All Questions
2,305 questions
3
votes
0
answers
125
views
numpy.load() seems to use double the memory of the array at peak
I thought numpy.load() writes directly into the array data memory.
However, the results of the profiling functions (I profiled with memray and mprof) seems a bit strange to me...
My array is 2GB big. ...
- 476
0
votes
1
answer
67
views
Apparently weird condition on inclusion of endpoint in np.arange() [duplicate]
The numpy.arange function takes the three parameters: start, stop, step (positional args.)
The default step is 1.
Throughout my entire Numpy experience, the last element of the resultant array is not ...
5
votes
1
answer
104
views
Is there a Numpy method or function to split an array of uint64 into two arrays of uint32
Say I have an array as follows:
arr = np.asarray([1, 2, 3, 4294967296, 100], dtype=np.uint64)
I now want two arrays, one array with the lower 32 bits of every element, and one with the upper 32 bits ...
- 352
1
vote
2
answers
140
views
'numpy.ndarray' object has no attribute 'groupby'
I am trying to apply target encoding to categorical features using the category_encoders.TargetEncoder in Python. However, I keep getting the following error:
AttributeError: 'numpy.ndarray' object ...
- 13
10
votes
1
answer
609
views
Arrays of size 0 in NumPy
I need to work with arrays that can have zeros in their shapes. However, I am encountering an issue. Here's an example:
import numpy as np
arr = np.array([[]])
assert arr.shape == (1,0)
arr.reshape((...
- 2,137
2
votes
1
answer
126
views
0-dimensional array problems with `numpy.vectorize`
numpy.vectorize conveniently converts a scalar function to vectorized functions that can be applied directly to arrays. However, when inputting a single value into the vectorized function, the output ...
- 107
1
vote
0
answers
47
views
Python Numpy Crash without error or warning with exit code -1073740791 due to _multiarray_umath.cp312-win_amd64.pyd
Numpy library crash without console error or warning constantly
In Python Console see notifications either Process finished with exit code -1073741819 (0xC0000005) or Process finished with exit code -...
- 11
0
votes
1
answer
107
views
NumPy Stride Tricks: Is it possible to add the windows back into the original array size at the same location without for loops?
I'm currently trying to implement my own version of 2D Pooling (with channels included) in Python using only NumPy, but I've run into a bit of a roadblock with vectorizing the backpropagation process. ...
-1
votes
1
answer
41
views
Sort columns of numpy unitary matrix such that highest element of each column is on the diagonal
Take a unitary matrix U. I want to swap the columns such that the largest element of each column (in absolute value) is on the diagonal (modulo ties). What is the best way to do this in numpy?
- 377
0
votes
1
answer
50
views
How to get row numbers of maximum elements in a 2D Numpy array? [duplicate]
I have a 2D array a given by:
a = np.array([[2, 3, 1, 9], [0, 5, 4, 7], [2, 4, 6, 8]])
[[2 3 1 9]
[0 5 4 7]
[2 4 6 8]]
I would like to get row numbers of maximum elements column-wise, i.e. given ...
- 8,265
0
votes
1
answer
71
views
Removing rows from numpy 3D array based on last element
What I'm trying to do is essentially removing all rows h,s in a 3D numpy array a if a[h,s,v] = some value for all v
More specifically, I have a loaded image from cv2 which contains some transparent ...
- 435
1
vote
2
answers
42
views
Counting the hashtags in a collection of tweets: two methods with inconsistent results
I'm playing around with a numpy dataframe containing two columns: 'tweet_text' and 'cyberbullying_type'. It was created through this dataset as follows:
df = pd.read_csv('data/cyberbullying_tweets.csv'...
- 466
1
vote
3
answers
61
views
Have numpy.concatenate return proper subclass rather than plain ndarray
I have a numpy array subclass, and I'd like to be able to concatenate them.
import numpy as np
class BreakfastArray(np.ndarray):
def __new__(cls, n=1):
dtypes=[("waffles", int), ...
- 965
1
vote
3
answers
64
views
Can I create a multidimensional array containing a unit matrix without nested loops? [closed]
Suppose I have a Numpy array n indices, where the first n-2 represents some counting indices and the last 2 indices represent a square MxM matrix. I want to initialize this structure so it will ...
- 863
5
votes
4
answers
100
views
Slice a numpy 2d array using another 2d array
I have a 2D array of (4,5) and another 2D array of (4,2) shape. The second array contains the start and end indices that I need to filter out from first array i.e., I want to slice the first array ...
- 630