HyperbolicClass added

More efficient calculation of hyperbolic basis for high-dimensional inputs.

src/UQpy/surrogates/polynomial_chaos/polynomials/HyperbolicBasis.py

@@ -0,0 +1,27 @@
+from typing import Union
+
+import numpy as np
+
+from UQpy.distributions.baseclass import Distribution
+from UQpy.distributions.collection import JointIndependent, JointCopula
+from UQpy.surrogates.polynomial_chaos.polynomials.baseclass.PolynomialBasis import PolynomialBasis
+
+
+class HyperbolicBasis(PolynomialBasis):
+
+    def __init__(self, distributions: Union[Distribution, list[Distribution]], max_degree: int, hyperbolic: float = 1):
+        """
+        Create hyperbolic from total-degree polynomial basis.
+        :param distributions: List of univariate distributions.
+        :param max_degree: Maximum polynomial degree of the 1D chaos polynomials.
+        :param hyperbolic: Parameter of hyperbolic truncation reducing interaction terms <0,1>
+        """
+        inputs_number = 1 if not isinstance(distributions, (JointIndependent, JointCopula)) \
+            else len(distributions.marginals)
+        multi_index_set = PolynomialBasis.calculate_hyperbolic_set(inputs_number=inputs_number,
+                                                                     degree=max_degree,q=hyperbolic)
+        if 0 < hyperbolic < 1:
+            mask = np.round(np.sum(multi_index_set ** hyperbolic, axis=1) ** (1 / hyperbolic), 4) <= max_degree
+            multi_index_set = multi_index_set[mask]
+        polynomials = PolynomialBasis.construct_arbitrary_basis(inputs_number, distributions, multi_index_set)
+        super().__init__(inputs_number, len(multi_index_set), multi_index_set, polynomials, distributions)