Visualize pairs between two samples

In this example we visualize the relationships between the marginal samples of two given samples. This is usual when we analyze the relationship of output sample of a model depending on input sample. This can be achieved by plotting the outputs versus the inputs. When there are several inputs (which is the most often encountered case) and several outputs (which is less often). The DrawPairsXY() method provides a tool to plot the pairs of input and output marginal samples and see the correlations graphically.

import openturns as ot
import openturns.viewer as viewer

ot.Log.Show(ot.Log.NONE)

Create the model

model = ot.SymbolicFunction(
    ["X0", "X1", "X2"],
    ["1.0 + 2.0 * X0 - 1.0 * X1 + 4.0 * X2", "-2.0 - 3.0 * X0 + 5.0 * X1 - 1.0 * X2"],
)

Create the input data to visualize

distribution = ot.Normal(3)
distribution.setDescription(model.getInputDescription())
input_sample = distribution.getSample(100)

output_sample = model(input_sample)

graph = ot.VisualTest.DrawPairsXY(input_sample, output_sample)
graph.setTitle("Clouds of input / output samples")
view = viewer.View(graph)
viewer.View.ShowAll()