spectral-norm Python 3 #8 program
source code
# The Computer Language Benchmarks Game
# https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
#
# Contributed by Sebastien Loisel
# Fixed by Isaac Gouy
# Sped up by Josh Goldfoot
# Dirtily sped up by Simon Descarpentries
# Used list comprehension by Vadim Zelenin
# Concurrency by Jason Stitt
# Concurrency simplified by Matt Vollrath
# Optimized math by Adam Beckmeyer
from itertools import repeat
from math import sqrt
from multiprocessing import Pool
from sys import argv
def eval_A(i, j):
ij = i + j
return ij * (ij + 1) // 2 + i + 1
def A_sum(u, i):
return sum(u_j / eval_A(i, j) for j, u_j in enumerate(u))
def At_sum(u, i):
return sum(u_j / eval_A(j, i) for j, u_j in enumerate(u))
def multiply_AtAv(u):
r = range(len(u))
tmp = pool.starmap(
A_sum,
zip(repeat(u), r)
)
return pool.starmap(
At_sum,
zip(repeat(tmp), r)
)
def main():
n = int(argv[1])
u = [1] * n
for _ in range(10):
v = multiply_AtAv(u)
u = multiply_AtAv(v)
vBv = vv = 0
for ue, ve in zip(u, v):
vBv += ue * ve
vv += ve * ve
result = sqrt(vBv/vv)
print("{0:.9f}".format(result))
if __name__ == '__main__':
with Pool(processes=4) as pool:
main()
notes, command-line, and program output
NOTES:
64-bit Ubuntu quad core
Python 3.11.1
Tue, 24 Jan 2023 21:58:23 GMT
MAKE:
mv spectralnorm.python3-8.python3 spectralnorm.python3-8.py
pyright .
No configuration file found.
No pyproject.toml file found.
stubPath /home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/typings is not a valid directory.
Assuming Python platform Linux
Searching for source files
Found 1 source file
pyright 1.1.288
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/spectralnorm.python3-8.py
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/spectralnorm.python3-8.py:56:26 - error: "v" is possibly unbound (reportUnboundVariable)
1 error, 0 warnings, 0 informations
Completed in 1.883sec
make: [/home/dunham/all-benchmarksgame/2000-benchmarksgame/nanobench/makefiles/u64q.programs.Makefile:388: spectralnorm.python3-8.python3_run] Error 1 (ignored)
3.42s to complete and log all make actions
COMMAND LINE:
/opt/src/Python-3.11.1/bin/python3 -OO spectralnorm.python3-8.py 5500
PROGRAM OUTPUT:
1.274224153