Questions on parallel computing in Mathematica.

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3
votes
1answer
60 views

Shared variable can not be distributed again after UnsetShared

I see a weired behavior in my MM 10.3 version. Can someone reproduce it or explain what is going on? The code is easy: ...
5
votes
2answers
54 views

Why ParallelEvaluate[x = 0; {$KernelID, Dynamic[x]}] returns {{1,x},{2,x}}?

I'd expect that ParallelEvaluate[x = 0; {$KernelID, Dynamic[x]}] returns {{1, 0}, {2, 0}}, and that if in a parallel ...
5
votes
1answer
203 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 ...
39
votes
9answers
2k views

What would you ask Mathematica to do on a big system?

Our hardware supplier has given us the opportunity to test Mathematica on a big Windows system. The specs will be 1 to 4 TB of working memory and 12 sockets with 18 cores each. I got 1 full week of ...
0
votes
1answer
57 views

Strange behavior of ParallelTable

I was trying to carry out the following calculations: ...
1
vote
1answer
40 views

Array elements of a vector are not filled in ParallelTable environment [duplicate]

If I use the following code the Array arr still contains zeros. ...
3
votes
0answers
61 views

Why is a LibraryLink function, which returns a list, not parallelizing with ParallelTable?

First example: librarylink function return a list of two element ...
4
votes
2answers
228 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 ...
8
votes
1answer
202 views

Export bug in combination with ParallelTable?

I am programming with Mathematica 10.3.1.0 on Windows 10 Professional 64 Bit and have an i7-4940-MX 3,1 GHz processor (4 cores). When I use in the example code below ...
3
votes
1answer
145 views

How to speed up filling a matrix as much as possible in a loop?

In order to find the solution of an $n\times n$ system of nonlinear equations by the method $x_{k+1}=x_k-D_k^{-1}f(x_k)$ where $D_k$ is an approximation of the Jacobian and defined by \begin{equation}...
4
votes
0answers
84 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 ...
0
votes
0answers
68 views

Concerns about scheduled tasks

I'd like to know how CreateScheduledTask and StartScheduledTask work internally. When I run the following code: ...
2
votes
0answers
69 views

`ParallelTable` pending the MathKernel after execution

I have done a ParallelTable computation in script mode. After execution, the output is fine and I've got all the data I needed. but the kernel seems pending, ...
12
votes
2answers
569 views

Is it possible to Parallelize Select?

Given a large list of elements, is it possible to improve Select by parallelizing? An example: from a 10,000,000-element list of integers between 1 and 10, select ...
0
votes
1answer
56 views

Invoking functions in other kernels

Suppose one wants to parallelize as much as possible N tasks, each task produces a graphics via ParametricPlot or something like that. If the system is allowed to ...
0
votes
0answers
37 views

Parallelize Factor or Simplfy

I want to calculate the following example: Factor[ a+b+c+d+......(very complicate)] Factor[ a+e+f+d+......] Factor[ h+b+c+g+......] Usually, these calculations ...
1
vote
2answers
127 views

How to parallelize this code?

Initialize a matrix a with value of $\alpha$ in central cell as "ice", and $\beta$ in every other cell. ...
3
votes
3answers
177 views

Optimizing a series of basic matrix operations—scaling doesn't seem right with matrix size

I have a simple operation that I'd like to apply to an n×n matrix. My problem (well, one of them...) is that it runs in, say, 4 seconds for a 100×100 matrix, but it took five and a half minutes to run ...
-1
votes
1answer
80 views

Parallelize in Mathematica [duplicate]

Here is two test to understand the parallelize in Mathematica: ...
2
votes
0answers
133 views

Can equation solving be done in parallel?

I'm solving a set of equations that look like: ...
3
votes
1answer
59 views

LaunchKernels behavior

I have one processor with 2 cores on my local computer. CloseKernels[];LaunchKernels[] (* {"KernelObject"[1, "local"], "KernelObject"[2, "local"]} *) I can't ...
3
votes
1answer
102 views

Fast evaluation of a function in many points

I need to feed to an external program a number of points (in Complex128 format) generated from the numerical evaluation of some function, e.g. $e^{i \vec{k}\cdot\...
6
votes
1answer
113 views

ParallelTable and Random

Each time I execute the following code it generates the same cylinders with the same format. ...
0
votes
0answers
49 views

Time needed to solve NIntegrate is much longer than what I was expecting

I'm trying to do the following list: tablevdip = ParallelTable[{x, y, Vdip[x, y, 6]}, {x, -1, 1, .5}, {y, -1, 1, .5}];] with ...
3
votes
1answer
66 views

What does it mean when number of LaunchKernels much greater than cpu cores?

My Laptop only has two cores, In[69]:= $ProcessorCount Out[69]= 2 And ...
3
votes
1answer
126 views

Why is $ProcessorCount not equal to LaunchKernels[ ]?

Normally, number of $ProcessorCount should be the same as LaunchKernels[], but if they are not the same, what is the problem? ...
-1
votes
2answers
85 views

Using counters within parallelize

I am running a lengthy do loop and I wish to use Parallelize so that multiple kernels are used. What I do in the loop is update a set of counters that report the ...
5
votes
2answers
66 views

Parallel execution of an instructions block

I regularly use Parallelize and ParallelMap, andI've been reading the manual pages for parallel computing instructions but i could not find what I am looking for. Assume I have a sequence of ...
3
votes
2answers
160 views

Efficient and fastest way to execute 4 nested loops

I have a question regarding the use of ParallelDo. I tried to parallelize the following code involving four nested Do loops by ...
0
votes
1answer
118 views

how to parallelize nested do loops [closed]

I have four Do loops which the outer loops iterate over the inner loops. This is my code ...
5
votes
2answers
108 views

Parallel function evaluation for minimal value

I am asking myself, if the evaluation of a function f looking for a minimal value over a discrete set of values can be parallelize (brute scan for a potential ...
7
votes
1answer
550 views

Causes “libGL error: failed to load driver: swrast” an Huge Overhead in Parallel under Version 10.3?

Under Linux (SUSE Linux Enterprise 11) for Mathematica Version 10.2/10.3 I observe the following error in parallel ...
0
votes
0answers
29 views

Is there any way to use parallel computation for all code as automatically? [duplicate]

I need help to learn that Is there any way to use parallel computation for all code as automatically?
4
votes
0answers
86 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, ...
4
votes
2answers
326 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. ...
3
votes
0answers
161 views

Parallel Kernels and Hyperthreading

I am using Eigenvalues a large number of times on a machine with 8 cores. When I run Eigenvalues one time without any parallel ...
3
votes
0answers
96 views

How to speed up summing a large number of vectors

First let me explain what I am trying to do in my code. Assume that I send a very short chirp (2,000 ms long) into a domain filled with 20,000 particles randomly scattered in the domain. The ...
1
vote
0answers
111 views

Parallelization [closed]

I am new to mathematica and have the following question regarding parallelization of the code. I have an input data which is of the form ...
1
vote
1answer
61 views

ParallelDo errors using Physical Constant and a list

I am new to using Mathematica in parallel and need help with the following code. When it is not run in parallel as follow, it works. ...
1
vote
0answers
34 views

Distribute Definitions to different Evaluator

I would like to pass on a definition from one Kernel to the other. With that I mean manually configured Kernels. In this case, I do not want to use the inbuilt Parallelization options, in order to ...
2
votes
0answers
84 views

Is there a way to specify which kernel is used to import files (SOLVED)?

Following up on a previous question in which I encountered a memory leak in the JSON importer I have created a SandBox script that will run the Import and analysis on a separate kernel, which be ...
5
votes
1answer
112 views

Selecting the parallel kernels where tasks can be executed

When I use ParallelSubmit, is it possible to select on which kernel a task can possibly be executed? For example if have 3 parallel kernels, can I only use 2 of ...
4
votes
1answer
65 views

InstallJava on a parallel kernel while debugging in Wolfram Workbench

Here's my problem. I need to create a link between a client that is a parallel Wolfram kernel and a server through a Java API. I'm using Wolfram Workbench in debugging mode (like most of the time ...
1
vote
0answers
103 views

The module load only works for the first node, not all. Is there's a way to specify the full path to the math command when launching remote kernels

Running a Mathematica .m file in cluster for parallel computing. But get an error "bash: math: command not found". Is there's a way to specify the full path to the ...
2
votes
0answers
121 views

Parallel evaluation of symbolic matrix eigenvalues

I'm trying to find eigenvalues of symbolic hermitian 40x40 block matrix. It is made from 20 2x2 matrices like this: ArrayFlatten[Table[M[m,n],{m,1,20},{n,1,20}]] ...
1
vote
3answers
203 views

How to parallelize a Do loop containing URLFetchAsynchronous?

I'm have a simple piece of code: results={}; Do[If[!FailedQ[g = grab[i]], AppendTo[results, g]], {i, 2000000, 3000000}] I had thought that the simplest way to ...
2
votes
1answer
85 views

Parallel kernels cannot launch: LinkOpen::linke error [closed]

I have been regularly using parallel kernels on my machine but this morning all I receive is a cryptic error whenever I call any parallel function (LinkOpen::linke). As far as I can see sequential ...
5
votes
1answer
149 views

memory leaks using NIntegrate on parallel kernel

Bug fixed in version 10.2.0 I'm running a large computation in parallel and the memory usage of the parallel kernels is increasing with every iteration of the calculation. Neither ...
3
votes
2answers
106 views

Add Results of ParallelMap in Parallel

I'm new to coding in parallel, but I really could use it. I need a command to call a function on each element in a huge list, and then add them all up. Currently I use something like this: ...
3
votes
0answers
137 views

AppendTo or Part in a ParallelDo?

I have a question regarding how memory is managed in parallel. Specifically, I'd like to know what is the better practice when constructing an array within a ...