Implementation:Interpretml Interpret InterpretableNumerics

Knowledge Sources	Interpretml Interpret
Domains	Machine_Learning, EBM_Core
Last Updated	2026-02-07 12:00 GMT

Overview

InterpretableNumerics is a C++ module that provides human-readable cut point generation and numerically safe mathematical operations for the EBM framework.

Description

This module implements two major categories of functionality:

Interpretable Cut Point Generation:

The core innovation is selecting cut points between adjacent feature values that are human-readable (e.g., "2.5" rather than "2.4999999999999996"). Key functions include:

• ArithmeticMean: Computes the arithmetic mean of two doubles using the overflow-safe formula low * 0.5 + high * 0.5, with careful handling of IEEE 754 edge cases.
• GeometricMeanPositives: Computes the geometric mean of two positive doubles using exp((log(low) + log(high)) * 0.5), falling back to arithmetic mean if numerical issues arise.
• FloatToFullString: Converts a double to its full scientific notation string representation in a standardized format for cross-platform reproducibility.
• GetInterpretableCutPointFloat: The central function that finds a human-interpretable cut point between two adjacent values. It progressively shortens the string representation of the midpoint, choosing the shortest string that still falls between the two values.
• GetInterpretableEndpoint: Finds interpretable graph boundary endpoints by adjusting from the center point toward the edges.
• RemoveMissingValsAndReplaceInfinities: Preprocesses feature values by removing NaN and replacing infinities with min/max representable values.
• SuggestGraphBounds: EBM API function that suggests graph display boundaries for feature visualizations.
• GetHistogramCutCount: Determines the optimal number of histogram bins for a given feature.

Numerically Safe Operations:

• SafeSum: Computes the sum of an array with overflow protection.
• SafeMean: Computes the mean with safe summation.
• SafeStandardDeviation: Computes standard deviation with safe summation using the two-pass algorithm.
• SafeExp: Applies exponential function with clamping to prevent overflow.
• SafeLog: Applies logarithm with clamping to prevent negative infinity.

Usage

The interpretable cut point functions are called during feature discretization to produce human-readable bin boundaries. The safe math functions are available through the public API for use by higher-level Python/R code when processing model outputs.

Code Reference

Source Location

• Repository: Interpretml_Interpret
• File: shared/libebm/interpretable_numerics.cpp

Signature

// Interpretable cut points
extern double ArithmeticMean(const double low, const double high) noexcept;
extern double GetInterpretableCutPointFloat(
    double low, double high) noexcept;
extern double GetInterpretableEndpoint(
    const double center, const double movementFromEnds) noexcept;
extern size_t RemoveMissingValsAndReplaceInfinities(
    const size_t cSamples, double* const aVals) noexcept;

// Float/String conversion
extern IntEbm GetCountCharactersPerFloat();
extern ErrorEbm FloatsToString(IntEbm count, const double* vals, char* str);
extern ErrorEbm StringToFloats(const char* str, double* vals);

// Public API functions
EBM_API_BODY ErrorEbm EBM_CALLING_CONVENTION SuggestGraphBounds(
    IntEbm countCuts, const double* cuts,
    double minFeatureVal, double maxFeatureVal,
    double* lowGraphBoundOut, double* highGraphBoundOut);

EBM_API_BODY ErrorEbm EBM_CALLING_CONVENTION SafeSum(
    IntEbm count, const double* vals, double* sumOut);
EBM_API_BODY ErrorEbm EBM_CALLING_CONVENTION SafeMean(
    IntEbm count, const double* vals, double* meanOut);
EBM_API_BODY ErrorEbm EBM_CALLING_CONVENTION SafeStandardDeviation(
    IntEbm count, const double* vals, double* stddevOut);
EBM_API_BODY void EBM_CALLING_CONVENTION SafeExp(
    IntEbm count, double* inout);
EBM_API_BODY void EBM_CALLING_CONVENTION SafeLog(
    IntEbm count, double* inout);
EBM_API_BODY IntEbm EBM_CALLING_CONVENTION GetHistogramCutCount(
    IntEbm countSamples, const double* featureVals);

I/O Contract

Inputs

Name	Type	Required	Description
low	double	Yes	Lower bound value for cut point calculation
high	double	Yes	Upper bound value for cut point calculation
count	IntEbm	Yes	Number of values for safe math operations
vals	const double*	Yes	Array of values for safe math operations
countCuts	IntEbm	Yes	Number of cut points for graph bounds
cuts	const double*	Yes	Cut point array for graph bounds

Outputs

Name	Type	Description
return (ArithmeticMean)	double	Midpoint between low and high
return (GetInterpretableCutPointFloat)	double	Human-readable cut point between low and high
sumOut / meanOut / stddevOut	double*	Safe numerical computation results
lowGraphBoundOut / highGraphBoundOut	double*	Suggested graph display boundaries

Usage Examples

Pipeline Context

# This C++ module is called internally via the native bindings
# during discretization for human-readable cut points
from interpret.glassbox import ExplainableBoostingClassifier
ebm = ExplainableBoostingClassifier()
ebm.fit(X, y)  # Internally calls GetInterpretableCutPointFloat for bin edges

Related Pages

• Environment:Interpretml_Interpret_Native_Libebm_Environment