r"""
Plotting a vector field
=======================

This example shows how to initialize and visualize the vector field 
:math:`\boldsymbol u = \bigl(\sin(x), \cos(x)\bigr)`.
"""

from pde import CartesianGrid, VectorField

grid = CartesianGrid([[-2, 2], [-2, 2]], 32)
field = VectorField.from_expression(grid, ["sin(x)", "cos(x)"])
field.plot(method="streamplot", title="Stream plot")