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.

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8
votes
0answers
98 views

How to make Graphics3D with multiple lighting sources being rendered faster

I have a very "precise"(through setting "SpherePoints") Sphere illuminated by hundreds of random color lighting sources. The ...
3
votes
3answers
263 views

fastest way to perform the following summation

I have a vector $A$ with components $A_{i}$, and two matrices $X$ and $Y$ with components $X_{ij}$, and $Y_{ij}$ respectively. What is the fastest way of performing the following summation ...
2
votes
3answers
85 views

Efficiently plotting a function with its translates?

How does one efficiently produce a plot of {f[x], f[x]+1}? Assume that f[x] is a long computation, which I would like to avoid ...
1
vote
1answer
99 views

How to rewrite a nested loop with Reap and Sow [closed]

I was wondering if anyone know how to rewrite the following nested loop but using Reap and Sow. I need to reduce the execution time. Thank you. ...
3
votes
1answer
38 views

Is it possible to generate a message when precision upgrade occur?

I use Mathematica mostly for numerical simulation, so most of the time double precision (or machine precision) is enough for me. Mathematica has this nice feature of automatically upgrade to arbitrary ...
6
votes
3answers
161 views

How to speed up the plotting of B-spline curve?

Three months ago, I asked a quesion about B-Spline basis function here, Today, I used this function to plot B-spline curve. The definition of $N_{i,p}$ ...
7
votes
1answer
213 views

Is there a faster way to Map an Association?

Consider mapping an existing Association in a manner such as this: ...
1
vote
1answer
257 views

How to implement the directed Barabasi-Albert algorithm in Mathematica?

Does anyone know how to implement an efficient version of the [directed Barabasi-Albert algorithm][1] in Mathematica that scales until hundred of thousands nodes? The directed network mechanism is ...
0
votes
0answers
76 views

How to accumulate elements in a list using Reap and Sow [duplicate]

Does anybody know how to rewrite this fragment using Reap and Sow instead of AppendTo. I need to reduce the execution time. Thank you. ...
16
votes
2answers
407 views

Why is my data 10 times slower than random data when doing matrix multiplication

I have some data generated from some program, and it appears that matrix multiplication on these data are about 10 times slower than on some random data: ...
3
votes
1answer
107 views

Making table of matrix product and efficiency

I want to make a table in which each element is a matrix product: ...
1
vote
0answers
47 views

Complex input for Compile makes it slow

I asked a question here and then tried to use Compile for the solution to gain even more speed. Inside Compile there is a loop ...
4
votes
2answers
189 views

Generate lists that satisfy a condition in an efficient way

The following code produces lists of sublists with maximum length 5 that shuffle zeros around an ordered list (here {1,2}). It produces all permutations while ...
1
vote
1answer
244 views

Lookup construction using data matrix and Reap/Sow versus AppendTo`s

I am a user of MMA9 and made my own kind of Lookup, which is now a standard command in Version 10. In my program there is a section in which by means of a StringReplace[ ]-command containing a lot of ...
4
votes
1answer
96 views

Number of divisors visualized with the QPochhammer function, how improve performance of code?

I have this code that originally is Jeffrey Stopple's code for the Riemann zeta function in the complex plane. Because I discovered yesterday that the number of divisors can be generated with the ...
1
vote
0answers
76 views

Speed up replacement using Rule Dispatch Associtation

I knew that this has asked many times, but I hope there is something more could be done to speed this up. The expression kappa is here. ...
4
votes
1answer
218 views

Fast matrix multiplication in MMA and GPU

Matlab multiplies two 3000by3000 matrix around 0.18s faster than MMA. While for just a few matrix multiplications the speed difference is not important, it becomes crucial when I want to do those ...
4
votes
1answer
154 views

Ruth-Aaron quadruple challenge

This a computational challenge, to find an efficient algorithm to discover a quadruple $(n,n+1,n+2,n+3)$ with the same sum of prime factors as described in the MO question, "Ruth-Aaron triples, etc." ...
10
votes
1answer
218 views

Max element of a list with a custom ordering function

I need a function to find max element of a list according to some custom ordering function, assuming that the function implements a total order (elements being compared might not even be numbers). ...
3
votes
2answers
454 views

Fast Trial Division

I'm going to write a custom Trial Division primality test. I know that PrimeQ will first try trial division and then switches to ...
10
votes
2answers
671 views

Rendering thousands of points

I am trying to render an image with some 120,000 Points. Technically it's just 10,000 points, plus their reflection, plus 5 rotations of both of those sets, but I'm ...
14
votes
6answers
975 views

Integers which are the sum of both two and three consecutive squares

This is a math problem I came across the other day: $365$ can be written as a sum of two and also three consecutive perfect squares: $365=14^2+13^2=12^2+11^2+10^2$ What is the next ...
5
votes
2answers
102 views

How to speed up Min of DateObjects?

I'm in version 10.0.1 using a Dataset to do some plots and things. For one of the plots I need to get the minimum date of a some filtered set of the ...
0
votes
1answer
95 views

How to speed up execution of this function?

How can I speed up the execution of following function, specifically for larger values of n? ...
4
votes
2answers
293 views

Speed up calculation

First of all thanks to: rm -rf, Mr.Wizard, Simon Woods, Pickett, Piotr Wendykier, Mac, Yves Klett, belisarius, halirutan, bill s, nikie, wxffles, ... Everybody of you helped me (a mathematica ...
4
votes
2answers
192 views

Animate skips frames and hard to control speed.

I browsed similar questions related to Animate jerkiness like here, but haven't found the right options to control animation rate while also displaying all frames: ...
2
votes
1answer
119 views

How to use slots and patterns to reduce repetitive calculation?

This is kind of complicated... How can we make MMa calculate values of a function before doing multiple pattern or slot substitutions? Answers to similar questions didn't cover the case where the ...
0
votes
1answer
69 views

Extend a function to all polynomials ( just 2 variables) when one knows its values on monomials

I need your help to make my code faster. I have a formula for computing a value from any monomial $x^i y^j$, say formular1[i_,j_]:=(Gamma[i]/Gamm[j] ). It is just ...
15
votes
2answers
250 views

A bug in Commonest in version 10

Bug introduced in 10.0.0 and fixed in 10.0.2 m_goldberg demonstrated that in Mathematica 10 Commonest does not behave as the documentation indicates that it ...
0
votes
0answers
47 views

Order of evaluation when using Solve and Minimize

I have to solve numerically an integral, that ends up being more or less as follows: Solve[f[x]==a*Sum[Sin[x-i]*(f[i]-f[i-1]),{i,1,x}],f[x]] (not actual ...
1
vote
1answer
107 views

Use Compile to speed up evaluation

I have read, that using Compile command can speed up evaluations in mathematica. I have a mathematical expression, which I evaluate using following command: ...
4
votes
1answer
104 views

Most efficient searching algorithm in a table

I am completely new in Mathematica (and in data analysis in general) and I find it really useful, although I still do not use it properly. I have the following question related to data manipulation: ...
1
vote
0answers
137 views

Best way to create symmetric matrices with block structure and additional symmetries of the submatrices

Update: you can now skip the "My attempted solution" part and jump to "My first attempt for improvement" in the end of the question. My question is related to Best way to create symmetric matrices . ...
3
votes
3answers
129 views

How to pick the maximum of a list? Improving efficiency

I need to find the element of a list, with the highest weight. Example: ...
9
votes
1answer
1k views

For loop catastrophe

I know that Mathematica prefers a functional programming way but I still have some problems for the following example. Supposing we generate a Fibonacci sequence of 10^6 elements. NestList or FoldList ...
1
vote
1answer
53 views

Performance of Extract-Transform operations

I'm doing simple data analysis. I load some date-time data from a file, it's a simple list: ...
28
votes
2answers
949 views

Can a Trie be implemented efficiently?

What is the most space and time efficient way to implement a Trie in Mathematica? Will it be practically faster than what is natively available in appropriate cases?
31
votes
1answer
582 views

Why is StringExpression faster than RegularExpression?

Edit: as noted by Albert Retey the performance difference is only seen when sub expression extraction is performed. If this test is used below the timings are similar: ...
1
vote
1answer
33 views

Generate Degeneracies in List [duplicate]

I have a list with n entries and I would like to duplicate this list p times. In my case because of the Degeneracy of my Eigenvalues. For example I have {3,2,1} and it is five-fold-degenerate so that ...
7
votes
4answers
560 views

Suppress connection to Wolfram|Alpha when making unit conversions

I want to speed up calculations with unit conversions. I suspect primarily that some units evaluate from Wolfram|Alpha. Any way to prevent this automatically, so that Mathematica throws ...
3
votes
1answer
96 views

Mathematica taking too long to calculate recursive function

I have been trying to plot those specific recursively defined functions p1 and q1 in Mathematica: ...
15
votes
1answer
319 views

Why does this line increase the consumed memory?

Probably this is a simple question, however I really don't understand this behavior in Mathematica. It particularly leads to a memory leak in a huge program I have to do processing of 3D images. I ...
4
votes
2answers
283 views

Comparing LetL and Module efficiency

I was recently introduced to the LetL macro thanks to Leonid's answer to one of my prior questions. I was, needless to say, impressed by the simplicity of its ...
5
votes
1answer
246 views

How can I Integrate large trigonometric expressions more efficiently?

I have a requirement to integrate some large symbolic expressions containing products of trigonometric functions. A single integration is averaging 7 minutes, and I have 2628 expressions to integrate, ...
1
vote
1answer
95 views

Apply functions to functions yields slow execution speed

I'm trying to write a function that parametrizes a curve c(t) by its arc length. Technicly I'm finished but if I plot the result for an example curve like ...
49
votes
2answers
10k views

How can I use Mathematica's graph functions to cheat at Boggle?

Boggle is a word game played with 16 dice and a 4x4 tray. This question is inspired by a Stack Overflow question about Boggle that I decided to solve using Mathematica. In addition to Mathematica, I ...
7
votes
1answer
65 views

Issuing user-defined messages takes a long time (Message is slow)

Issuing messages takes a very long time in version 9 and version 10. Can others reproduce this? Is there a fix? Update: This is slow only when using the front end, but not when running the kernel ...
4
votes
1answer
92 views

Slowdown of Flat attributed function

I was trying to write an associative function f using the attribute Flat. ...
16
votes
2answers
268 views

Combining images with CUDA

SMALL UPDATE: This question is left as unanswered, because none of the existing answers as of yet actually use CUDA (though, whilst being very useful). 2nd Edition: To make it a bit more clear, and ...