Questions on parallel computing in Mathematica.

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7
votes
1answer
118 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 ...
1
vote
1answer
53 views
5
votes
2answers
49 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 ...
3
votes
0answers
73 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 ...
2
votes
2answers
231 views

Follow each pixel brightness in set of images (Memory constrained)

I have a set of 2700 consecutive png images (8bit, 2048*2048 pixels). I would like to visualize the intensity variation of each pixel vs. image number. Here is an example of 10 images: ...
5
votes
1answer
138 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 ...
35
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 ...
3
votes
1answer
42 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: ...
10
votes
1answer
295 views

Partial Differential Equation in Parallel

is there any native way to implement multi-core parallel solving of PDE in Wolfram Mathematica? WM 10 now supports Finite Elements Method, but it is actually useless without parallelization. Usually ...
1
vote
1answer
80 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 ...
0
votes
1answer
45 views

Strange behavior of ParallelTable

I was trying to carry out the following calculations: ...
1
vote
1answer
29 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
38 views
1
vote
2answers
285 views

How to optimize this code?

I am implementing a code that works correctly but it takes too much time. I did not see how to optimize it to be run quickly. Here is my code: ...
3
votes
1answer
138 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 ...
12
votes
2answers
536 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 ...
32
votes
3answers
811 views

Parallelize evaluation of function with memoization

I have a complicated function that I need multiple times, so I want to memoize it and have the first evaluation done in parallel. Unlike in my example below it's not a continuous function, so ...
18
votes
1answer
218 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 ...
4
votes
0answers
53 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
60 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
34 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, ...
3
votes
2answers
145 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
50 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 ...
6
votes
2answers
2k views

why I can't define a commutator operator in this way?

I am trying to define some operators I used frequently. For example, I defined a KroneckerProduct operator as $\otimes $ as follows: ...
0
votes
0answers
33 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
117 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
165 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 ...
5
votes
1answer
84 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 ...
-1
votes
1answer
67 views

Parallelize in Mathematica [duplicate]

Here is two test to understand the parallelize in Mathematica: ...
1
vote
0answers
79 views

Can equation solving be done in parallel?

I'm solving a set of equations that look like: ...
3
votes
1answer
87 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 ...
3
votes
1answer
47 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 ...
0
votes
0answers
72 views

What is the right way to combine a Package, Module, ParallelTable and NIntegrate?

I am stuck with a curious problem. I would like to to have a package from which i can call a function test[path], which then performs a time consuming numerical ...
10
votes
1answer
301 views

Using Compile to speed up Function with PermutationProduct [closed]

I have the following fairly simple routine dot involving PermutationProduct that I wish to speed up using ...
6
votes
1answer
95 views

ParallelTable and Random

Each time I execute the following code it generates the same cylinders with the same format. ...
0
votes
0answers
48 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 ...
8
votes
4answers
561 views

Efficient way to utilise Parallel features to make use of many cores

Let's say I have 100 cores/kernels as my disposal and want to compute a function of two variables f[x,y] over {x,1,10}, ...
9
votes
2answers
386 views

MapThread and parallel computing

This time I have a very short question. Is there a deeper reason why ParallelMapThread does not exist? Regards, Frink
0
votes
0answers
56 views

Is it possible to somehow parallelize PadeApproximant in Mathematica?

Is it possible to somehow parallelize PadeApproximant in Mathematica? I'm dealing with a too long function (including exponential and trigonometric terms) in ...
-1
votes
2answers
81 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 ...
3
votes
1answer
103 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? ...
3
votes
1answer
58 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
578 views

Parallel computation of a system of differential equation

I need to solve a system of differential equations which contains, at minimum, ten thousands of differential equations. Actually, I am trying to solve density matrix equation $$\frac{d}{d t}\rho(t) = ...
5
votes
2answers
59 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 ...
0
votes
1answer
102 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 ...
4
votes
2answers
88 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 ...
1
vote
1answer
196 views

Appending elements to a list in parallel table

Is there any way to store values in a list that is being computed in parallel? For example, if ParallelTable is computing some ...
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?
5
votes
2answers
207 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 ...
3
votes
0answers
67 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, ...