X-Git-Url: https://scm.cri.ensmp.fr/git/linpy.git/blobdiff_plain/dbe638f61f1927ee6f3dffaaf2dc34418725f50a..98edd00eb4b05e85f7cb1b85cff2f4d733909c57:/doc/examples.rst diff --git a/doc/examples.rst b/doc/examples.rst deleted file mode 100644 index b552b7f..0000000 --- a/doc/examples.rst +++ /dev/null @@ -1,118 +0,0 @@ - -.. _examples: - -Examples -======== - -Basic Examples --------------- - -To create any polyhedron, first define the symbols used. -Then use the polyhedron functions to define the constraints. -The following is a simple running example illustrating some different operations and properties that can be performed by LinPy with two squares. - ->>> from linpy import * ->>> x, y = symbols('x y') ->>> # define the constraints of the polyhedron ->>> square1 = Le(0, x) & Le(x, 2) & Le(0, y) & Le(y, 2) ->>> square1 -And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0)) - -Binary operations and properties examples: - ->>> # create a polyhedron from a string ->>> square2 = Polyhedron('1 <= x') & Polyhedron('x <= 3') & \ - Polyhedron('1 <= y') & Polyhedron('y <= 3') ->>> #test equality ->>> square1 == square2 -False ->>> # compute the union of two polyhedra ->>> square1 | square2 -Or(And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0)), \ - And(Ge(x - 1, 0), Ge(-x + 3, 0), Ge(y - 1, 0), Ge(-y + 3, 0))) ->>> # check if square1 and square2 are disjoint ->>> square1.disjoint(square2) -False ->>> # compute the intersection of two polyhedra ->>> square1 & square2 -And(Ge(x - 1, 0), Ge(-x + 2, 0), Ge(y - 1, 0), Ge(-y + 2, 0)) ->>> # compute the convex union of two polyhedra ->>> Polyhedron(square1 | sqaure2) -And(Ge(x, 0), Ge(y, 0), Ge(-y + 3, 0), Ge(-x + 3, 0), \ - Ge(x - y + 2, 0), Ge(-x + y + 2, 0)) - -Unary operation and properties examples: - ->>> square1.isempty() -False ->>> # compute the complement of square1 ->>> ~square1 -Or(Ge(-x - 1, 0), Ge(x - 3, 0), And(Ge(x, 0), Ge(-x + 2, 0), \ - Ge(-y - 1, 0)), And(Ge(x, 0), Ge(-x + 2, 0), Ge(y - 3, 0))) ->>> square1.symbols() -(x, y) ->>> square1.inequalities -(x, -x + 2, y, -y + 2) ->>> # project out the variable x ->>> square1.project([x]) -And(Ge(-y + 2, 0), Ge(y, 0)) - -Plot Examples -------------- - -LinPy can use the matplotlib plotting library to plot 2D and 3D polygons. -This can be a useful tool to visualize and compare polygons. -The user has the option to pass plot objects to the :meth:`Domain.plot` method, which provides great flexibility. -Also, keyword arguments can be passed such as color and the degree of transparency of a polygon. - ->>> import matplotlib.pyplot as plt ->>> from matplotlib import pylab ->>> from mpl_toolkits.mplot3d import Axes3D ->>> from linpy import * ->>> # define the symbols ->>> x, y, z = symbols('x y z') ->>> fig = plt.figure() ->>> cham_plot = fig.add_subplot(1, 1, 1, projection='3d', aspect='equal') ->>> cham_plot.set_title('Chamfered cube') ->>> cham = Le(0, x) & Le(x, 3) & Le(0, y) & Le(y, 3) & Le(0, z) & \ - Le(z, 3) & Le(z - 2, x) & Le(x, z + 2) & Le(1 - z, x) & \ - Le(x, 5 - z) & Le(z - 2, y) & Le(y, z + 2) & Le(1 - z, y) & \ - Le(y, 5 - z) & Le(y - 2, x) & Le(x, y + 2) & Le(1 - y, x) & Le(x, 5 - y) ->>> cham.plot(cham_plot, facecolor='red', alpha=0.75) ->>> pylab.show() - -.. figure:: images/cham_cube.jpg - :align: center - -LinPy can also inspect a polygon's vertices and the integer points included in the polygon. - ->>> diamond = Ge(y, x - 1) & Le(y, x + 1) & Ge(y, -x - 1) & Le(y, -x + 1) ->>> diamond.vertices() -[Point({x: Fraction(0, 1), y: Fraction(1, 1)}), \ - Point({x: Fraction(-1, 1), y: Fraction(0, 1)}), \ - Point({x: Fraction(1, 1), y: Fraction(0, 1)}), \ - Point({x: Fraction(0, 1), y: Fraction(-1, 1)})] ->>> diamond.points() -[Point({x: -1, y: 0}), Point({x: 0, y: -1}), Point({x: 0, y: 0}), \ - Point({x: 0, y: 1}), Point({x: 1, y: 0})] - -The user also can pass another plot to the :meth:`Domain.plot` method. -This can be useful to compare two polyhedra on the same axis. -This example illustrates the union of two squares. - ->>> from linpy import * ->>> import matplotlib.pyplot as plt ->>> from matplotlib import pylab ->>> x, y = symbols('x y') ->>> square1 = Le(0, x) & Le(x, 2) & Le(0, y) & Le(y, 2) ->>> square2 = Le(1, x) & Le(x, 3) & Le(1, y) & Le(y, 3) ->>> fig = plt.figure() ->>> plot = fig.add_subplot(1, 1, 1, aspect='equal') ->>> square1.plot(plot, facecolor='red', alpha=0.3) ->>> square2.plot(plot, facecolor='blue', alpha=0.3) ->>> squares = Polyhedron(square1 + square2) ->>> squares.plot(plot, facecolor='blue', alpha=0.3) ->>> pylab.show() - -.. figure:: images/union.jpg - :align: center