# Tagged Questions

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.

189 views

### Writing Faster Mathematica Code - Sow and Reap?

I am applying Select function to a large list called xyCoordinateCentreCircle. The dimensions of the list are: ...
31 views

### Sampling a Dirichlet Distribution efficiently

I'm sampling a DirichletDistribution like so: ...
84 views

### Mathematica Newmark Optimization

Here is my Mathematica code which implements the Newmark method to solve a equation of motion. The variable "ag" contains the accelerations from an earthquake record. Is it possible to optimize this ...
40 views

### How to speed up NDSolve?

I have a program where I need to iterate NDSolve thousands of times for different configurations of a diffusion problem. The thing is, I only need about 3 digits of accuracy. I looked thru previous ...
65 views

### Faster code for calculat in Integral include derivative

I saw this question How I can get faster I tried help that. But I can not understand. I want to write a faster code for: ...
489 views

### Particles bouncing in a 3D box

I made this Manipulate code which shows a pack of particles randomly moving inside a box. It has a huge performance issue. What should be the best way in doing ...
121 views

### RandomInteger: speed with long lists

I noticed an interesting effect with RandomInteger when looking at the time to create 10^8 random integers. The following code lines all take about 0.5 seconds on a ...
464 views

### Numerical inverse Laplace-Hankel transform

When trying to reproduce the result of this paper about numerical solution of Lamb's problem, I encountered the following double integral (to be more precise, the 0-order inverse Hankel-Laplace ...
50 views

### CompiledFunction::cfsa Argument x at position1 should be a machine-size real number [on hold]

I have a compiled function: g:=Compile[{{x, _Real}},...] and call g through an interim function: g2[x_?NumericQ] = g[x] If ...
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### unordered lists with maximum dispersion [on hold]

As you can implement the following I have a list $$L = {p1, p2, p3, p4, p5 ........ pn}, n <50$$ I need cluttering and print this list 4 ...
119 views

### Exporting a high-resolution GraphPlot of a very large graph (65,536 nodes)

Problem I have a very large graph of 65,536 vertices. GraphPlot yields: But the vertices are too dense to see in any detail, and attempting to use any of the ...
75 views

### Why are CoefficientRules and MonomialList so slow?

Why is CoefficientRules so slow in this example (v10.2 on OS X 10.11.4)? ...
56 views

### Is it better to completely forget about the existence of PowersRepresentations?

I noticed that in several cases the performance of PowersRepresentations is hugely worse than that of IntegerPartitions. (Mma ...
103 views

### Why FoldList 5 times faster than Apply for matrix multiplication?

Consider this list of $2x2$ matrices: list=RandomReal[{-2,2},{500,2,2}]; Now compare timings of Apply and ...
126 views

### Calculate the ESP Grid based on Density Grid

I want to build a fast way to convert a density grid file into a grid file of the respective electrostatic potential (ESP; also known as MEP, the molecular electrostatic potential). This ...
115 views

### Mathematica 10.X benchmark report for high-end surface pro 4/surface book?

Recently, I am seriously considering purchasing the high-end surface device (with intel i7 and maximal RAM). Mathematica will be one of the main applications. Since it is not a full or traditional ...
67 views

### NMinimize vs Simulated Annealing [closed]

Update I would find the global minima, the plotting shows that this function has many local minima. ...
109 views

### Strong glitch with Evaluate in Manipulate

I'm experiencing a strong evaluation problem for a Manipulate box and I can't find the best solution yet. Here's a MWE to show the glitch : ...
87 views

### More efficient way to generate lattice graph with edges between visible vertices?

Given a nXn lattice, I need to generate the graph such that there is an edge between two vertices iff they are directly "visible" to each other, i.e., there is no vertex between them. I'm using ...
159 views

### Why timing of FindRoot is almost the same even if the function is speedup significantly

This question is almost the same issue as this one. However, it seems that it didn't draw enough attention. Now I encountered the same problem. I previously make this post, I will copy the code here. ...
53 views

### How to speedup Plot3D with precompiled argument

I have a huge problem with my code: I estimate it to take hours to run. The scheme of the code is the following (I left the steps the same, but took much simpler functions): ...
146 views

### Efficiently importing data into Mathematica

I have a graph data file infile.txt. 3 2 0 1 1 2 3 2 0 1 2 1 3 2 1 0 1 2 3 3 0 1 1 0 1 2 3 3 0 1 1 0 2 1 3 4 0 1 1 0 1 2 2 1 ...
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### What is the good source to study advanced custom coding in Mathematica [duplicate]

My question is, probably, too general ... I deal a lot with complicated symbolic evaluations, integrations, plotting. I have troubles with optimizing my codes. They come out way too slow. Google and ...
188 views

### Fast implementation of Metropolis-Hastings update with multiple sets

This is an optimisation question rather than something I am unable to do. I have a naive, primitive working version of the code (I submit it below) but I am trying to make it work faster. I am asking ...
63 views

### Can this simple loop with several counters be improved or parallelized

I am running the following calculations. The timing for H = 2000 is about 8 days on my machine. Can this be parallelized or improved upon in some other way. Also I am trying to avoid storing the ...
329 views

### Performance of calculation of means squared displacement

How can I improve the performance of the following code which calculates the mean squared displacement for coordinates stored in data? Here for each time difference ...
3k views

### Profiling from Mathematica

I've always wished I could do some profiling like you get in Wolfram Workbench, but directly from Mathematica, without using or having Workbench. If it is possible, how can I do it?
115 views

### Is there a linter to help write good Mathematica code?

I don't do much real programming, but I've recently been turned on to Atom, which has linter plugins for over 50 languages to make coding easier (most drawing on pre-existing lint-like programs). In ...
91 views

### DatePlus and DayPlus perform much worse than my user-defined-function

I was debugging a function speed, and discovered that the time bottleneck was in DatePlus. I tried to change to DayPlus and get ...
93 views

### Speed up computation of sum from large matrix

I have a 3x3 matrix (252^3) of data (densities) and I want to compute a correlation xi from nearest neighbours as well as a sum involving a check whether the density is in a certain bin. The ...
341 views

### Give a element rank list of a list

SeedRandom[417] list1 = RandomChoice[Range[22, 28], 4] {22, 24, 26, 23} We can get the rank list ...
74 views

### Is it possible to speedup these simple linear algebra operations

I'm trying to numerically solve some equations using splitting operator method. The solver I construct iteratively constructs a matrix and feeds it to LinearSolve. ...
115 views

### How to optimize my own BezierFunction?

A few months ago, I asked a question about the implementation of Bezier surface. Please see here for a full detail. I also know that BezierFunction[] is built-in ...
86 views

### Optimization of custom probability distibutions?

Consider the two tests: Timing[Do[RandomVariate[NormalDistribution[0.5, 0.3]], {200}]] {0.001188, Null} ...
58 views

### Twin Prime Max Gaps (Performance Tuning)

Ok, let's build a foundation here: A common way of testing primality, is dividing by all primes smaller than the number's square root. For instance, $97$ is prime because dividing by none of the ...
45 views

### How to calculate a continuous function once and access values later?

I have a function that involves a numerical calculation: h[v_]:=NIntegrate[f[x]*Log[p[x, v]], {x, -Infinity, Infinity}] I need to visualize how well a bunch of ...
67 views

### Sudden changes in performance

Last week Mathematica was working fine. At the beginning of this week I went on a trip and it slowed down. I ran Needs["Benchmarking`"] BenchmarkReport[] The ...
74 views

### FourierCoefficient performance

I encountered weird performance issue while using FourierCoefficient[]. I narrowed it down to calculating $n$-th coefficient for $\cos(nx)$. ...
208 views

### Histograms of gray scale images

I have a large set of subsequent 8bit gray scale png images (50 Hz). They show the noise of a CMOS camera, with the lens covered. A subset of 50 images is available here: https://goo.gl/Sa3P9P I ...
31 views

### Performance of Apart with complex numbers

Consider the following code ...
137 views

### Fast way to evaluate the PDF of a multivariable distribution

I'm trying to evaluate the PDF of a truncated multi-normal distribution. My distribution has 8 dimensions and each value must be ≥ 0. ...
60 views

### How to compile code that involve sparse array?

I have the following code ...
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### Estimating processing time for commands

I am trying to evaluate some equations by using Taylor series of expansion (Series[], ExpandAll[], and Normal[] command), and using n equation and n unknown (Solve). Following is not full command (if ...
159 views

### How I can get faster code for computing a fractional integral?

I use of this code Fractional Integral and wrote the following code: ...
192 views

### ParallelTable behaves differently when it is run inside a package

I've been butting my head against some very weird behaviour by ParallelTable, and its interaction with packages, over the past few weeks, and making relatively ...
100 views

### Efficiently strip off coefficients in front of variables?

I am working with multivariate polynomials and need a very efficient way to decompose monomials into coefficients and pure monomials. for instance consider variables ...
76 views

### Perform matrix/tensor contractions more efficiently

Problem: explicit index contractions for matrices using the Sum command take too long, and I want to improve the performance for complicated computations. Let me ...
291 views

### What is the most efficient way to replace items in a list at periodic intervals?

For example, if I want a list of $\phi(n)$ for $1 \leq n \leq 100$ but if $n$ is a multiple of 3 I want to show a 3 instead of $\phi(n)$. I tried ...
As a part of a physics problem that I'm working on, I need to construct a rather large matrix. The matrix is a real symmetric $2^{m}\times 2^{m}$ matrix for some integer $m$, which we would like to ...