Questions on parallel computing in Mathematica.

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9
votes
1answer
383 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
108 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
99 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
249 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
90 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 ...
9
votes
1answer
171 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
240 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...
1
vote
0answers
83 views

Why does ParallelTable give different answer than Table [closed]

Consider the following code a0 = 6.; ls1 = ParallelTable[k, {k, -π/a0, π/a0, π/a0/100}]; ls2 = Table[k, {k, -π/a0, π/a0, π/a0/100}]; ls1 == ls2 (*False*) Why ...
9
votes
1answer
278 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
174 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
100 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
177 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
175 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
60 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 ...
7
votes
1answer
241 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
532 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
492 views
4
votes
1answer
295 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
491 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
113 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
421 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
116 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: ...
1
vote
0answers
216 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
74 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. ...
7
votes
2answers
627 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
145 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
126 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
125 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
245 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
222 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 ...
10
votes
1answer
475 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 ...
9
votes
3answers
332 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 ...
3
votes
0answers
152 views

Mathlink and multithreading

In order to make my computations faster I have developed a C/C++ application calling Mathematica kernel and performing many operations using Mathematica functions for equation solving. Now I want to ...
5
votes
0answers
209 views

Parallelizing is much slower than single kernel evaluation?

Starting with a vector of matrices, tVec, I would like to parallelize the multiplication of each element with the same matrix ...
4
votes
0answers
147 views

Raster with ColorFunction is blank when Dynamic Updating is disabled

UPDATE Today I was having these WaveletScalogram problems again. I think this is ultimately some kind of interaction issue with Dynamic. I have narrowed it down to ...
2
votes
1answer
213 views

Mathematica 7: Problems when evaluating Fourier inside a ParallelTable

after I got such a great response for my first question on this site, I'm very encouraged to asked my second one! So here it is, very generally: To speed up a "row-wise" (i.e. 1D) operation on a ...
2
votes
1answer
236 views

How can I prevent these warnings while using ParallelTable

I have this code to find all the permutations of a set of letters that form legal words. ...
6
votes
1answer
273 views

Launching remote slave kernels on HPC causes slow down

I had a post earlier regarding how I can run Mathematica at a HPC cluster (running PBSpro) by having a single MathKernel launch ...
7
votes
3answers
397 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}, ...
2
votes
1answer
219 views

Parallelization of REvaluate[]?

Is there a way to run several RLink computations via REvaluate[] in parallel, e.g. with ParallelTable[]?
12
votes
3answers
774 views

Mathematica Parellelization on HPC

I'm currently using Mathematica on a High Performance Cluster (HPC) which consists of many compute nodes each with around 16 cores. I currently run my Mathematica script on 20 of the nodes that ...
2
votes
1answer
137 views

Mathematica 9.0 problem: ParallelTable with SQLExecute

I have run into the following problem: when I try to run the following code in Mathematica 9 I get SQL connection error on all kernels. The code is: ...
0
votes
1answer
260 views

Why does my attempt at parallelization not work?

I want to run some function with different parameters, parallel on 4 cores (i5). When I run it without using Parallelize, processor has ~25% utilization. It's a ...
10
votes
1answer
426 views

Parallelization and Hadoop

The short question: Has anyone used Mathematica in conjunction with Hadoop and does Mathematica's built in parallelization play well with Hadoop? The long version: So I have a Mathematica program ...
3
votes
2answers
726 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: a_$ \otimes $b_:=a.b-b.a and this works fine. Then I want to ...
3
votes
1answer
260 views

Determining the partitioning of Do loop iterations between kernels?

Say I have some Do loop that I'd like to evaluate in parallel: Do[Something, {i, 1, M}]. I'd like to split this list up into ...
1
vote
1answer
147 views

Understanding a slowdown associated with wrapping a set of nested Do loops with a ParallelDo expression

I have a set of set of nested Do loops that require data from three different arrays (though the position from each array is fixed per cycle of the outer Do loop). Let's call these arrays: ListA, ...
2
votes
1answer
104 views

Parallel computing NInverseFourierTransForm

I am running the code below, and it works perfectly. I have some function in Fourier space, and I take the numerical InverseFourierTransform. However, I will have ...
6
votes
1answer
93 views

Is it safe to use older version subkernels with a newer version main kernel?

At the moment we only have access to version 8 of the Lightweight Grid (i.e. version 8 of the Mathematica kernel). Is it safe to run version 8 subkernels together with a version 9 main kernel? It ...