Questions about optimizing code for faster results, or how to do faster computations.
1
vote
0answers
79 views
Performance in parameter estimation from ParametricNDSolve using varied initial conditions
I have 250 data points from a timecourse exeriment in a list, with columns specifying (1) time, (2-4) initial conditions, (5) absorbance reading. I want to fit 4 parameters (k1, k2, k3, k4) in a DAE ...
23
votes
4answers
855 views
What is the fastest way to count square-free words?
Background
A word is a string of letters in an alphabet. A square-free word has no adjacent repeating substring. For example, (in the ternary alphabet of {0,1,2}) the words 00, 012121, and 0212012021 ...
3
votes
4answers
163 views
Remove linear trend from data
I have a large data set with 150k lines and two data columns. I noticed that there is a linear trend, which I want to remove. So, I do the following:
first fit with a linear model
...
1
vote
2answers
91 views
Speeding up a simple simulation with random extractions
I wonder if anybody can help, I need a hand with a simple simulation I am writing with Mathematica (I am using version 8). Basically it creates a list (called l) with numbers from 1 to n and a random ...
0
votes
1answer
87 views
Alleviating a bottleneck involving a function call with symbolic derivatives
I have a bottleneck problem involving a function call with symbolic derivatives.
I don't have much experience with Mathematica (or any dynamic language) and I'm certain that the way I've set this up ...
2
votes
0answers
121 views
Project Euler (memory and speed issues)
Let n be a positive integer. An integer triple (a, b, c) is called a factorisation triple of n if:
1 ≤ a ≤ b ≤ c
a·b·c = n.
Define f(n) to be a + b + c for the factorisation triple (a, b, c) of n ...
10
votes
1answer
360 views
Is there a simple example using OpenCLLink that shows performance advantages?
OpenCLLink allows Mathematica to use the OpenCL parallel computing language. I have done some tests on simple examples, but so far, the CPU regularly outperforms ...
2
votes
1answer
114 views
EmpiricalDistribution for Gini Coefficient Runs Slow
I am repurposing code that I found in this blog post (http://datavoreconsulting.com/sports/gini-coefficients-and-the-olympic-medal-race/) to generate the Gini coefficient for other data sets I am ...
1
vote
1answer
111 views
Speeding up code by avoiding repeated evaluation of a function
I want to speed up my code and I have two ideas, but I don't know how I can implement them.
Here is a little part of my code, which I want to improve:
...
1
vote
0answers
298 views
Speed up Numerical Integration
EDIT:
I need to evaluate a very complicated multi-dimensional Integral. The dimension of the Integral depends on a variable j. Let's make my point clear with the ...
2
votes
1answer
150 views
symbolic integration of a definite integral, how to speed up
I am wondering what are the general tips & hints for speeding up symbolic integration. As far as I understand, it solely depends on the form a function is represented before it is processed by ...
5
votes
1answer
129 views
Random number generation with specific distribution
I am writing a program for solving the shortest path in travelling salesman problem, with a twist that there are multiple salesmen who partition the cities among themselves, thus creating two part ...
6
votes
2answers
209 views
Use of Cellular Automaton or Discrete Convolution to calculate Potts Energy of a 2D Matrix
In a project of Monte Carlo Modelling of Grain Growth (Link) one of the most costly subroutines is the calculation of the Potts-Energy of an Monte Carlo Grid cell by comparing the center cell value ...
7
votes
2answers
617 views
Convolution with interpolated function
I have some problems to calculate in reasonable speed the convolution of an interpolated function with a Gauss function.
I have here (ExampleData.txt, alternate Pastebin link) data which I ...
9
votes
2answers
266 views
Fast Simulations with Compile
this post relates to another post that I didn't follow up propely. If I wanted to simulate
a system of stochastic proesses like the following, and loop over this run many many times
would writing the ...
19
votes
2answers
566 views
How to quickly calculate intersections of filled curves?
I am trying to quickly calculate the intersection of polygons with more than 6,000 points. A compiled solution would be preferable.
Here is one example of the problem:
...
14
votes
2answers
380 views
How can I speed up the classic GA for graph coloring?
I'm trying to compute the chromatic number of this graph (which is 28):
g = Import@"http://www.info.univ-angers.fr/pub/porumbel/graphs/dsjc250.5.col";
My genetic ...
6
votes
3answers
286 views
Why is AstronomicalData so slow?
I'm having trouble getting some pretty simple functions using AstronomicalData to perform at anywhere near the speed I need them to.
For example, I have many ...
4
votes
1answer
510 views
Improving NDSolve speed for heavily stiff problems
Having looked around the intergoogles and Mathematica.SE, I thought I'd pose a question with a minimum working example.
Here is the situation I am trying to improve:
I am solving a 4th order non ...
3
votes
2answers
141 views
How to speed up drawing a tangent plane?
I have this code to produce an interactive visualization of a tangent plane to a function:
...
2
votes
1answer
170 views
Why is LogLogPlot[] slower than Plot[]?
I notice that LogLogPlot runs quite bit more slowly than ordinary Plot. For example, consider the following two blocks of code ...
7
votes
3answers
201 views
How can I efficiently check if a graph is unit distance?
A unit distance graph is a graph that is embeddable in the plane so that every edge has length 1.
...
