Radviz

Radviz maps a higher dimensional space with a non-linear function to two dimensions. Let us visualize some test data:

[1]:

from pymoo.util.ref_dirs import get_reference_directions
from pymoo.problems import get_problem


ref_dirs = get_reference_directions("uniform", 6, n_partitions=5)
F = get_problem("dtlz1").pareto_front(ref_dirs)

A simple Radviz plot with points can be created by:

[2]:

from pymoo.visualization.radviz import Radviz
Radviz().add(F).show()

[2]:

<pymoo.visualization.radviz.Radviz at 0x108f97a40>
../_images/visualization_radviz_5_1.png

The plot can be further customized by supplying a title, labels, and by using the plotting directives from matplotlib.

[3]:

plot = Radviz(title="Optimization",
              legend=(True, {'loc': "upper left", 'bbox_to_anchor': (-0.1, 1.08, 0, 0)}),
              labels=["profit", "cost", "sustainability", "environment", "satisfaction", "time"],
              endpoint_style={"s": 70, "color": "green"})
plot.set_axis_style(color="black", alpha=1.0)
plot.add(F, color="grey", s=20)
plot.add(F[65], color="red", s=70, label="Solution A")
plot.add(F[72], color="blue", s=70, label="Solution B")
plot.show()

[3]:

<pymoo.visualization.radviz.Radviz at 0x130978680>
../_images/visualization_radviz_7_1.png

Note that radviz plots are by default normalized.

API

class pymoo.visualization.radviz.Radviz(self, endpoint_style={}, **kwargs)

Radviz Plot

Parameters
axis_styledict

Most of the plots consists of an axis. The style of the axis, e.g. color, alpha, …, can be changed to further modify the plot appealing.

endpoint_styledict

Endpoints are drawn at each extreme point of an objective. This style can be modified.

labelsstr or list

The labels to be used for each variable provided in the plot. If a string is used, then they will be enumerated. Otherwise, a list equal to the number of variables can be provided directly.

Other Parameters
figsizetuple

The figure size. Default (figsize=(8, 6)). For some plots changing the size might have side-effects for position.

titlestr or tuple

The title of the figure. If some additional kwargs should be provided this can be achieved by providing a tuple (“name”, {“key” : val}).

legendstr

Whether a legend should be shown or not.

tight_layoutbool

Whether tight layout should be used.

cmapcolormap

For some plots different kind of colors are used. The colormap can be changed to modify the color sequence for the plots.