spectral-norm Python 3 #6 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
# 2to3

from math      import sqrt
from sys       import argv

def eval_A(i, j):
ij = i+j
return 1.0 / (ij * (ij + 1) / 2 + i + 1)

def eval_A_times_u(u):
local_eval_A = eval_A

return [ sum([ local_eval_A(i, j) * u_j
for j, u_j in enumerate(u)
]
)
for i in range(len(u))
]

def eval_At_times_u(u):
local_eval_A = eval_A

return [ sum([ local_eval_A(j, i) * u_j
for j, u_j in enumerate(u)
]
)
for i in range(len(u))
]

def eval_AtA_times_u(u):
return eval_At_times_u(eval_A_times_u(u))

def main():
n = int(argv[1])
u = [1] * n
local_eval_AtA_times_u = eval_AtA_times_u

for dummy in range(10):
v = local_eval_AtA_times_u(u)
u = local_eval_AtA_times_u(v)

vBv = vv = 0

for ue, ve in zip(u, v):
vBv += ue * ve
vv  += ve * ve

print("%0.9f" % (sqrt(vBv/vv)))

main()
```

notes, command-line, and program output

```NOTES:
Python 3.12.3

Tue, 28 May 2024 01:30:34 GMT

MAKE:
mv spectralnorm.python3-6.python3 spectralnorm.python3-6.py
pyright .
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/spectralnorm.python3-6.py
/home/dunham/all-benchmarksgame/benchmarksgame_i53330/spectralnorm/tmp/spectralnorm.python3-6.py:57:26 - error: "v" is possibly unbound (reportPossiblyUnboundVariable)
1 error, 0 warnings, 0 informations
make: [/home/dunham/all-benchmarksgame/2000-benchmarksgame/nanobench/makefiles/u64q.programs.Makefile:421: spectralnorm.python3-6.python3_run] Error 1 (ignored)

3.77s to complete and log all make actions

COMMAND LINE:
/opt/src/Python-3.12.3/bin/python3 -OO spectralnorm.python3-6.py 5500

PROGRAM OUTPUT:
1.274224153
```