Plotting spline bases

This example demonstrates how to plot the spline bases of the library.

Imports

Import the necessary libraries and utility functions to define spline bases.

import numpy as np
import matplotlib.pyplot as plt
from splineops.bases.utils import basis_map, create_basis

Function to plot bases

Define a helper function to plot spline bases.

def plot_bases(names, x_values, title):
    plt.figure(figsize=(12, 6))
    for name in names:
        # Convert the base name to a more readable format
        if name == "keys":
            # Special case for Keys spline: no degree in the label
            readable_name = "Keys Spline"
        else:
            name_parts = name.split("-")
            readable_name = f"{name_parts[0][:-1]} degree {name_parts[0][-1]}"

        # Evaluate the basis function
        y_values = create_basis(name).eval(x_values)
        plt.plot(x_values, y_values, label=readable_name)

    plt.title(title)
    plt.xlabel("x")
    plt.ylabel("y")
    plt.grid(True)
    plt.legend()
    plt.show()

Spline bases evaluation and plotting

Define the x range and plot the spline bases in figures.

x_values = np.linspace(-3, 3, 1000)

Combined plot for B-spline degrees 0 to 9

plot_bases(
    names=[
        "bspline0",
        "bspline1",
        "bspline2",
        "bspline3",
        "bspline4",
        "bspline5",
        "bspline6",
        "bspline7",
        "bspline8",
        "bspline9",
    ],
    x_values=x_values,
    title="B-Spline Basis Functions: B-Spline degree 0 to B-Spline degree 9",
)

Combined plot for O-MOMS degrees 0 to 5

plot_bases(
    names=["omoms0", "omoms1", "omoms2", "omoms3", "omoms4", "omoms5"],
    x_values=x_values,
    title="OMOMS Basis Functions: OMOMS degree 0 to OMOMS degree 5",
)

Plot for Keys basis function

plot_bases(
    names=["keys"],
    x_values=x_values,
    title="Keys Basis Function",
)