spartan2 0.9.0

High-speed zkSNARKs without trusted setup
Documentation 
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// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: MIT
// This file is part of the Spartan2 project.
// See the LICENSE file in the project root for full license information.
// Source repository: https://github.com/Microsoft/Spartan2

//! Mathematical utility functions for Spartan.
//!
//! This module provides basic mathematical operations needed throughout the codebase,
//! particularly for computing logarithms used in polynomial degree calculations.

/// Trait providing mathematical utility functions.
pub trait Math {
  /// Computes the base-2 logarithm of the value.
  ///
  /// For powers of two, returns the exact logarithm.
  /// For other values, returns the floor of the logarithm.
  ///
  /// # Panics
  /// Panics if the value is zero.
  fn log_2(self) -> usize;
}

impl Math for usize {
  fn log_2(self) -> usize {
    assert_ne!(self, 0);

    if self.is_power_of_two() {
      (1usize.leading_zeros() - self.leading_zeros()) as usize
    } else {
      (0usize.leading_zeros() - self.leading_zeros()) as usize
    }
  }
}