I’m trying to understand how the Multiple Line Regression works in code for machine learning. The issue I’m having is that I don’t get how to set up my regression line properly or if my coefficients are correct. So I guess I can divide my thoughts into three questions. Is my method of findin…
Tag: numpy
Why does numpy.where() give two arrays with an array of more than 1 row as input?
I understand the output of np.where() with input of a one-row array. However, when a two-row array was used as an input, I don’t understand why the output of b is two arrays. The output for a[b] makes sense. output for b: output for a[b]: Answer We require two indices to access each element in 2D array.…
Revert time averaged values to instant values with numpy
I am having a 3D field of an averaged quantity. Now I am looking for a pythonic way to revert the averaging to get instantaneous values for each time stamp. Note: The averaging is made from the beginning of the whole period. It is like rolling mean with the window size adapted to the index of the value to be
Integer overflow while calculating all possible sums of n*m matrix rows
I am using this code to compute all possible sum of a n x m matrix. The code is working absolutely fine and it is fast too when using arrays of 32-bit integers like [[777,675,888],[768,777,698]]. It is using the Numpy package. However, as soon as I use 128-bit integers or bigger, I start getting negative valu…
Why non-linear response to random values is always positive?
I’m creating a non-linear response to a series of random values from {-1, +1} using a simple Volterra kernel: With a zero mean for a(k) values I would expect r(k) to have a zero mean as well for arbitrary w values. However, I get r(k) with an always positive mean value, while a mean for a(k) behaves as …
Numpy import txt file as matrix without text lines
I have a txt file like the following, where I want to import the last column without the text so that I can do matrix vector operations with it I tried numpy.loadtxt(“path”)[1:,4] but get the following error which I assume is due to the text inside my txt file Answer Numpy loadtxt has a number of …
Python – Differential equation solver for time-dependent coefficients gives different dynamics for different time offsets
I am solving the dynamics of a system when it interacts with a pulse, which basically is solving a time-dependent differential equation. In general it works fine, but whenever I take the bandwidth of the pulse small, i.e. around unity, the solver depends on where the pulse starts t0. Let me give you the code …
Build a dask dataframe from a list of dask delayed objects
I have a list of dask delayed objects Portfolio_perfs: Each delayed object is a numpy array of length 2 I want to build the following dataframe without using dask.compute: How can I build this dask dataframe without going through dask.compute? Thank you Answer Since each delayed object is a numpy array, you a…
LSTM neural network test to predict SPY prices giving me this error after training
Error is as follows: My Code is as follows: Not sure what’s going on…. Answer Just check you train dataset, there is no Open column there, so dataset_train[‘Open’] fails: Output: Maybe you want to use dataset_train[‘Value’] instead
Converting Detectron2 instance segmentation to opencv Mat array
I am trying to get a binary image from the instance segmentation output performed using Detectron2. According to the official documentation the mask’s output format is the following: “pred_masks”: a Tensor of shape (N, H, W), masks for each detected instance. So i tried converting it to numpy: mask = ou…