r"""
This file contains utility functions to convert values
using APoT nonuniform quantization methods.
"""

import math

r"""Converts floating point input into APoT number
    based on quantization levels
"""
def float_to_apot(x, levels, indices, alpha):
    # clip values based on alpha
    if x < -alpha:
        return -alpha
    elif x > alpha:
        return alpha

    levels_lst = list(levels)
    indices_lst = list(indices)

    min_delta = math.inf
    best_idx = 0

    for level, idx in zip(levels_lst, indices_lst):
        cur_delta = abs(level - x)
        if cur_delta < min_delta:
            min_delta = cur_delta
            best_idx = idx

    return best_idx

r"""Converts floating point input into
    reduced precision floating point value
    based on quantization levels
"""
def quant_dequant_util(x, levels, indices):
    levels_lst = list(levels)
    indices_lst = list(indices)

    min_delta = math.inf
    best_fp = 0.0

    for level, idx in zip(levels_lst, indices_lst):
        cur_delta = abs(level - x)
        if cur_delta < min_delta:
            min_delta = cur_delta
            best_fp = level

    return best_fp

r"""Converts APoT input into floating point number
based on quantization levels
"""
def apot_to_float(x_apot, levels, indices):
    idx = list(indices).index(x_apot)
    return levels[idx]