"""Benchmark for float true division tier 2 specialization.

Usage:
    ./python bench_truediv.py
"""
import timeit

N = 2_000_000
INNER = 1000


def bench(label, fn):
    iters = N // INNER
    times = [timeit.timeit(fn, number=iters) for _ in range(3)]
    t = min(times)
    print(f"  {label}: {t/N*1e9:.1f} ns/iter")


def f_chain_mul(n, a, b, c):
    t = 0.0
    for i in range(n):
        t += (a + b) * c
    return t


def f_div(n, a, b):
    t = 0.0
    for i in range(n):
        t += a / b
    return t


def f_chain_div(n, a, b, c):
    t = 0.0
    for i in range(n):
        t += (a + b) / c
    return t


def f_2px_div_y(n, x, y):
    t = 0.0
    for i in range(n):
        t += (2.0 + x) / y
    return t


def f_div_rhs(n, a, b, c):
    t = 0.0
    for i in range(n):
        t += c / (a + b)
    return t


def f_ab_div_cd(n, a, b, c, d):
    t = 0.0
    for i in range(n):
        t += (a / b) / (c / d)
    return t


def f_ab_add_cd(n, a, b, c, d):
    t = 0.0
    for i in range(n):
        t += (a / b) + (c / d)
    return t


def f_add_chain(n, a, b, c, d):
    t = 0.0
    for i in range(n):
        t += (a + b) + (c + d)
    return t


# Warmup
f_chain_mul(10000, 2.0, 3.0, 4.0)
f_div(10000, 10.0, 3.0)
f_chain_div(10000, 2.0, 3.0, 4.0)
f_2px_div_y(10000, 3.0, 4.0)
f_div_rhs(10000, 2.0, 3.0, 4.0)
f_ab_div_cd(10000, 10.0, 3.0, 4.0, 5.0)
f_ab_add_cd(10000, 10.0, 3.0, 4.0, 5.0)
f_add_chain(10000, 1.0, 2.0, 3.0, 4.0)

print("Float truediv benchmark (min of 3 runs):")
bench("(a+b) * c              (baseline) ", lambda: f_chain_mul(INNER, 2.0, 3.0, 4.0))
bench("(a+b) + (c+d)          (baseline) ", lambda: f_add_chain(INNER, 1.0, 2.0, 3.0, 4.0))
bench("a / b                  (spec div) ", lambda: f_div(INNER, 10.0, 3.0))
bench("(a+b) / c              (inplace L)", lambda: f_chain_div(INNER, 2.0, 3.0, 4.0))
bench("(2.0+x) / y            (inplace L)", lambda: f_2px_div_y(INNER, 3.0, 4.0))
bench("c / (a+b)              (inplace R)", lambda: f_div_rhs(INNER, 2.0, 3.0, 4.0))
bench("(a/b) / (c/d)          (spec div) ", lambda: f_ab_div_cd(INNER, 10.0, 3.0, 4.0, 5.0))
bench("(a/b) + (c/d)          (spec div) ", lambda: f_ab_add_cd(INNER, 10.0, 3.0, 4.0, 5.0))