Questions on optimizing Mathematica code for higher performance. This may mean faster execution, lower memory usage or both. Not to be confused with mathematical optimization.
2
votes
1answer
147 views
Why can't Mathematica parallelize this?
The following code makes mathematica print "ParallelTable::nopar1: [...] cannot be parallelized; proceeding with sequential evaluation."
...
2
votes
1answer
81 views
Optimizing a simple calculus using a list of matrices - Repeated dot product between a vector and a list of matrices [closed]
I want to make the following operation :
$$ \begin{bmatrix} \dot q_1\\\dot q_2 \end{bmatrix} + \begin{bmatrix} \begin{bmatrix} q_1 & q_2 \end{bmatrix} \mathbf A_1 \begin{bmatrix} q_1\\ q_2 ...
2
votes
1answer
196 views
using interpolation functions in ParallelMap
Edit
I am editing the question to give a simple workable example. It is at the bottom under the heading Example. The original question is now headed withe Background.
Background
I am trying to ...
2
votes
1answer
195 views
Speed up iterated manipulations of a graph / table
I am trying to generate a version of Watts' model of cascading shocks to a network following the discussion on p. 20-25 of this article.
The basic premise is to use the ...
2
votes
1answer
88 views
How can I place gui controls inside Grid? [duplicate]
In all my apps, I am facing a problem about placing the Gui controls inside Grid.
For this purpose, I wrote three functions.
The first function, ...
2
votes
0answers
51 views
Speeding up a numerical constrained quadratic optimization
I'm trying to solve a quadratic optimization problem in 35 variables, $\vec{α} = \left< α_1, \ldots, α_{35}\right>$:
$$
\begin{aligned}
&\operatorname*{maximize}_\vec{α}&&1.0\cdot ...
2
votes
0answers
114 views
MathKernel.exe capped to use only 13% of CPU?
I am using a Windows machine with 8 cores. No other process than Mathematica 8 is using CPU time right now - still the MathKernel.exe CPU usage does not go beyond 13%. My current computation takes ...
2
votes
0answers
97 views
Is there documentation on the comparative performance of Mathematica functions?
Recently I have been solving some Project Euler problems. I find there are always several ways to do the same thing. For example, one could join two lists like this:
...
2
votes
0answers
139 views
FindRoot - Speed and errors
I am using FindRoot[] to solve a complicated equation. It seems I get the correct answer even though I get errors about an ...
2
votes
1answer
236 views
Reading in Huge Text Files
I would like to read in really large text files (about 2GB) into Mathematica. The structure of the file is such that the first row and the first column are text i.e strings. Rest is all numbers. Is it ...
1
vote
2answers
149 views
What ways are there to convert an Integer to a list of digits?
How can I convert an Integer to list of numbers? For example:
781049 ==> {7, 8, 1, 0, 4, 9}
What are the possible ways of ...
1
vote
1answer
318 views
How can I speed up image importing? [closed]
The following examples show how slow it is to load a simple GIF. Can anything be done to make it faster?
System #1: Mathematica 8.0.1.0, HP notebook, Win7 64Bit, 2 x 2.4Ghz Intel Core i5, 2GB RAM, w/ ...
1
vote
1answer
101 views
how to reduce the time to calculate triple integral
i want to evaluate the following integral, but it takes 15 min to do it. i must reduce the time to calculate it, i have to do a table and create a graph, but takes too long.
anyone have an idea ?
...
1
vote
2answers
90 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 ...
1
vote
2answers
129 views
Combining lists with common elements efficiently [duplicate]
Possible Duplicate:
Computing the equivalence classes of the symmetric transitive closure of a relation
I am required to process sets consisting of 2-element subsets of integers by ...
1
vote
1answer
97 views
Understanding a slowdown associated with wrapping a set of nested Do loops with a ParallelDo expression
I have a set of set of nested Do loops that require data from three different arrays (though the position from each array is fixed per cycle of the outer Do loop). Let's call these arrays: ListA, ...
1
vote
1answer
119 views
Optimization of correlation calculation
How can I make the following line of code run faster? Is there a way to do this calculation as a matrix vs vector than vector vs vector?
In the code below, f is a ...
1
vote
1answer
122 views
Interprocedural optimization
Lets say I want to build a list of the first 1000000 primes. This is simple enough, I can just do:
AbsoluteTiming[plist = Table[Prime[i], {i, 1000000}];] and it ...
1
vote
1answer
171 views
1
vote
1answer
99 views
PDF on TransformedDistribution of two BinomialDistribution too slow
I'd been doing my own convolutions of distributions for some calculations, decided to use built-ins.
With
...
1
vote
0answers
54 views
Significant platform-dependent efficiency when importing data?
I'm curious, as I understand that answer this way:
If you are using a Linux derivative or something like cygwin on
Windows, then this is an efficient solution for reading only the third
field ...
1
vote
0answers
150 views
Faster GCD Implementation
Is there any chance to write a faster GCD than the built-in one in Mathematica?
@Mr.Wizard has written one in this question (although it's not for this purpose) which is 6 times slower on a 100k ...
1
vote
0answers
166 views
Vector computation instead of iterating over a list
I am 'Map'ping over a list. I would like to do the computation in one single iteration. Is it possible? Can 'Apply' be used here? In what way is it different from 'Map' especially in this case?
...
0
votes
1answer
189 views
How can I improve my code with efficient mathematica built-in functions?
I have written a module for my assignment like below.
V[n + 1] = rk[x[n], y[n] ,z[n], V[n]];
vs = V[n].V[n+1];
V[n + 1] =
I want to modify it with efficient ...
0
votes
3answers
75 views
Timing display of Graphics (Front End timing)
I want to know how much wall-time it takes to display a Graphics
For example this one:
...
0
votes
2answers
135 views
Fast Autocorrelation Computation
I want to compute the Autocorrelation Function (ACF) of a data table with $10^6$ entries. I know that there is a built-in function in Mathematica for that, but because I do not know how exactly it is ...
0
votes
2answers
180 views
Launching remote kernels - will it help RAM needs?
Given the exasperating RAM needs of my Mathematica program, I contemplated launching remote kernels to run my Mathematica script. This is a two part question:
Part 1
If I launch a remote kernel(s), ...
0
votes
0answers
88 views
Speeding up a for loop by removing a Sum command
I am attempting to create an array that has of order 1000 x 1000 entries. In the entry of the last column of each row, I have to carry out a sum that could contains 100s of terms (I only used 40 here ...
0
votes
0answers
84 views
Speeding up numerical computations
So, after seeing this and this post, I was thinking whether there were any general rules for speeding up numerical computations (not only NIntegrate or ...
0
votes
0answers
64 views
Complex Integration Optimization
The following code culminates in plots calculated for each value of t as given below.
I have tried compiling one of the functions and adjusting the precision of both the integration and the plotting ...
0
votes
0answers
108 views
A simple For loop visibly slowing down. Advice to fix?
I have run into a unique problem. I am going to try and describe my code and what is happening as understandably as possible.
I have a For loop that does the same set of calculations over and over ...
0
votes
0answers
138 views
Best Parallel Kernel Configuration
I wrote a code snippet which counts prime numbers in any given interval because the built-in PrimePihas a limited bounds.
...
-1
votes
1answer
61 views
Integral evaluation taking too long [closed]
When I try to evaluate the following integral, it runs for a much longer time than I think is should without producing a result. What might be the problem? Can anybody please point it out?
...
