Given the code snippet: where A is a CSR scipy sparse matrix, M and T are two numpy arrays. Question: During the matrix operations, does numpy treat A as a dense matrix, or M and T as two sparse matrices? I suspect that the latter case is true since the resulting matrix B is not in the sparse format. I
Tag: scipy
What are ‘population energies’?
In scipy.optimize.differential_evolution, the convergence criteria are that: This begs the question, what are ‘population energies’ please? This could be a follow up question to: Explain the intuition for the tol paramer in scipy differential evolution I tried looking in the code, but I got: So a …
Smoothing Categorical Output
I have a list of outputs obtained from a cow behavior detection model. Even in a video when a cow is laying, often time it identifies as standing and vice versa. In each video frame, a classification result is given by the model and we are appending it into a list. Let’s assume after 20 frames, we have …
PyCall can’t find scipy in Julia
I’m currently rewriting a bunch of matlab code into julia. These codes envolves a lot of math and, particularly, interpolation functions for a 3D mesh. It is easy to deal with this in matlab: all I need to do is to use interp3 function. Once I coundn’t find any simple way to do similar in Julia, I…
Butterworth filters look very strange as increasing order
I’m trying to design a simple Butterworth bandpass filter in SciPy, and I’m running into some strange results. This is giving strange results, as can be seen from the image below (Butterworth filters from order 1-10). I thought the filter was supposed to become increasingly rectangular as the orde…
How to save Python 1D, 2D or 3D NumpPy array into MATLAB .mat
Python’s SciPy package has a function that saves Python variable into MATLAB’s .mat file https://docs.scipy.org/doc/scipy/reference/generated/scipy.io.savemat.html However, the documentation lacks examples, and I don’t know what is the dictionary of variables it wants as an input. Say I have…
How to use scipy.optimize.fmin with a vector instead of a scalar
When using Scipy’s fmin function, I keep encountering the error message: ValueError: setting an array element with a sequence I have seen that this question has been asked already some times, and I have read interesting posts such as: ValueError: setting an array element with a sequence Scipy optimize f…
Why is ‘scipy.sparse.linalg.spilu’ less efficient than ‘scipy.linalg.lu’ for sparse matrix?
I posted this question on https://scicomp.stackexchange.com, but received no attention. As long as I get answer in one of them, I will inform in the other. I have a matrix B which is sparse and try to utilize a function scipy.sparse.linalg.spilu specialized for sparse matrix to factorize B. Could you please e…
How to plot the graph obtained after using solve_ivp from scipy package to solve a set of differential equations in python
I’m using solve_ivp in python to solve a set of differential equations in state-space form.My code is as follows: It shows error while using the normal plt.plot(t,X) command. How do I plot the graph between X and t? Please help Answer It’s a bit unclear what’s being calculated here, but chec…
how to perform a backwards correlation/convolution in python
I am trying to perform a backwards correlation (at least that’s what I think it’s called) on 2 matrices to get a resultant matrix. Note: backwards convolution works too, because I’m applying this to a CNN. I have the following two matrices: vals: w0: I essentially want to apply a sliding win…