Questions tagged [numpy]
NumPy is the fundamental package for scientific computing with the programming language Python.
533
questions
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1answer
66 views
Simple Genetic Algorithm in Python
For past few months I was trying to understand genetic algorithms (GA) and most of the materials availble in the web was not always easy for me. Then I came across this article written by Ahmed Gad ...
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0answers
38 views
find the maximum substring of the list make it faster
Let's say I have:
e = [1, 1, 9, 3, 7, 6, 5, 10]
k = 4
Find the maximum sum of 4 substrings without changing the order
example: ...
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vote
2answers
51 views
Is there a way to make reshaping arrays shorter and cleaner?
I'm trying to reshape my input arrays in a way that's described below to be able to fit a curve on the data points, plot it, etc.
It works fine, but I'm afraid it's not the most efficient way of ...
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2answers
125 views
Is it worth to compromise on speed to follow PEP 8 guidelines? [closed]
I have this long line of code:
enc = encoder.predict(np.array([data[stock][4*i:4*(i+30)] for i in range(lens[stock]+days-30)]))
The problem is, the number of ...
4
votes
3answers
125 views
Fast way to calculate source response using Green's function
I am a newbie in the scientific computing in python. The function I am trying to calculate is the response of the wave equation for a given source term (For reference, See: Equation 11.67 in https://...
4
votes
1answer
123 views
Cython functions for generating NumPy date ranges
I have rewritten my python code in cython in order to speed up it quite a bit. However after checking the code in jupyter it seems that part of it is still compiled as python code, therefore its not ...
2
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0answers
46 views
Python - How to efficiently bin multiple dependent variables to a common independent variable?
Setup: I have ~30 parameters (dependent variables) measured simultaneously along a common time axis with ~1Hz resolution (independent variable). I need to calculate bin averages for all parameters, ...
5
votes
1answer
45 views
Schelling's model of Segregation Python implementation with Geopandas
If you don't know what is Schelling's model of segregation, you can read it here.
The Schelling model of segregation is an agent-based model that illustrates how individual tendencies regarding ...
0
votes
2answers
58 views
Read coordinates from many files and calculate polygon areas
My goal with this snippet is to create an array of coordinates which in turn is a tuple of 68 elements, area and modified area array for all 10k elements and assign it to the ...
2
votes
1answer
74 views
Game of life using NumPy
I'm trying to improve my Game of life program for school in Python, to be able to run it quicker. So if you have some ideas, I will be glad to hear them.
My current code:
...
8
votes
1answer
146 views
Bilinear image interpolation
I have written a bilinear interpolant, which is working moderately well except that is painfuly slow. How can rewrite the code to make it faster? Using opencv directly isn't a valid answer.
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votes
2answers
65 views
Grouping sorted coordinates based on proximity to each other
I created an algotrithm that groups a sorted list of coordinates into buckets based on their proximity (30) to one another.
Steps:
Create a new key with a list ...
4
votes
1answer
84 views
Evaluate joint probability density function of a Markov random field
The following code evaluates probability mass function for all possible states of a model.
...
3
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2answers
91 views
Find the next predicted time a satellite is going to take picture of place
create a function which predicts the next time a satellite image will be taken of a certain location.
When there is enough data to do so, the function should print a prediction for when the next ...
3
votes
1answer
62 views
Hurst Exponent calculator
I am aiming to compute the Hurst Exponent of a 1-D signal time series in Python. For now, I have one existing function hurst(sig) which returns the Hurst exponent ...
3
votes
1answer
39 views
Converting string of hex values to numpy array of specific shape
I am working on a project that needs to take a .bdf font file and turn it into a Numpy array. I am using the code below to turn the bitmap for the font into a numpy array. It currently works, I just ...
2
votes
1answer
52 views
Trapezoidal rule for set of data
Here is the question from the book of Mark Newman-Computational Physics Exc 5.1
a) Read in the data and, using the trapezoidal rule, calculate from them the approximate distance traveled by the ...
3
votes
2answers
97 views
Calculate mean and standard error of a generator in Python
The goal of the following code is to calculate the mean and the standard error of vectors of randomly-generated numbers. I am looking for feedback both on the correctness of the calculation, and on ...
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0answers
28 views
Parsing and plotting with numpy (or pandas)
I am trying to improve the following code to make it more broadly applicable and quick to use.
...
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2answers
111 views
Performance issues with double for loops, EM-algorithm
The alpha that I create is not created in a crazily efficient way I know, but the main bottleneck in this code is in what I call the "Maximization step" (see comments in code). There are double for-...
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1answer
79 views
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1answer
52 views
Nested list performance tuning
I need to make a function like these two, but at least an order of magnitude faster in python.
Any tips or tricks?
These functions inputs are nested lists, like: ...
7
votes
1answer
87 views
Generating Latin hypercube samples with numpy
I wrote some code to generate Latin hypercube samples for interpolation over high-dimensional parameter spaces. Latin hypercubes are essentially collections of points on a hypercube that are placed on ...
9
votes
3answers
916 views
KenKen solver - Python
Here is my code for the KenKen puzzle:
The user must fill in each embolded regions with numbers in the range 1-n where n is the board dimensions (e.g: 4*4, n=4) ...
4
votes
1answer
92 views
Agent based model in Python
My model is based on the Ultimatum Game. I won't go into the intuition behind it but generally speaking it functions as follows:
The game consists of a n × n lattice on which an agent is placed at ...
3
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0answers
37 views
Implementing a tic tac toe board in python
This is my attempt at making a class to represent a game board for tic tac toe. I normally hate while loops but I used one because I cant seem to make the ...
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0answers
34 views
Sortings stocks into quantiles based on their signal
This function sorts stocks into quantiles.
To do so I used this function that accepts sig_df (dataframe with the timeseries of stocks signal) and number of ...
2
votes
1answer
50 views
Grid class for games using python
I made this class to eventually create a tic tac toe game. I used numpy which is a first for me. Here it is:
...
2
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1answer
40 views
Efficient resampling of time series
I'm trying to create an efficient function for re-sampling time-series data.
Assumption: Both sets of time-series data have the same start and end time. (I do this in a separate step.)
Resample ...
5
votes
1answer
73 views
Pad a ragged multidimensional array to rectangular shape
For some machine learning purpose, I need to work with sequences with different lengths. To be able to process efficiently those sequences, I need to process them in batches of size ...
6
votes
2answers
142 views
Positive cumulative sum of difference
I have a water reservoir with input and output rates. I want to determine when the input is exceeding the output by a certain constant. To accomplish this, I need to cumulatively sum all cases where ...
2
votes
1answer
50 views
Select optimal piecewise regression fit
I'm making a program which fits a piecewise linear regression with up to 4-5 breakpoints in the data, and then deciding how many breakpoints is best to prevent over and underfitting. However, my code ...
5
votes
3answers
146 views
Python solution for the N-Queens challenge
Here is my coded solution for the N-queens challenge
The n-queens puzzle is the problem of placing n queens on an n×n chessboard such that no two queens attack each other.
The program outputs all ...
3
votes
0answers
65 views
Optimising Probabilistic Weighted Moving Average (PEWMA) df.iterrows loop in Pandas
I'm implementing the Probabilistic Exponentially Weighted Mean for real time prediction of sensor data in pandas but have issues with optimising the pandas notebook for quick iterations.
Is there a ...
6
votes
1answer
99 views
Choosing evenly distributed points from a million points on a sphere
I have \$10^5\$ to \$10^6\$ points on a sphere, and want to choose some points from them which are as close as uniformly distributed as possible. For that reason, I do the following: at each step I ...
4
votes
1answer
65 views
Gravity simulation using Numpy and Pygame
This is a simple gravity simulator coded in Python 3.7 using Numpy and Pygame. I was wondering if it can be optimized further. Initially I had coded it using pure Python lists, using nested loops to ...
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0answers
66 views
Numerical integration in cython
I have a set of nested functions that I need to call multiple times. I know scipy.quad is pretty fast, but I will need to call the integrator recursively and want ...
7
votes
0answers
61 views
Find indices using for loop
I should estimate the effect of B fields on particle deflection using \$F=V \times B \times Force\$.
I have a 2D mesh with \$n_x\$ and \$n_y\$ which show the number of points in each direction. \$B\$ ...
2
votes
0answers
47 views
Python list operation - merge adjacent cubes into minimum number of shapes
I am hoping to find a way to make the process a lot faster. The lists are made of rows of 6 numbers, i.e. [[float] * 6, ...]. The intent is to pass a list of cube ...
3
votes
2answers
93 views
3D metrics for segmentation evaluation
I am new to programming and I am trying to develop a machine learning approach for image segmentation (https://en.wikipedia.org/wiki/Image_segmentation) and here I want to evaluate the predicted (...
2
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0answers
61 views
Extract cell values from multiband rasters
I have the following function and code snippet to extract cell values for multiple years, format it, and save to a list. Each raster has 365 bands — one for each day. A separate operation is performed ...
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0answers
174 views
Population dynamic simulation on biological information maintenance 2
This question is the follow-up to this previous question.
Background
Using this simulation I investigate a system in which enzymes proliferate in cells. During the replications of enzymes, ...
4
votes
1answer
59 views
U-Net: A TensorFlow model
What I want to know
I am writing a ML model called U-Net with Python (and TensorFlow). My question is not about the machine learning or Tensorflow, I want to know the best structure of the code.
I ...
9
votes
1answer
155 views
Population dynamic simulation on biological information maintenance
Background
Using this simulation I investigate a system in which enzymes proliferate in cells. During the replications of enzymes, parasites can come to be due to mutation. They can drive the system ...
5
votes
2answers
81 views
Birthday paradox simulation
I'm writing a simulator which checks how many balls we need to occupy every box or how many balls we need for any box has at least 2 balls (birthday paradox). I wrote the script in python and it is so ...
5
votes
2answers
198 views
Improve Performance of Comparing two Numpy Arrays
I had a code challenge for a class I'm taking that built a NN algorithm. I got it to work but I used really basic methods for solving it. There are two 1D NP Arrays that have values 0-2 in them, ...
6
votes
1answer
118 views
Longest carbon chain
My Code measures the longest path, not allowing cycles. For the example input below, the longest chain would be 4
Please can you review my code?
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7
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1answer
206 views
Deep Neural Net implementation in Python3
I created my first implementation of an arbitrary feed forward neural network with a simple back-propagation training implementation.
...
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0answers
107 views
Cubic spline interpolation in Python from scratch
I implemented the cubic spline interpolation explained in
https://en.wikipedia.org/wiki/Spline_interpolation as a Python class. Of course, such an interpolation should exist already in some Python ...
3
votes
0answers
23 views
TensorFlow regressor to predict probability of winning, given a current score
This is a TensorFlow regressor that tells me that if you get x score, you will have x% to win a game in x game(game is not important).
Doing this as a project to learn tensorflow.
...
