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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Timing Differences

In More efficient implementation for comparing coefficient lists in a Do-loop link, george2079 posts in his first answer a piece of code that takes 352 seconds to compute. When I run this same piece ...
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2answers
122 views

Make an effective projection of matrix

To best explain my problem, I will take the following example: Consider the following matrix : ...
10
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5answers
426 views

How would you efficiently implement BinListsBy?

Let's say I have a list like this: data = {{21, "Alice"}, {27, "Bob"}, {22, "Charles"}, {34, "Dora"}, {75, "Eliza"}} containing ages and names of persons. What I ...
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0answers
80 views
3
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1answer
161 views

Optimization of power tower fractal generator [closed]

I tried to optimize the code for generating power tower fractals from here. As the author suggested, I tried to memorize the points already tested in a list. Here is my code : ...
2
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3answers
238 views

Alternative ways to AppendTo and Delete in a While loop

Is there an alternative way to do AppendTo and Delete and also replace k0 during every ...
3
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0answers
136 views

Understanding performance: graph connected components

I need to analyze directed graphs with 10M edges, 1M vertices, and 300K strongly connected components, so that the largest one contains 400K vertices. I read some explanations of Leonid Shifrin here, ...
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0answers
47 views

Expectation taking unusually long to evaluate

I am trying to evaluate an expectation, but it is taking an extremely long time although the expression itself should not be too complicated. My code is ...
10
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1answer
293 views

Poor performance from Graphics3D

I wrote a game -- 2048,Some codes are from http://blog.wolfram.com/. My codes are in notebook downloads I added code so that the game can play in 3D form, but when I play it, I find that it is too ...
0
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1answer
87 views

Help with Computation-heavy triple integration

I'm Trying to use Mathematica to symbolically integrate a function with respect to x, y, and z. For some reason, this computation either takes about, 60s and returns the input, or takes many hours ...
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4answers
385 views

Generating an Ulam spiral

An Ulam Spiral is quite an interesting construction, revealing unexpected features in the distribution of primes. Here is a related topic with one answer by Pinguin Dirk, who has provided one ...
7
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3answers
334 views

Speed up ContourPlot3D

I have two issues with the following code. (1) It executes too slowly. If I use "Speed" instead of "Quality" for PerformanceGoal, I get the speed but an undesirable delay in proper rendering of the ...
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0answers
35 views
5
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2answers
85 views

ReplaceAll performance problem: packed arrays on the LHS are unpacked when the RHS is too long

The following is one of the most mysterious performance problems I encountered and came up while extending the booleval function mentioned here. I am looking for a ...
3
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1answer
72 views

Usage of Block in Compile

When is there an advantage to using Block in Compile? For instance, if I have a multiple-step code, how do I decide which ...
27
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3answers
604 views

Are there guidelines for avoiding the unpacking of a packed array?

Packed arrays are very useful because they save memory and generally allow speedier and more efficient calculation times. If a list of data currently stored as a packed array is unpacked, it can slow ...
4
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1answer
311 views

Functional programming Style & Performance

Hello i have been spending time to convert my R tools into Mathematica Packages mainly because i like the functional programming style in Mathematica. In doing so it seems that i run into one ...
4
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3answers
492 views

Why is my solution to PE #5 so slow

I'm new to Mathematica and it was suggested to me to go through the Project Euler problems in order to learn it. However, I can't quite figure out why my solution to #5 is so slow. The problem: ...
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0answers
104 views

Are there any plans to develop Wolfram OS? [closed]

Are there any plans to develop Wolfram OS? Google has developed Chrome OS/Chromium OS dedicated to easy and fast access to the web. Valve has developed Steam OS that created primarily for playing ...
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0answers
110 views

How to tweak the following purely numerical code

I am using the following numerical function in my program and I would like to speed it up. ...
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2answers
202 views

A fast way to compare interval

I have a list of intervall. Some of these intervals are disjoint, some are overlapped and some are included in others. To leave no ambiguity about my explanation, you can see the following examples: ...
2
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1answer
97 views

Randomly generated polymer with certain spatial density

For simplicity's sake, let the polymer's composing particle be integer 3-tuples (on 3D Cartesian grid), such that: Polymer-ness -- for all particle there is an directly adjacent neighbor. i.e in ...
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0answers
38 views

can I evaluate multiple cells at the same time? [duplicate]

my laptop has 2 cores, can I assign a core to evaluate one code, and the other core for another code in parallel instead of evaluating in sequence? thanks
0
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1answer
98 views

Plot a solid generated by a family of surfaces

I'm trying to graph a series of planes as a solid object in Mathematica. I first tried to use the Plot3D options as well as the fill options to plot a $3D$ volume, ...
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0answers
39 views

Hashing by Equals instead of SameQ

I have some numerical code involving complex numbers representing points on a plane. Some of these are equal but not identical, ie ...
10
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0answers
113 views

Exp is slower for some number ranges

I get a hit on performance with the Exp function depending on the range of my inputs. for example, with: ...
5
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3answers
515 views

How to solve an eigensystem faster?

I have a module that I need to call 1-10 million times in my program. Currently, it is taking several hours to run so I am hoping that I can cut down some runtime with your help. ...
1
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1answer
55 views

Compose two special power series expansions

I have two functions $A(x), B(x)$, given in a special power series form: $A(x)=1-x^{2}\left(\frac{a}{10}-\sum_{k=1}^{9}b_{k}\left(\frac{(x^{2}-1)}{r}\right)^{k}\right)$ ...
6
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1answer
706 views

Hardware Performance Metrics for Mathematica

Dear Mathematica users I am looking into buying a new computer and Mathematica is one of the main applications I run. To help me assess the overwhelming welter of choice out there: I'd like to know ...
2
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3answers
188 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 ...
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2answers
481 views

Research positions of lists of varying size

I'm new to the site and I am French, so I ask your indulgence for my future mistakes in English. I would like to optimise the following code : ...
10
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2answers
544 views

Faster “stuttering” accumulate?

Given some list of arbitrary precision numbers, e.g. (actual lists are 1M+ elements long): test={0, 2, 2, 47839283, 2, 0, 0, 2, 0, 1, 2, 0} I need to accumulate ...
14
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1answer
228 views

How to create internally optimized expression for computing with high WorkingPrecision?

I have large dataset and need to fit rather complicated function on it with different values of one of its parameters (this parameter must be fixed in every fit). I use the ...
12
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3answers
345 views

Taking Top K Occurrences

Having millions of numbers in a list, I want to take top K occurrences. MMA Commonest is very slow so I write my own versions: ...
6
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0answers
174 views

Performance tuning - Explicitly set Mathematica use Nvidia GPU for rendering

I feel hesitated to ask this question, but I cannot figure out a way to increase the performance. The problem is about running this featured example on a computer with both Intel HD GPU and Nvidia ...
8
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4answers
386 views

Plotting the components of a function that returns a list in different colors without redundant evaluations of the function

I have a function f which takes a number as input, and returns a list of numbers (the length of the list is constant). f is hard ...
15
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2answers
376 views

Is there a better way to add elements to a Graphics expression repeatedly?

Consider simple example where a set of points is generated and some are displayed. ...
6
votes
1answer
101 views

Garbage collection for memoized functions on subkernels

I have a top-level function which operates on some data: findBestIntegers[data_]:=ParallelMap[optimize,data] which makes parallelized calls to an optimization ...
10
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4answers
253 views

Efficient way of identifying the indices of first occurrences

It seems to me like identifying the first occurrence of unique elements should take about the same amount of time as it takes to delete duplicates. My data sets are much larger than this (...
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1answer
131 views

Simulation code performance tuning

The following simulation takes over 20 seconds for evaluation. I have difficulty re-coding it with Nest and Map or Compile functions to make it more efficient. Can some one help with this? The ...
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0answers
60 views

Linear interpolation over 2 variables

I'm tuning a function to data over 4-5 variables using Differential Evolution. The objective function calls frequently interpolation function. I came to a point, where compiling the objective function ...
9
votes
1answer
260 views

Mathematica9: NDSolve slows down after repeated calls

I have noted that in Mathematica 9 my code, which involves a lot of calls to NDSolve, slows down considerably after some time. Apparently, the problem is NDSolve itself and it seems to be related to ...
3
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0answers
113 views

What can I do to improve the performance of my calculations?

I'm trying to express a simple probability problem in Mathematica, but am having trouble getting my calculations to execute at a reasonable speed. I have an object whose unknown location is modeled ...
9
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3answers
443 views

What is the most efficient way to map a linked list?

In order to work with lists effectively using common recursive patterns from functional programming, it's often most convenient to worked with the "linked list" representation, that looks like this: ...
4
votes
1answer
245 views

Bresenham's line algorithm

Bresenham's line algorithm is producing discretized line for given two points for purpose of plotting for example. Like that: I have to stress that I'm interested in positions, not a plot. ...
4
votes
4answers
280 views

Distance between two line segments in 3-space

I need to compute the distance between two line segments in a project. After googling, I found this algorithm and used it to implement a Mathematica version: ...
65
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2answers
737 views

Why are numeric division and subtraction not handled better in Mathematica?

There is something that has been troubling me for a while. At least in version 7, the performance of a / b and a - b is not ...
2
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0answers
57 views
2
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1answer
85 views

Performance on Binomial Deviate is slow

I hope I won't get spanked for reposting. This is related to a previous question discussed here: Performance on Multinomial Deviate is slow. but this version is simpler because it is a binomial ...