Questions tagged [parallelization]

Questions on parallel computing in Mathematica.

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Different output when using ParallelDo

I think this is a very naive question which emerges from my poor understanding of ParallelDo and parallel computation in general. Suppose, I have this simple code: <...
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1 answer
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Problem with file locking

Before reporting this to Wolfram I want to make sure that I am not mistaken. I am using MMA version 13.0.1 The following will lock a file and then write "Hello" into it, all in the current ...
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Syntax for parallel processing

I have a Do[] loop that references a few global variables but doesn't modify anything. The only output is appending data to an external file. The order of appending doesn't matter, I just can't have ...
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Parallelization of indepedent Do

I'm struggling understanding the syntax for parallel process. I have two Do that are independent and I would like to parallelize them, ...
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Why is the parallelized version so much slower here?

I evaluated the following code: spikes = Select[waveforms[[channel]], #[[2]] < thresholds[[channel]] &] and according to ...
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4 votes
1 answer
73 views

Problem with labeled functions and ParallelEvaluate [duplicate]

Bug introduced in 8 or earlier and persisting through 13.0.1 I came across behaviour of ParallelEvaluate that I do not understand. In a loop I define five ...
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Parallelize for loop in mathematica

I have the following code which essentially consists of a first for loop that iterates through a very large number of rows and a small for loop that iterates through a small number of columns. The ...
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2 votes
1 answer
119 views

Speed Up the Gelman-Rubin-History function

A bit of background information I have created a function to calculate the convergence of the Gelman Rubin diagnostic (useful in Bayesian analysis). The function seems to work as I want, however I ...
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Context problems with ParallelTable and Import/Export

I work with notebooks with contexts unique to each notebook and I want to compute a list of functions $f(z,w)$ via ParallelTable and save them to files in NotebookA ...
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3 votes
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Parallel Evaluation Stops Evaluating Without Warning Message

This is my full code ...
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5 votes
3 answers
246 views

ParallelDo barely faster than Do

I am new to parallel computing, so I am trying to get a grasp as to how this works. Many posts seem to indicate that overhead (like here) is a common pitfall, but I do not see why this would be the ...
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Parallel computing environment

In the following environment ...
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4 votes
2 answers
84 views

Limit the number of cores used

Sometimes, when Mathematica thinks it is needed, it automatically threads a computation on several cores, it can happen for NIntegrate or ...
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Vectorise IF statement

I would like to perform an iteration on a list, component-wise. The iteration is time consuming and it would be hence beneficial to be able to stop it once an element of the list has reached a ...
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How to avoid running out of memory in ParallelMap?

I am mapping a function over a list of length 77237. ParallelMap[AnalyzeZernikeRecord,records] The result of each function application is just a list of 12 numbers....
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How can I make ParallelDo faster than Do?

I am trying to optimize my code as much as possible. So first I used a compile and now I am trying to parallelize the code in order to make it faster because in the end I will need to make a loop that ...
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4 votes
1 answer
190 views

Speeding up Fourier transform and eigenvector calculation

I have a matrix $M$ in Bloch basis (momentum space). Then I have to take Fourier transform of $M$ to go to real space. The size of this lattice in real space can be fixed to some value $N_{unit}$. ...
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1 vote
2 answers
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Parallelize elements of a vector or array

Suppose I want to calculate a vector or an array (say, for simplicity a 4-by-1 vector), but each element contains independent numerically evaluated functions $f_1,f_2,f_3,f_4$ and each takes long time....
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Possible bug: Wrong differentiation of ParametricFunction inside Parallelize?

In the note RootSearch problem when called from within ParallelDo I described the problem with Ted Ersek's RootSearch package and came to the conclusion that it is ...
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1 vote
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108 views

RootSearch problem when called from within ParallelDo

I have been using Ted Ersek's RootSearch package for Wolfram Mathematica for many years. The package worked great, including inside the ...
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4 votes
1 answer
120 views

ParallelTable/ParallelDo for Newton's Method doesn't work [closed]

We run such ParallelTable based on @Syed https://mathematica.stackexchange.com/a/261603/54516. ...
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Trying to speed up finding solutions of quadratic form related to the weight of a matrix

Say I have an integer matrix of size $5 \times 5$ - I am trying to find the solutions to the equation $n^4 wtM = n w^2 + x1^2 + x2^2 +x3^2 +x4^2 + x5^2$ subject to the constraints $x1+x2+x3+x4+x5 = 0$ ...
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2 votes
0 answers
64 views

Set Default System Options

I have a new Mac M1 machine and am getting Mathematica set up on it. I noticed that when I run some simple benchmarking tests, for example matrix diagonalization, the code runs significantly slower if ...
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7 votes
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153 views

Are all MMA computations single-core unless explicitly parallelized?

I was wondering if the WolframMark Benchmark uses more than one core. This becomes relevant when comparing Benchmark scores between, say, 4-core and 8-core machines. I looked at Benchmark's code, and ...
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3 votes
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Parallel Cellprint Not Rendered

I'd like to parallelly construct cells (possibly dynamically updating ones) and output render them on the front-end. However, I found this is not working. For example, ...
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4 votes
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61 views

A WolframKernel (with PID) is created by a LocalSubmit. After the LocalSubmit finishes its job, the kernel remains. How to kill it within Mathematica?

When defining a task with LocalSubmit, a new subkernel is created. When you remove the task after the task is done, the task is removed but the subkernel remains ...
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1 answer
70 views

Parallelization in While[] loop when testing if a condition is met

Well, I am trying to run the following code: ...
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Effectively using all CPU cores while exporting a sequence of plots

In Wolfram Mathematica 12.3.1 on macOS I use Do[Export i-th plot to PNG file,{i,LargeNumber}] to generate a sequence of plots. This works well, but I noticed that ...
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Parallel Table dont use Paralization after long calculation

at first: This is my first post and I hope you understand me. If I made any mistakes how to write a question please feel free to correct me. Now to the question. I wrote a module which evaluates a ...
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What is the difference between "SessionSubmit" and "LocalSubmit" in performance?

Does SessionSubmit forward the computation to the master thread and LocalSubmit to some other idle thread? By thread, I mean CPU ...
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9 votes
2 answers
356 views

How to parallelize and speedup AppendTo? [duplicate]

Say I have a list of original data (for now generating random list as follows): ...
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0 answers
45 views

Launch remote kernels on the cluster node

I run the Mathematica front end with Xterm on main machine of Unix cluster. It can start parallel kernels locally ...
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2 votes
0 answers
51 views

Parallel kernel configuration settings missing on MacBook ARM

$Version (* 12.3.1 for Mac OS X ARM (64-bit) (July 8, 2021) *) In the preferences panel, the parallel kernel settings are missing. Evaluating ...
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1 vote
1 answer
57 views

Data parallelism for independent probabilistic trials

I'm considering the best way to implement the data parallelism features of Mathematica for a specific task. To that end I have a minimal code example below which contains the basic features of my ...
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1 vote
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90 views

Increase the speed of Machine learning based on 'Predict'

I am training a ANN model with a large dataset (~million level) using Predict or NetTrain function. I do not have a GPU machine but have a server equipped with 16 CPU cores. How can I maximize the ...
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1 answer
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Cannot retrieve a function definition from file after save with ParallelDo

This is an example of a problem I have retrieving functions from a file I save using ParalleDo. ...
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4 votes
1 answer
68 views

Why are DownValues of symbols in System` such as CircleDot not distributed to subkernels?

Consider a symbol in System such as CircleDot. I want to redefine this symbol and distribute the definition to subkernel, to use ...
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5 votes
0 answers
191 views

How to allow one process to take advantage of all available cores while other processes run in parallel?

I have to run multiple tasks simultaneously: Data download from stock exchange during live market session and append it to a global variable. Process the data by taking the data from the front of the ...
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0 answers
60 views

MathLink related error on HPC

Most of the times, Mathematica gives the following error for the jobs submitted on multiple nodes in queue: ...
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1 vote
0 answers
58 views

What do do if Mathematica stops without error messages?

I am trying to run the relatively simple code ...
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1 vote
0 answers
55 views

Is FindMinimum function multithreaded? Is it worth it to use this function in ParallelDo loop? [duplicate]

I have to call FindMinimum function n times on my data. But when I put it in ParallelDo loop it works slower than in casual Do loop. I wonder what might be the case (in the loop there are no other ...
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1 vote
0 answers
145 views

How to limit the cpu usage of Mathematica?

I am runing mathematica with ParallelMap[], on a win10 computer with 8 physical cores. The cpu usage always rocks up to 100%, though ...
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1 answer
30 views

How to create ParallelDo loop with n dimensions of evaluation?

For example if I have n=2 i get ParallelDo[something, {v[1], c[1]}, {v[2], c[2]}] and if I have n=3 I get ...
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3 votes
1 answer
306 views

Why ParallelTable is even slower than Table for large tensor construction?

I would like to create a large rank-4 tensor by using both Table and ParallelTable. What is actually constructed is given below: ...
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2 votes
0 answers
121 views

Want to revert back from version 12.3 to 12.1 but kernels no longer run in 12.1 [closed]

I upgraded from 12.1 to 12.3 and then Mathematica began randomly crashing intermittently. It's not reproducible: it crashed when I was rotating a 3D plot twice, crashed once when I tried to save a ...
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4 votes
1 answer
122 views

How can I reduce the memory cost of this parallel table?

The main question I was trying to obtain the piecewise cubic-spline interpolating polynomials of a series of very long lists of (x, f(x)) pairs (O(100) of them with length ~350,000), i.e. to get ...
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1 vote
0 answers
33 views

Running ParallelTable[] with ssh

I have a ParallelTable[] code, that runs perfectly fine on my local machine, but to speed things up a notch, I want to run it on a remote server. I configured everything in Evaluation>> Parallel ...
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2 votes
1 answer
84 views

Considerations for Compiling and Parallelizing Code Outside or Inside Map[]

Assume f as well as Map[f,list] are parallelizable and compilable, such that parallelization and compilation give significant ...
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0 votes
0 answers
57 views

parallelization works only with one kernel

I am using MMA 12.3.1 on Ubuntu 18.04, and my license support parallelization. The default kernel is Local and I create another one named newKernel. when I launch MMA and choose Local to perform some ...
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1 vote
0 answers
38 views

Should I use `ParallelNeeds` or `DistributedContexts`?

According to Mathematica documentation, ParallelNeeds can load packages for all kernels, while parallelized functions like ...
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