When importing sklearn datasets eg. I get the error I am not sure why I get this I don’t get this error when running things from a jupyter notebook, which is also weird. Any help on this issue would be greatly appreciated Answer I figured this out. The answer is that the file I was running was named num…
Tag: numpy
Finding the index of minimum value in a row in numpy array
I can’t seem to get my head around how to do this – I am new to Python and this kind of work with arrays. I have a large array, say: I would like to find the column index of the minimum value in each row. For instance for the first 3 rows would give [2, 4, 3….]. I have
How to guess the numerical Solution for Mathieu’s Equation
am trying to predict the exact solution for the mathieu’s equation y”+(lambda – 2qcos(2x))y = 0. I have been able to get five eigenvalues for the equation using numerical approximation and I want to find for each eigenvalues a guessed exact solution. I would be greatfull if someone helps. Th…
Python / numpy: Remove empty (zeroes) border of 3D array
I have a 3D numpy array. This can be thought of as an image (to be exact it’s values of field points). I want to remove the border (0 values, note that there are negative values possible) in all dimensions. The restriction is that the dimension remains the same for all molecules, eg. I only want to remo…
Calculate the euclidian distance between an array of points to a line segment in Python without for loop
I’m looking for a function to compute the euclidian distance between a numpy array of points with two coordinates (x, y) and a line segment. My goal is to have a result in under 0.01 sec for a line segment and 10k points. I already found a function for a single point. But running a for loop is very inef…
Getting indices of ascending order of list
I know that this question has been asked a hundred times, but the answer always seems to be “use numpy’s argsort”. But either I am misinterpreting what most people are asking, or the answers are not correct for the question. Whatever be the case, I wish to get indices of a list’s ascen…
What is the advantage of saving `.npz` files instead of `.npy` in python, regarding speed, memory and look-up?
The python documentation for the numpy.savez which saves an .npz file is: The .npz file format is a zipped archive of files named after the variables they contain. The archive is not compressed and each file in the archive contains one variable in .npy format. […] When opening the saved .npz file with l…
NumPy Error: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
I am working on an Image Convolution code using numpy: I get the below error: on line while i < imax and delta_new > epsilon**2 * delta_0: Could anyone please tell me what am I doing wrong ? Answer It looks like delta_new and delta_0 are Numpy arrays, and Numpy doesn’t know how to compare them. As…
Change np.seterr behavior inside a function only
I want to change the floating point error handling of numpy inside of a single function. Typical example: I would like the call to fto not change the output of np.seterr(), I have no idea how to do this. Thanks for any help ! Answer Use the numpy.errstate context manager to change floating-point error handlin…
How to move a column in a pandas dataframe
I want to take a column indexed ‘length’ and make it my second column. It currently exists as the 5th column. I have tried: I see the following error: TypeError: must be str, not list I’m not sure how to interpret this error because it actually should be a list, right? Also, is there a gener…