Questions on parallel computing in Mathematica.

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4
votes
2answers
206 views

Using Multiple Kernels When Making Plots

I am running a notebook that makes multiple plots. I define a function and then I want to plot that function for different choices of parameters, using RegionPlot. ...
0
votes
0answers
43 views

How to construct a list in a For Loop nested in a Parallel Loop [duplicate]

I've the following problem I cannot solve. I allocate an empty matrix, v, of size n x m. Then I want to do a Parallel loop (ex. ParallelDo), and do some operations (described by a function ...
4
votes
0answers
195 views

Discriminant of Characteristic Polynomial

I'm doing a calculation which finds the characteristic polynomial of a matrix with rather complex entries and then determines the discriminant of that polynomial. For smaller matrices up to around 7x7 ...
6
votes
1answer
120 views

Finer granularity with ParallelDo

ParallelDo only parallelizes by the innermost variable. Is it possible to distribute the calculation over all the points (all the variable) separately? let me ...
2
votes
2answers
176 views

Definitions inside ParallelTable?

How can I make definitions inside ParallelTable to use them outside? For example, if I execute: ...
1
vote
1answer
226 views

ParallelTable and DistributeDefinitions

I have a function in the following form: function[...] := With[ {...}, Table[ anotherfunction[i, j, ...], {i, ...}, {j, ...}, ... ] ] If ...
5
votes
0answers
1k views

Threads vs Cores: How many kernels need to launch in parallel Mathematica?

I have a dual-core intel machine. I would like to test how many parallel local kernels should be launch to get the optimized performance. Knowing that the HyperThreading technology of Intel could run ...
14
votes
1answer
348 views

How to constrain memory usage on HPC?

I found the performance of built-in function MemoryConstrained is very poor. It stops the evaluation after the memory limit has already been exceeded greatly than ...
15
votes
1answer
327 views

How to parallel the computation tasks according to machines instead of kernels

On a HPC, there are many computation nodes, each node corresponds to an independent machine. Every node has several cores, for example 8 per node. Mathematica can launch remote kernels on different ...
2
votes
1answer
384 views

Suppress warnings in ParallelTable

I'm using ParallelTable to evaluate a function that involves NIntegrate. There are a lot of ...
2
votes
2answers
183 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 ...
6
votes
1answer
300 views

Is matrix multiplication automatically done in parallel in Mathematica 9?

In good old Mathematica versions (5.2, 6.0), matrix multiplication was automatically done in parallel. For example, on an 8-core machine, define two square real matrices: ...
1
vote
0answers
54 views

Parallelizing an associative binary operation

I have an associative binary operation '.', which I often use in this sort of way: result = expr1 . expr2 . expr3 . expr4 The ...
10
votes
2answers
411 views

Why is ParallelMap way slower than Map

I recently tried to use ParallelMap instead of Map and to my surprise encountered that ...
5
votes
2answers
230 views

ParallelMap and Sow/Reap - not behaving as expected? [duplicate]

Is ParallelMap and Parallelize@Map expected to work with Sow and Reap construct. This is a rather brief toy code to find all Primes just to force the use of Sow/Reap inside Map ...
-4
votes
1answer
180 views

How to use all the kernels efficiently

We build a project with Java and Mathematica technologies. For this project we have written a bunch of functions in Mathematica and integrated some functions in one ...
0
votes
1answer
109 views

Problem with List Dimension Outer Map [duplicate]

I am currently handling a big list which has the following dimension: {6, 3, 4, 2, 2, 1, 8} where the last number 8 represent a ...
5
votes
1answer
223 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 ...
5
votes
2answers
210 views

Parallelizing or optimizing a script for calculating the size of all pairwise intersections between collections of sets

I need to speed up or parallelize an operation that looks essentially like this: ...
9
votes
1answer
481 views

ParallelEvaluate for function minimization

Is there a parallelized version of a minimization routine available in Mathematica? The objective function is non-linear and the gradients have to be numerically computed. Every function evaluation ...
1
vote
1answer
134 views

ParallelTable of ParametricNDSolve objects fail

There seems to be a problem with ParametricNDSolveValue togeteher with ParallelTable First we create a ParametricNDSolveValue object ...
0
votes
1answer
119 views

Parallelize matrix operations

I'm trying to reduce to a minimum the time of some matrix operations. When I don't parallelize and write the code in the most compact form I get the operation done in around 1sec (is this good? the ...
2
votes
2answers
306 views

Is there a way to parallelize the convolution component of EdgeDetect?

Provided an image like - test = Import["http://upload.wikimedia.org/wikipedia/commons/d/d5/Sunflowers.jpg"] We can run ...
5
votes
0answers
121 views

What do the elements of the Parallel Kernel Status screen mean?

I just managed to get my multiple kernels up and humming on a new multi-core machine, which I am quite happy about. I am slightly at a loss, though, about the meaning of the different parts of the ...
10
votes
1answer
202 views

How to monitor the communication between parallel kernels

Recently I increased the problem size in my code, and it scales up very badly using ParallelTable. With a lot of help from the this community, it seems that the ...
5
votes
1answer
270 views

How to avoid unpacking from Language`ExtendedFullDefinition

Consider this code: LaunchKernels[]; On["Packing"] a = RandomReal[{0., 1.}, {64, 30000}]; ParallelMap[Fourier, a]; // AbsoluteTiming Developer...
9
votes
1answer
290 views

Why I only get 2X speedup when parallelized with 16 kernels

I'm trying to parallelize a function by ParallelTable, and it seems the speedup is not very good. I have 16 parallel kernels on my computer node: ...
3
votes
1answer
184 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 : ...
2
votes
0answers
117 views

Whether NIntegrate evaluation is multithreaded or not?

About MultiThread evaluation I am talking about here, see this post I am NIntegrate the function grarm[e, 3, dimension, 1, 1, 0.005]. There is matrix operation in ...
2
votes
1answer
256 views

How to parallel this nested table efficiently?

I have an 8 core CPU and want to parallel evaluate the following nested Table Table[Table[expr[i,j], {i,1,10}], {j,1,4}] But ...
2
votes
1answer
247 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 ...
2
votes
0answers
81 views

Setting Up Lightweight Grid On Multiple Clients Programmatically

I have a number of computers which all might need to use the same (client) configuration for the Wolfram Lightweight Grid at some point. I know that there are ways to programmatically set certain ...
8
votes
1answer
382 views

How to do computations simultaneously in multiple notebooks? [duplicate]

I have a Mathematica script which takes a few hours to run. I want to be able to open another notebook while it's running and do some other computations. I have enough many cores on my computer for ...
5
votes
1answer
858 views

Parallelize plotting

I'm using Mathematica to make a few 3d plots. For the sake of generality, let's say they are unrelated to each other (so I can't imagine making a table out of them). However, the machine I'm using has ...
3
votes
2answers
602 views
5
votes
1answer
468 views

Why is parallel slower?

I always assumed that distributing a computation is faster, but it isn't necessarily true. When I do Sum[i,{i,10^4}] I retrieve an answer much faster then if I do ...
0
votes
1answer
656 views

ParallelTable 70 times slower on 16 cores than Table on single core

Consider these code(sorry it's messy), why the ParallelTable version is 70 times slower than the Table version? ...
0
votes
0answers
130 views

Strange ParallelMap behavior

Let the symbol V denote an element of some vector space and nV its norm. Let lin be a linear ...
1
vote
2answers
571 views

Integration and Parallel Computing in Mathematica

In mathematica, how would I use parallel computing (or paralleltable) to compute the integrals of $x^2$, $x$, $3x$ from $x=0$ to $10$ just like in the first answer of ...
2
votes
1answer
125 views

ParallelTable slowdown for a task involving ComponentMeasurements

I'm having trouble understanding a slowdown associated with code I'm running, which should be trivial to parallelize. My code looks something like this: ...
3
votes
0answers
299 views

To what extent can NonlinearModelFit be sped up?

Can NonlinearModelFit be parallelized or compiled to allow one to achieve a scalable speedup for a fitting procedure? Attempting to use this function to fit a ...
2
votes
0answers
93 views

How can you link Parallel Mapping and Error tracking

Following this question and the comments made, together with the information in this question, the following code allows error tracking and debugging very nicely. ...
8
votes
2answers
898 views

Writing data to a common file during parallel processing

I am executing a loop, and in each loop I have to store a parameter in a file. It is like ...
1
vote
0answers
150 views

Why doesn't ParallelMap improve the performance of FoldList?

This question arose during my analysis of the following problem: filling gaps. (The code used here is Simon Woods's work.) FoldList seems to not cooperate with ...
4
votes
2answers
139 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}] ...
2
votes
0answers
133 views

correct usage of ParallelTable

I am trying to parallelize my script. Here is a MWE of how I have done it: ...
6
votes
2answers
314 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 ...
8
votes
2answers
241 views

Distribute and analyze large datasets

I need to analyze very large datasets, and they obviously don't fit in a computer memory. I need to produce some statistics on these datasets, and this brings me here: How can I make some statistical ...
12
votes
1answer
573 views

How to run an external program in parallel with a Mathematica package?

Under Mathematica 8 (Linux x84_64) I was able to run an external program in parallel from a Mathematica package. However this procedure breaks down under Mathematica 9. Within my Mathematica package ...