Questions on parallel computing in Mathematica.

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3
votes
1answer
56 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
99 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 ...
6
votes
1answer
107 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
64 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
117 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
62 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
151 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
112 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
100 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
341 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?
3
votes
0answers
78 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
308 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
143 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
95 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
108 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
56 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
29 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
78 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
92 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
64 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
98 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
106 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
192 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
82 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
140 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
102 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
108 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 ...
6
votes
3answers
279 views

Parallel and non-Parallel functions return different results?

A friend of mine observed that when running ParallelMap or ParallelTable that he would get different results than when running ...
3
votes
1answer
197 views

How can I understand this short example?

First launch kernels LaunchKernels[4] {KernelObject[5, "local"], KernelObject[6, "local"], KernelObject[7, "local"], KernelObject[8, "local"]} Then I calculate ...
2
votes
0answers
85 views

Is it possible to automatically apply Parallelize when possible

Parallelize in Mathematica is pretty easy to use. Most of the time, applying Parallelize to an expression, it tries to evaluates ...
1
vote
0answers
42 views

Inconsistent font rendering when using a remote kernel on a different OS

I have a Mathematica 10.0 on Linux and one on OSX. I'm using the OSX as a remote kernel. During parallel computation, if I render some graphics, the fonts and axes are not rendered the same way ...
8
votes
2answers
175 views

How to write a custom ParallelTable command that monitors progress automatically

I am using a lot of ParallelTable and want to avoid wrapping it in a Monitor call each time. Since each of the calls inside ParallelTable will already consume considerable time, I do not mind the ...
2
votes
0answers
67 views

Export on local machine results of a parallel computation using remote kernels [duplicate]

I've got a long calculus to do with Mathematica. I've Parallelized the code using local kernels and remote kernels. I'm using a ParallelDo loop with an ...
3
votes
1answer
109 views

Mathematica 10, With and ParallelEvaluate: New syntax?

Consider the following trivial code to evaluate something on a parallel kernel ...
1
vote
1answer
93 views

Parallel execution on CPU

i developed following code: ...
5
votes
2answers
181 views

Why doesn't ParallelTable work on this very simple example?

For some reason, I'd like to use ParallelTable with a variable number of iterators. Table[a[1], {a[1], 0, 10}] works fine: ...
0
votes
1answer
172 views

ParallelTable slower than Table in the presence of an Association?

So after testing some things I am completely reformulating my problem. First an example ...
5
votes
2answers
210 views

ParallelMemberQ

I tried to make a parallel version of MemberQ for use with a large list, but failed miserably in terms of performance. I used Partition to subdivide the list and ParallelMap to perform the MemberQ ...
2
votes
0answers
76 views

How many kernels to set based on CPU?

Looks like 4 kernels are enough? My CPU is i7 4790K as given here. Does it also depend on the tasks and the codes? My understanding is that regardless what the benchmark says, I could always use ...
5
votes
1answer
282 views

Reap, Sow with Parallelize: bad performance, why?

I have a question about the performance of Reap and Sow with Parallelize. I am aware of the following questions How to collect result continuously (interruptible calculation) when running parallel ...
9
votes
1answer
552 views

Does Mathematica take advantage of hyper-threading (if it is available)?

I do not know much about computer architecture, but some Intel processors have hyper-threading technology, which can apparently improve parallelization for applications that take advantage of it. In ...
4
votes
1answer
190 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 ...
1
vote
1answer
141 views

Making ReplaceAll faster

I have a list of functions ncalc that is calculated by ...
4
votes
2answers
137 views

Running bits of code in a separate kernel

I am using Mathematica to generate 3D graphics frame for a video. The process goes as follows: Loop over a counter i Use ...
0
votes
0answers
94 views

Can LinearSolve use Parallelize and WorkingPrecision in computation

I am looking for a two things while calculating the large array matrix equation: 1) To increase the precision in simple LinearSolve[] function 2) To find a way to parallelize the computation on all ...
3
votes
1answer
228 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 ...
19
votes
1answer
242 views

Two, maybe related, issues with ParallelTable

I will use a very simple example for demonstrating two issues I face with ParallelTable, one with respect to the speed and one with respect to the use of memory. These issues might be related. Let us ...