All Questions

I created a very large 3D numpy array called tr_mat. The shape of tr_mat is: tr_mat.shape (1024, 536, 21073) Info on the 3D numpy array: First and before going into the actual code, I would like to ...

I have this function: def sort_row(row): # sums all the pixel values to find a basic pixel "brightness" value summed = np.sum(row[:, :4], axis=1) min_index = np.argmin(summed) ...

I need to generate a 2D array in python whose entries are given by a different function above and under the diagonal. I tried the following: x = np.reshape(np.logspace(0.001,10,2**12),(1,4096)) def F(...

Following on from my previous question, I am looking for an efficient implementation of a series of operations using NumPy. Problem inputs: X - An (n,2) matrix, where the second column is a ...

I was wondering what the fastest way of converting a bytestring to an array of unit8 would be in the following code? I use hashlib for SHA-256 x = hashlib.sha256(str(word).encode("ascii"))....

Is there a way to vectorize the combining of row elements with certain conditions? Conditions: Empty elements get dropped Rows with more than 1 non-empty element get delimited by '\n' Note that a) ...

I have looked around, but could not find an exact answer. I have several matrices of 1200x2000 that I want to save in a way that I can read them later in some sort of loop. When I want to save 100 of ...

I am looking for an efficient/fast method to calculate the volatility/standard deviation of several weithings/portfolios with a multi-dimensional numpy array I have a multidimensional numpy array of ...

I tried to model voxels of 3D cylinder with the following code: import math import numpy as np R0 = 500 hz = 1 x = np.arange(-1000, 1000, 1) y = np.arange(-1000, 1000, 1) z = np.arange(-10, 10, 1) ...

I have a 3D numpy array=a containing coordinates of points in space. By transforming this array through matrix operations, I got 4D numpy array, such that for each row of a there is a corresponding 3D ...

I can only find results that use tuples of coordinates to assign certain values, like this one. I want to assign values to a 2-dimensional array as a function of their coordinates. The simplest case ...

Consider the following code import timeit import numpy as np MyArray = np.empty((10000, 10000, 1)) print((MyArray.size, MyArray.shape, MyArray.dtype, np.isfortran(MyArray))) print(timeit.timeit(...

Given a ndarray of size (n, 3) with n around 1000, how to multiply together all elements for each row, fast? The (inelegant) second solution below runs in about 0.3 millisecond, can it be improved? # ...

While I was trying to understand numpy.tensordot(), I tried out the examples from the documentation and was convinced that we can get exactly same tensordoted result by different permutation of axes ...

I'm trying to compute Khatri-Rao like sum (i.e. pairwise row sum) and was able to come up with this solution: In [15]: arr1 Out[15]: array([[1, 2, 3], [2, 3, 4], [3, 4, 5]]) In [16]: ...