Questions tagged [parallelization]

Questions on parallel computing in Mathematica.

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155 views

What is the difference between controlling and computational kernels?

I have just dowloaded Mma 11.3 with a trial licence. In the download page you can see: That I can use 2 controlling kernels and 4 computing kernels. What is the difference between controlling and ...
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395 views

gridMathematica on cluster with PBS Pro

I'm running my script (say "cluster.m") on the University cluster with PBS Pro installed. The script uses simple Parallelize like this: ...
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1answer
77 views

How to understand the different output of two UnsetShared?

Update 2 In v11.0.0, situation seems getting worse. UnsetShared doesn't unshare at all. Even the code in help documentation doesn't work as expected. Update From technical support, Thank you ...
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1answer
398 views

Side effects with ParallelDo

Hi guys I've the following problem with ParallelDo: if I run the code: ...
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1answer
581 views

Why is $ProcessorCount different than the selected number of cores in PBS?

By using ParallelTable and submitting my Mathematica code to a cluster, I noticed that it was enhancing the speed even when I selected a single core in a single ...
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2answers
185 views

ParallelTable with nonstandard iterator

This works as expected: Table[x[1], {x[1], 1, 10}] However, the parallel version ParallelTable[x[1], {x[1], 1, 10}] ...
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Computers running Wolfram lightweight grid manager won't fall asleep

I have a computing environment comprised of: 27" iMac with dual cores running Mac OS X 10.6.8 and 2 XServes each with 2 quad cores running Max OS X Server 10.6.8 All networking by ethernet to a Time ...
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1answer
69 views

Prevent resurrection of dead subkernels

How do I prevent Mathematica from trying to resurrect subkernels that it has deemed to be dead? I would like to avoid this: ...
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1answer
122 views

Is Parallel Kernel Status Monitor available on Raspberry Pi?

I have used the Parallel Kernel Status Monitor documented here https://reference.wolfram.com/language/ParallelTools/tutorial/ConfiguringAndMonitoring.html on a machine running, I think, version 9 of ...
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494 views

Easy way to close all Mathematica kernels?

When developing functionalities with several parallel kernels, when a bug happens, I often have to manually close all parallel kernels (using the Task Manager in Windows) in order to start again from ...
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359 views

How to simultaneously monitoring parallel computations in different Kernels?

I have a question about monitoring parallel processes. Let's suppose that I am running the following code with 5 active Kernels. ...
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1answer
998 views

How does Mathematica detect the number of cores in a system?

I'm running Mathematica 10.3.1.0 on a machine with 16 cores, but Mathematica (in the Parallel settings) says "Number of processor cores is 8." It's a 16-core Opteron 6300 chip on an Ubuntu system. All ...
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1answer
181 views

Eigensystem on HPC

I am submitting Mathematica jobs to an HPC. I have a large matrix that is a function of (x,y) and I am diagonalizing it for around 500 points in the plane. My initial idea was to request a node with ...
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1answer
145 views

Problems with ParallelDo

As example I have the following two image sets (10 images each, png format, 8 bit gray scale) in two different directories and want to determine the mean intensity of each image: set 1: https://drive....
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2answers
336 views

ParallelTable vs. Table: Parallel gives NMinimize:nnum error

I have run into an issue where I am getting nnum errors when I use ParallelTable, which I do not get when I use Table (and even ...
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328 views

Creating a version of ParallelTable that parallelizes over all levels

Mathematica's ParallelTable (or any Parallel function based on iterators, like ParallelDo) only parallize the computation for the top level iterator (even with `Method -> "FinestGrained"' set). For ...
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1answer
556 views

How to Export from ParallelDo? [duplicate]

I'm running a simulation with parallel, and I want the results from each parameter set exported to a file whenever it's done (because the parameter space is huge and my computer doesn't have enough ...
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1answer
809 views

Setting up parallel remote kernels

I'm having trouble setting-up a parallel remote kernel. I have correctly set-up remote kernels and can use them instead of the local kernels, by executing tunnel.sh ...
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1answer
356 views

clear variables on parallel kernel

Short question: what is the proper way to clear a variable on a given kernel ? AND how can I ensure that the memory will indeed be freed subsequently ? Full question. Let me elaborate this question ...
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1answer
360 views

Dynamic Output during ParallelMap

I can't seem to figure out how to dynamically output a variable that is being used in a parallel evaluation. Below is an example function that demonstrates my problem. ...
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1answer
2k views

Parallel evaluation and memory use

I have never used Mathematica's parallel evaluation before and have some trouble getting it to work properly. For the record, I am running Mathematica 9 on Linux with an Intel Core i7 processor (4 ...
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1answer
410 views

Build recursion in parallel?

Problem Let's define a simple recursion. f[1] = 1; f[n_] := f[n] = f[n - 1]*n; If I evaluate f in parallel ...
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Optimize Use of PeakDetect in Mathematica

I am quite new to Mathematica and I am looking for some advice in order to improve and optimize my code. Here is what I am trying to do: Open a stream Read the stream line by line and store it in "...
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89 views

Random number generation within Compile and Parallelization->True

According to this thread RandomChoice is a compilable function. I use it to generate random numbers in a compiled function with parallelization enabled. I wrote ...
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Efficient Parallelization of PermutationReplace

I am generating the orbit of a partition of a set of size $n$ under the action of the symmetric group $S_n$. PermutationReplace won't allow itself to be parallelized. Why is this ? Is it because the ...
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479 views

Can't Launch Kernels, Updating from Wolfram Research Server

So, I'm running Mathematica on an HPC cluster using the math module command line interface. I'm trying to figure out some problems with attempting to parallelize my ...
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Random Number Generation on Parallel Cores [duplicate]

So, I've noticed an odd trend in some of my Mathematica results recently- I'm running large Monte Carlo simulations on a system that involves running several jobs independently, each on a different ...
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115 views

Is there a clean way to parallelize multi-index tables?

The documentation of ParallelTable indicates that if you want to parallelize the evaluation of a table of more than one dimension, such as ...
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208 views

ParallelTable slow down, Region functions

I am experiencing speed issues with ParallelTable. There are a few related problems on SX posted here and here, but no resolution. The various respondents to those ...
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158 views

Improving the speed of an optimization algorithm via compilation and parallellization

I have written an implementation of eight variants of the PSO-algorithm and I want to test them over a set of test functions. I am using parallelization as it improves the speed a lot and I have also, ...
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The change of precision doesn't work in ParallelDo. Is it a bug in Parallel?

Cross-post: http://zhidao.baidu.com/question/2075301703219376588.html Input: ...
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Mathematica + RasPi + Parallela = Kaboom?

Is it possible to use the Parallela computing platform to enhance Mathematica computing on a Raspberry Pi? It's not at all clear to me how to interface the two boards (here it says it's done via ...
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210 views

Raster with ColorFunction is blank when Dynamic Updating is disabled

UPDATE Today I was having these WaveletScalogram problems again. I think this is ultimately some kind of interaction issue with Dynamic. I have narrowed it down to ...
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3answers
1k views

How can I suppress Print in parallel evaluation?

When using a function that includes Print statements, one can suppress the output by ...
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467 views

Why does ParallelDo return wrong number of results

I am testing out some optimization algorithms. I have written the code with a Do loop inside a Do loop. The inner loop is the algorithm itself and the order the steps are executed is very important. ...
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740 views

Errors when using ParallelTable inside a package

I'm developing a package that contains a function that requires evaluation of an expensive Table, so I use ParallelTable instead....
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261 views

Parallelize function evaluation with different parameters

How do you run the same function multiple times and at the same time, but with different parameters? I have had a look at ParallelEvaluate[] but it is meant to run ...
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630 views

How to use multicore in this case?

Say I have something like this: myfun[dataA,X1,Y1,Z1,W1]; myfun[dataB,X2,Y2,Z2]; myfun[dataC,X3,Y3,Z3]; (* with many more of the same *) Each would take about 5 ...
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113 views

4X4 matrix of distinct cubed integers with identical row and column sums

I wrote the following code: ...
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1answer
159 views

Optimization: Differences between Map and ParallelMap

I just was studying Map and ParallelMap in a MacBook Air of 2 kernels. So, I tried comparing the AbosoluteTiming of these input lines and the outputs sorprised me because I thought a ParallelMap would ...
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94 views

Shadowing of symbols with ParallelEvaluate and packages

I'm new to Mathematica's parallel evaluation and can't really figure out how to properly use packages on parallel kernels: I get ::shdw messages complaining about ...
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2answers
325 views

Elegant way to partition list to be faster than `ParallelTable` (using `ParallelSubmit`), or some alternative?

Suppose you have a function fun[x_] := (Pause[.05*x]; x^2); of which you know that its evaluation time increases with its argument - in this case obviously ...
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1answer
248 views

How to further accelerate arithmetic with Fermat Pseudoprime and Fibonacci number

I've been working on this all night, and I have made this go pretty fast, compared to my first iteration of the program, but now I'm out of ideas. I'm trying to write a program to test (by good old ...
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295 views

ParallelSum vs. Sum: New functions also defined in other Kernels?

Set-Up: While I had tested a few toy examples that ParallelSum produces the result faster than the Sum, here I encounter one example in my code that the ParallelSum produces either wrong/incorrect ...
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1answer
808 views

Why can't Mathematica parallelize this?

The following code makes mathematica print "ParallelTable::nopar1: [...] cannot be parallelized; proceeding with sequential evaluation." ...
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1answer
195 views

Run multiple NDSolve Simultaneously

In a previous question I asked how to speed up the performance for NDSolve for a single evaluation. With the help provided, the solution is much faster. Now, I'd like to run the same code in different ...
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1answer
220 views

ParallelEvaluate: Evaluation Rules and Increment

I'm trying to understand how ParallelEvaluate works, considering the two following snippets: ...
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1answer
133 views

Why Does Parallelization Not Speed Up these Seemingly Well-Parallelizable, Simple Functions?

Original Example Consider function f, a parallelized version fPar, and a coarsest-grained parallelized version ...
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1answer
920 views

Parallelization does not use all cores fully

On a new laptop with a 6-core i7-8850H in Mma11.3, I'd like to use its full capabilities. Unicore code ...
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2answers
324 views

Mysterious behaviour of ParallelTable

This question is related to Export bug in combination with ParallelTable?. The following code shows an even stranger bug than in the upper question. The y-axis should always be logarithmic, but in ...

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