Questions on parallel computing in Mathematica.

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18
votes
1answer
453 views

Mma 10: Half the parallel power (Macs)?

Here is a comparison of the parallel kernels launched under Mathematica under v9 and v10, on the same identical current 2014 R2-D2 Mac Pro ... [ Update: Valerio has commented that the same issue ...
0
votes
1answer
62 views

ParallelMap returns incorrect results over Map

I've written a function to pull in the useful column of a large data file: ...
6
votes
0answers
97 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 ...
2
votes
0answers
94 views

ParallelSum in Mathematica 9 vs 10

Here's part of a package I'm working on: ...
0
votes
0answers
65 views

strange timing behavior

The following code is from a book about Mathematica. ...
0
votes
0answers
35 views

Shared variable impacting speed? [duplicate]

I am using a shared variable as a progress indicator ( via SetSharedVariable[counter] and then Dynamic[counter]), to keep track ...
2
votes
0answers
40 views

Timing of ParallelDo versus Do: simple example [duplicate]

I'm trying to understand why a simple do-loop takes substantially longer when done in parallel than sequentially: ...
0
votes
0answers
57 views

Death of parallel sub-kernels

EDIT : Finally, the new Mathematica 10.0 seems to fix it. I have a little parallelization problem. I wrote a code to generate a quasicrystal by dynamical generation. Here the code: ...
0
votes
0answers
44 views

Need to parallelize function f in a iteration

I don't have experience using Mathematica for parallel calculation. I need to do something simple to parallelize the calculation of f which is calculate each time n iterates: ...
25
votes
1answer
527 views

Is it safe to launch/close kernels in the middle of a parallel calculation?

It appears that it is possible to launch additional kernels (or close existing ones) during a parallel calculation. The newly launched kernels will be utilized for the rest of the calculation. ...
6
votes
2answers
221 views

Does Eigenvalues evaluate in a parallelized way?

I use mathematica on a computer with linux operating system. The computer has 2 cpus and each cpu has 4 cores, so there are totally 8 cores available. Now I got confused with whether the evaluation ...
2
votes
1answer
77 views

ParallelEvaluate: Evaluation Rules and Increment

I'm trying to understand how ParallelEvaluate works, considering the two following snippets: ...
19
votes
1answer
1k views

Why won't Parallelize speed up my code?

What reasons are there that can cause parallelized Mathematica code not to run with full performance?
4
votes
0answers
94 views

How to force the compilation language to be C++ (not C) in CreateExecutable or CreateLibrary

I'm trying to speed up a section of a Mathematica 9.0.1 notebook by performing some calculations in C++ with the Cilk Plus and Threading Building Blocks tools available for the Intel C++ 14.0 compiler ...
3
votes
1answer
159 views

Optimization of power tower fractal generator [closed]

I tried to optimize the code for generating power tower fractals from here. As the author suggested, I tried to memorize the points already tested in a list. Here is my code : ...
0
votes
0answers
15 views

How can I set global computation options ($MaxPiecewiseCases) for parallel kernels? [duplicate]

I'm trying to do a calculation in parallel that requires setting $MaxPiecewiseCases. How can I do this? This small test case doesn't work for me: ...
8
votes
1answer
116 views

Experimental`NumericalFunction in NMinimize solution

I try to make a number of optimizations using this code: ...
2
votes
1answer
195 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 ...
0
votes
0answers
28 views

Notebook stops using extra kernels after some time

Have a mathematica .nb job where I've programmed to run on parallel. Everything goes fine for about an hour but after this most kernels just stop being used by the program. I can see this happing in ...
1
vote
1answer
25 views

$IterationLimit and parallel computing

Short question: How can you set $IterationLimit for parallel computation? I thought just setting $IterationLimit = Infinity ...
0
votes
0answers
46 views

Cluster integration: Problem connecting to Sun Grid Engine

I'm trying to launch some kernels in a cluster engine running Sun Grid Engine using Cluster integration. But I'm getting the error "Cannot find components required for SGE". ...
2
votes
2answers
108 views

Executing several input cell simultaneously with parallelization

How can I execute more than one input cell simultaneously using different processor. For example consider this two cells ...
1
vote
0answers
68 views

Diagonalization in parallel

I would like to diagonalize one unitary non-sparse matrix of size 12870 with complex number entries (not symbols, this is really a numerical problem). Is is possible to make eigensystem run in ...
0
votes
1answer
75 views
0
votes
1answer
43 views

A problem with parallelize

I am experimenting with Parallelize and ParallelTable This is the code I am using: ...
1
vote
1answer
50 views

Using parallel computing to build a matrix recursively

I am trying to compute the product of a sequence of matrices using the command ParallelDo. Of course, if I use the simpler command ...
0
votes
0answers
41 views

How to parallelize a the calculation of a vector function which is inside a recursive formula

I need some help with parallelizing the calculation of a vector function F which is inside a recursive formula. An example of the code is below for few iterations. ...
2
votes
0answers
65 views

ParallelTable and expensive functions

I would like to build up a 2D-Table using ParallelTable as follows ...
0
votes
1answer
170 views

Parallel computation of NDSolve and a problem

I used this code to solve a system of differential equations: ...
0
votes
1answer
53 views

ParallelTable and plotting result of own define funtion

I define function which return a list of numbers ...
3
votes
1answer
50 views
0
votes
1answer
130 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. It's like something ...
6
votes
1answer
96 views

Garbage collection for memoized functions on subkernels

I have a top-level function which operates on some data: findBestIntegers[data_]:=ParallelMap[optimize,data] which makes parallelized calls to an optimization ...
2
votes
1answer
115 views

Copy a variable to a specific kernel in Mathematica [closed]

I would like to copy some parameter from the main Kernel of Mathematica to the parallel kernels available. So I'm running now a command like: ...
0
votes
1answer
79 views

Can ParallelDo speed up a counting problem?

How to make parallelize the following code keeping the same "idea". The example I have in mind is more complicated, but I would like to know if a program of this structure can be parallelized? ...
1
vote
0answers
72 views

ParallelTable, ParallelDo and ParallelMap all fail on simple evaluations, a BUG? [closed]

Sorry I am relatively new to the parallel functionality mathematica.. Here is to code: ...
0
votes
0answers
61 views

How to parallelize this code

Here I obtained one code which should tests some zeros of the poly for various g, but sometimes I have to many cycles because of step and I need to parallelize the running on all cores. Classical ...
0
votes
0answers
28 views

KernelObject::rdead on local kernels

I'm trying to parallelize some tasks which involve fetching data from a URL and processing it. This is the code: ...
3
votes
1answer
56 views

Creating a parallelizable DiscretePlot

To my knowledge, DiscretePlot cannot be parallelized, although one can simulate the default behavior of DiscretePlot and get the ...
1
vote
2answers
116 views

Do multiple instances of Mathematica run completely independently?

Let me simplify the problem I am trying to solve so that the issue I face is highlighted. Say, I want to generate $n$ samples of a Gaussian random variable. I have a script (say ...
14
votes
1answer
302 views

Making Monte Carlo simulation with ParallelTable

I would like to to MonteCarlo simulations of various regressions - basically, doing OLS under various conditions to test approaches. On my macpro 2x 2.8 GHz quad core Xeon, 32 Gb RAM DDR2 @ 667 Mhz, ...
0
votes
0answers
508 views

Fastest way to create a NxNxNxN dimensional matrix

I have a function that outputs a complex number Func[x_,y_]:= blah blah; I have constructed a table of all possible values of this function. ...
2
votes
0answers
57 views

LibraryLink parallel performance

I'm trying to use a LibraryLink function in parallel. It is an embarrassingly parallel problem, so that no dependency between those parallel tasks. However I can only get the parallel efficiency about ...
11
votes
5answers
1k views

What is the fastest way to extract a substring from a huge string?

I develop an algorithm to find the most common substrings of a given length n up to a certain distance l in front of a pattern p in a huge sequence S. E.g. I want to find the most common hexamers ...
0
votes
2answers
66 views

Distributing value of variable to specific kernel

I want to distribute the value of a variable to a specific kernel in a parallel computing setup. Using DistributeDefinitions of course does the job, but it ...
1
vote
3answers
115 views

Where Statement

Is there a "parallel" way to perform these operations? Indices = {} For[i = 1, i <= Length[w], i++, If[w[[i]] < 0, AppendTo[Indices, i]]] Which gives a ...
0
votes
1answer
56 views

Launching external program in background process with ParallelSubmit

I work on the implementation of an image processing pipeline in Mathematica in which I also would like to use external programs to do certain processing steps. As an example I have macros for the ...
2
votes
1answer
81 views

SSH known hosts in Windows (Error code = 124)

I had to re-install Raspbian OS and now it has new SSH key. SSH clients usually let ignore this fact and save the new key, but not now. Mathematica gives no way to go if the Host Key was changed. I ...
6
votes
1answer
183 views

Parallel optimization of Markov Chain Monte Carlo

I'm trying to reduce the computation time of a MCMC simulation. Essentially I have a set of particles performing a random walk in a periodic random potential. The particles are independent and every ...
9
votes
3answers
312 views

Why is this parallel evaluation with Dispatch[] so slow?

Can you efficiently parallelize this? The parallel versions are much slower than the sequential version, and I'm not sure why. Does SetSharedVariable allow ...