        phi1 = arctan2(ray1[1], ray1[0])
        phi2 = arctan2(ray2[1], ray2[0])
        if phi1 > phi2:
            phi1, phi2 = phi2, phi1
        if phi2 - phi1 > pi:
            phi1, phi2 = phi2, phi1 + 2 * pi
        return disk((0, 0), r, (phi1, phi2), **extra_options)
    else:
        # Plot a polygon, 30 vertices per radian.
        vertices_per_radian = 30
        n = ceil(arccos(ray1 * ray2 / r**2) * vertices_per_radian)
        dr = (ray2 - ray1) / n
        points = (ray1 + i * dr for i in range(n + 1))
        points = [r / pt.norm() * pt for pt in points]
        points.append(vector(RDF, 3))
        return polygon(points, **extra_options)
Beispiel #2
0
def sector(ray1, ray2, **extra_options):
    r"""
    Plot a sector between ``ray1`` and ``ray2`` centered at the origin.

    .. NOTE::

        This function was intended for plotting strictly convex cones, so it
        plots the smaller sector between ``ray1`` and ``ray2`` and, therefore,
        they cannot be opposite. If you do want to use this function for bigger
        regions, split them into several parts.

    .. NOTE::

        As of version 4.6 Sage does not have a graphic primitive for sectors in
        3-dimensional space, so this function will actually approximate them
        using polygons (the number of vertices used depends on the angle
        between rays).

    INPUT:

    - ``ray1``, ``ray2`` -- rays in 2- or 3-dimensional space of the same
      length;

    - ``extra_options`` -- a dictionary of options that should be passed to
      lower level plotting functions.

    OUTPUT:

    - a plot.

    EXAMPLES::

        sage: from sage.geometry.toric_plotter import sector
        sage: sector((1,0), (0,1))
        Graphics object consisting of 1 graphics primitive
        sage: sector((3,2,1), (1,2,3))
        Graphics3d Object
    """
    ray1 = vector(RDF, ray1)
    ray2 = vector(RDF, ray2)
    r = ray1.norm()
    if len(ray1) == 2:
        # Plot an honest sector
        phi1 = arctan2(ray1[1], ray1[0])
        phi2 = arctan2(ray2[1], ray2[0])
        if phi1 > phi2:
            phi1, phi2 = phi2, phi1
        if phi2 - phi1 > pi:
            phi1, phi2 = phi2, phi1 + 2 * pi
        return disk((0,0), r, (phi1, phi2), **extra_options)
    else:
        # Plot a polygon, 30 vertices per radian.
        vertices_per_radian = 30
        n = ceil(arccos(ray1 * ray2 / r**2) * vertices_per_radian)
        dr = (ray2 - ray1) / n
        points = (ray1 + i * dr for i in range(n + 1))
        points = [r / pt.norm() * pt for pt in points]
        points.append(vector(RDF, 3))
        return polygon(points, **extra_options)