NumPy is the fundamental package for scientific computing with the programming language Python.

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Resource-constrained project scheduling

I'm trying to implement an algorithm for a resource-constrained project scheduling problem. I have several resources, resource constraints and all of this is in ...
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18 views

Optimize Python script for generating Point Cloud

I'm trying to produce a 3D point cloud from a depth image and some camera intrinsics. The image is 640x480, and is a NumPy array of bytes. The output is a (rows * columns) x 3 array of points. I've ...
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1answer
27 views

Modeling and plotting neuron responses

I want to assign the row of a matrix the return value of a function, but the only way I can figure out how to do this is with a for-loop. I'm assuming this is bad ...
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1answer
33 views

Moving window with complete boundary in Python

I asked this question a few days ago. The question is about producing moving/rolling windows of an array in Python as in the following example: ...
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2answers
55 views

Generate random unit vectors around circle

I'm trying to generate a bunch of uniformly distributed unit vectors around the unit circle. Here's my code, which is working, but unfortunately I have a for-loop. How do I get rid of this for-loop? ...
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1answer
61 views

Iterate over coordinates and correct constraint violations

I am creating an algorithm to take a series of labelled points placed randomly and move them until they fulfil a set of constraints. The constraints have been pre-computed and are each a lower and ...
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308 views

Calculating the volume of a tetrahedron

Here's my function for calculating the volume of a tetrahedron. I've tried to comment well and perform a few checks on the types of the objects passed to it. Can ...
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1answer
65 views

Confidence score calculation

I was looking for a way to calculate a score 'x' for each pair of elements in two separate arrays. The goal of the code is to return an output array containing the score for each entry in the input ...
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1answer
73 views

Look up parameters based on a numpy array of input values

Aim: Write a function that looks up empirical parameters A, B and C for a solar radiation ...
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1answer
130 views

Harmonic analysis of time series applied to arrays

I've developed some code in Python to apply a harmonic analysis of timeseries (for satellite imagery data). It's based on this, but then I would like to optimize the performance. So instead of a ...
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2answers
48 views

Scoring system of a pool of dice

I want to do some Monte Carlo simulations on a system based on a pool of dice. For each trial, a number of dies are rolled, and the winner is the highest value, getting as many points as dice are over ...
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1answer
126 views

Intersection between arrays

I'm a Python beginner (more used to code in R) and I'd like to optimize a function. 2 arrays ares filled by integers from 0 to 100. A number can't appear twice in a row and they're stored in an ...
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1answer
31 views

Printer Color Templates

I'm new to Python and I just wrote my first program with OOP. The program works just fine and gives me what I want. Is the code clear? Can you review the style or anything else? ...
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1answer
41 views

Improving excution time for list and sampling in Python

Here is my code for generating edge list based on Price model algorithm. I think there have two points to reduce execution time: use proper data type use faster random sampling Originally, I used ...
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80 views

Where's the bottleneck in this tvtropes.org scraper?

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1answer
97 views

Generate sample coordinates inside a Polygon

I have a Polygon named as poly. I attempted to randomly select 5 coordinate points that lies inside the polygon. ...
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56 views

Fastest computation of N likelihoods on normal distributions

In the context of a Gibbs sampler, I profiled my code and my major bottleneck is the following: I need to compute the likelihood of N points assuming they have been drawn from N normal distributions ...
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2answers
127 views

Sieve of Erathosthenes speedup

While reading HackerNews, I learned about a data set of the first 50 million primes. This would be a lot, but his website has disclaimer: n this directory I have the first fifty million primes in ...
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1answer
76 views

Calculating the distance squared between all vertex-pairs of a number of 2D polygons

I have implemented my code using Cython. It is the current bottleneck in my computations. There are two non-numpy functions involved: calculate_2D_dist_squared ...
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1answer
113 views

Speed up a function using NumPy

I have a function written in Python 2.7 that I call several times in a program. This function is rather slow, and I'd like to rewrite it in NumPy. However, I don't know how to do it. I basically have ...
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59 views

Find binary sequence in NumPy binary array

As part of creating a software defined receiver and decoder, I want to find sync pulses in weather satellite data. The data is first digitized to a 0-1 array. The code below is working. The ...
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2answers
114 views

Extracting maximum values from each of the subsets of an array

Problem description: I have a numpy array cps from which I want to extract the maximum value in each of the subsets of the array (a subset is defined as non-zero ...
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1answer
116 views

Python implementation of multidimensional power spectral density with Welch method

I have done my best to write Welch method implementation for python for multidimensional time series and still in the case of one dimensional time series I am getting inconsistent response compared to ...
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1answer
69 views

Bernoulli trials using a condition in a vectorized operation

I was wondering how to vectorize the following code instead of using the for-loop and still be able to check for a condition. ...
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1answer
70 views

Optimizing a loop for catalogue manipulation

I have a catalogue of 56000 objects and I want to replace some columns with new values for instance replace NaN with -99 and ...
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1answer
43 views

List of lists of arrays, zipping, modifying in place

I came back to some old code today and freaked out. I was like "How does this even work, and if it works it can't do what I intended." I ran a few quick tests and confirmed it did actually do what ...
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1answer
61 views

Averaging a list of intersecting rectangles

I have a list of rectangles as tuples (x, y, w, h). I need to find which ones intersect and if they do, average all the intersecting rectangles into a new rectangle. I also track the resultant ...
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111 views

Monte Carlo estimation of the Hypergeometric Function

I am trying to implement the algorithm described in the paper Statistical Test for the Comparison of Samples from Mutational Spectra (Adams & Skopek, 1986) DOI: 10.1016/0022-2836(87)90669-3: $$p ...
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1answer
237 views

K-Mean with Numpy

I have implemented the K-Mean clustering Algorithm in Numpy: ...
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1answer
306 views

Groupby in NumPy

To avoid the XY problem, here is an example of what I need. Given the sorted integer input array [1 1 1 2 2 3], I would like to produce the following slices, ...
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1answer
49 views

Stable partition in Numpy

In essence, I need to do a stable partition: All elements of the 1D np.array a that are present in ...
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1answer
91 views

Where is the bottleneck in my Cython code?

The profile tells me it took ~15s to run, but without telling me more. ...
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1answer
97 views

Neighbours from point connections

I am working with a mesh of triangles (in 3D, although I doubt it makes a difference). The mesh is given as list of lists, each list containing the indices of the three vertices of a triangle in said ...
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139 views

Parallelizing some model fitting code using multiprocessing

I'm trying to refactor some code for fitting parametric models that are defined symbolically using Theano. My goal is for all models to expose a common interface so that, as far as possible, they can ...
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1answer
82 views

How can I make this implementation of Euler's method more efficient?

I have an implementation of an Euler method for solving N-many 1st order coupled differential equations, but I feel that I did not write it as efficiently as I could, due to lack of programming ...
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37 views

Function that transforms input file based on a numpy poly1d function

I have written a function that gets a function as input (acquired from numpy.poly1d). The function has access to the GUI variables ...
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2answers
96 views

Optimization/speed up of reduction function

I'm working on an implementation of Rainbow tables as part of a project. I understand the main principles behind it had have a working solution. Unfortunately the reduction function portion of my ...
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1answer
139 views

Interpolate then maximize

I need to optimize $$ \max_{a',\ m'} f(a, m, e, m', a') $$ I have approximated \$f\$ with a grid \$F\$ — it has shape \$(nA, nM, nE, nM, nA)\$. Now, I want to interpolate over the last two ...
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82 views

Calculating mesh centers runs very slowly

I have a piece of code that is used to calculate the cell centers in a rectangular mesh. The mesh size is pretty large (650 columns by 1150 rows). The code runs very slowly. I was wondering if I could ...
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1answer
51 views

Hints to make Sukoku solver more Pythonic (II)

I tried to implement as many changes suggested as possible as well as expanding the code base according to the suggested link. The original question can be found here. It does solve Sudokus gives ...
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1answer
432 views

Hints to make Sudoku solver more Pythonic

As you will see, I am not very familiar with Python and NumPy but want to learn it. The following code is a very basic Sudoku solver which works fine for simple examples. Although it runs, I still ...
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1answer
385 views

Fixed point iteration and cobweb plot

I'm using Python to find fixed points of a given function and then draw a cobweb plot to visualize it. Thanks to this question, I have the core of the code written and can accomplish the task, but I ...
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2answers
479 views

Connect 4 game for AI agents

This Connect 4 game will be used for implementing game-playing AI. Sample players are supplied. One takes user input, and the other plays randomly. Right now it's set for a human player to play ...
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1answer
769 views

Efficient numpy cosine distance calculation

I want to calculate the nearest cosine neighbors of a vector using the rows of a matrix, and have been testing the performance of a few Python functions for doing this. ...
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1answer
332 views

Flood fill algorithm

I am implementing a flood fill algorithm using Python and NumPy. I have written the following fill function which works fine: ...
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1answer
323 views

Calculating the distance between one point, and many others

In my program, I have entities that I call "blobs", because they have a blobby shape. Blobs are polygons. If I have two blobs, then their information array would look like: ...
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238 views

Calculating if a point is within a polygon, or outside of it

Here is the function (along with its support functions): ...
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1answer
290 views

Calculating “element-wise” the angles between two lists of vectors

Let's say you have two lists of vectors: v1s = [a, b, c] v2s = [d, e, f] I am interested in generating the following ...
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2answers
83 views

Taking wind data and simulating future wind profiles

I am new to programming, and am using Python to take wind data and simulate future wind profiles. The code as written takes a while to execute and I was hoping someone could suggest ways to make my ...
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86 views

Cythonized version of FDCT (fast discrete cosine transform) function, ported from Java

This is my Cython code for an FDCT function (invoked here): ...