def create_points_grid(grid_limits, n_grid_points):
"""Creates a grid of points.
Parameters
----------
grid_limits : list of tuple
List with a tuple of min/max limits for each axis.
If None, [(0, 1), (0, 1)] limits will be used.
n_grid_points : int
Number of grid points.
"""
grid_bounds = [(0, 1), (0, 1)] if grid_limits is None else grid_limits
x_min, x_max = (grid_bounds[0][0], grid_bounds[0][1])
y_min, y_max = (grid_bounds[1][0], grid_bounds[1][1])
# Padding x and y grid points
padding_x, padding_y = (0.05 * (x_max - x_min), 0.05 * (y_max - y_min))
# Create the equi-spaced indices for each axis
x_grid_points = CArray.linspace(x_min - padding_x,
x_max + padding_x,
num=n_grid_points)
y_grid_points = CArray.linspace(y_min - padding_y,
y_max + padding_y,
num=n_grid_points)
# Create the grid
pad_xgrid, pad_ygrid = CArray.meshgrid((x_grid_points, y_grid_points))
pad_grid_point_features = CArray.concatenate(pad_xgrid.reshape(
(pad_xgrid.size, 1)),
pad_ygrid.reshape(
(pad_ygrid.size, 1)),
axis=1)
return pad_grid_point_features, pad_xgrid, pad_ygrid
def test_quiver(self):
"""Test for `CPlot.quiver()` method."""
# gradient values creation
xv = CArray.arange(0, 2 * constants.pi, .2)
yv = CArray.arange(0, 2 * constants.pi, .2)
X, Y = CArray.meshgrid((xv, yv))
U = CArray.cos(X)
V = CArray.sin(Y)
plot = CFigure()
plot.sp.title('Gradient arrow')
plot.sp.quiver(U, V)
plot.show()
from secml.array import CArray
from secml.figure import CFigure
def f(x, y):
return (1 - x / 2 + x**5 + y**3) * (-x**2 - y**2).exp()
fig = CFigure()
x_linspace = CArray.linspace(-3, 3, 256)
y_linspace = CArray.linspace(-3, 3, 256)
X, Y = CArray.meshgrid((x_linspace, y_linspace))
C = fig.sp.contour(X, Y, f(X, Y), linewidths=.5, cmap='hot')
fig.sp.clabel(C, inline=1, fontsize=10)
fig.sp.xticks(())
fig.sp.yticks(())
fig.show()
