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Measure time in Linux - time vs clock vs getrusage vs clock_gettime vs gettimeofday vs timespec_get?
...r, hopefully not, wall-clock?)
What is the precision of the clock? (s, ms, µs, or faster?)
After how much time does the clock wrap around? Or is there some mechanism to avoid this?
Is the clock monotonic, or will it change with changes in the system time (via NTP, time zone, daylight savings time, ...
How do you get the magnitude of a vector in Numpy?
...
In [4]: %timeit np.sqrt((a*a).sum(axis=1))
100000 loops, best of 3: 15.6 µs per loop
In [5]: %timeit np.sqrt(np.einsum('ij,ij->i',a,a))
100000 loops, best of 3: 8.71 µs per loop
or vectors:
In [5]: a = np.arange(100000)
In [6]: %timeit np.sqrt(a.dot(a))
10000 loops, best of 3: 80.8 µs p...
How to access the ith column of a NumPy multidimensional array?
.... Using the copied version is much faster:
%timeit A_c1_ref.sum() # ~248 µs
%timeit A_c1_copy.sum() # ~12.8 µs
This is due to the different number of strides mentioned before:
A_c1_ref.strides[0] # 40000 bytes
A_c1_copy.strides[0] # 4 bytes
Although it might seem that using column copies...
Rank items in an array using Python/NumPy, without sorting array twice
...)
%%timeit -n10000 -r5
x = (rankdata(l) - 1).astype(int)
>>> 128 µs ± 2.72 µs per loop (mean ± std. dev. of 5 runs, 10000 loops each)
%%timeit -n10000 -r5
a = np.array(l)
r = a.argsort().argsort()
>>> 69.1 µs ± 464 ns per loop (mean ± std. dev. of 5 runs, 10000 loops each)...
Python, compute list difference
...ange(10)
b = range(10/2)
timeit[diff(a, b)]
100000 loops, best of 3: 1.97 µs per loop
timeit[set_diff(a, b)]
100000 loops, best of 3: 2.71 µs per loop
timeit[diff_lamb_hension(a, b)]
100000 loops, best of 3: 2.1 µs per loop
timeit[diff_lamb_filter(a, b)]
100000 loops, best of 3: 3.58 µs per ...
What is the most efficient string concatenation method in python?
...ng/path/'
The contenders are
f'http://{domain}/{lang}/{path}' - 0.151 µs
'http://%s/%s/%s' % (domain, lang, path) - 0.321 µs
'http://' + domain + '/' + lang + '/' + path - 0.356 µs
''.join(('http://', domain, '/', lang, '/', path)) - 0.249 µs (notice that building a constant-length tuple i...
Drop rows with all zeros in pandas data frame
...,0,1]})
In [91]: %timeit df[(df.T != 0).any()]
1000 loops, best of 3: 686 µs per loop
In [92]: df[(df.sum(axis=1) != 0)]
Out[92]:
a b
1 0 1
2 1 0
3 1 1
In [95]: %timeit df[(df.sum(axis=1) != 0)]
1000 loops, best of 3: 495 µs per loop
In [96]: %timeit df[df.values.sum(axis=1) != 0]
1...
Numpy argsort - what is it doing?
...*2)
In [81]: %timeit using_argsort_twice(x)
100000 loops, best of 3: 3.45 µs per loop
In [79]: %timeit using_indexed_assignment(x)
100000 loops, best of 3: 4.78 µs per loop
In [80]: %timeit using_rankdata(x)
100000 loops, best of 3: 19 µs per loop
In [82]: %timeit using_digitize(x)
10000 loop...
How to truncate milliseconds off of a .NET DateTime
...nce is between 50% and about 100% depending on the runtime; net 4.7.2: 0.35µs vs 0.62 µs and core 3.1: 0.18 µs vs 0.12 µs that's micro-seconds (10^-6 seconds)
– juwens
Feb 3 at 15:55
...
How to find the statistical mode?
...ered Dec 14 '12 at 8:00
Rasmus BååthRasmus Bååth
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