feat : Addition of Non Linear Norm Factor using Vandermonde Matrix

[Ragansu]

Overview

Many physical processes involve parameters that exhibit nonlinear relationships across multiple samples. Such processes can be modeled by solving systems of equations constructed using a Vandermonde matrix.

Changes Introduced

This pull request introduces support for this functionality within the framework. Specifically:

• Users are only required to define the basis.
• The WorkspaceMaker class automatically computes the corresponding Vandermonde matrix.
• The computed matrix is added to the workspace.
• The feature is fully integrated into the normalization workflow within the sbi_parametric_model class.

Additional Updates

Due to the nonlinear nature of these relationships, it is necessary to define observations separately from template samples. This pull request includes the required modifications to support this distinction. (WorkspaceBuilder.observations())

Testing

This feature has been tested to ensure correctness and stability.

RC