Tagged Questions

Questions on parallel computing in Mathematica.

learn more… | top users | synonyms

5
votes
1answer
238 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
80 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
170 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
97 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
167 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
168 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
58 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
233 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
490 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
476 views
4
votes
1answer
287 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
479 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
111 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
407 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
115 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
204 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
71 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
594 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
144 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
122 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
235 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
219 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
468 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
323 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
149 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
206 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
208 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
232 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
258 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
375 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
217 views

Parallelization of REvaluate[]?

Is there a way to run several RLink computations via REvaluate[] in parallel, e.g. with ParallelTable[]?
12
votes
3answers
728 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
257 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
416 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
687 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
252 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
144 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
100 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 ...
3
votes
1answer
69 views

local logfiles for remote kernels

I'd like remote slave kernels to produce log files on my local machine, subject to the following constraints: 1) I don't want to install a distributed filesystem or do other administrative work on ...
2
votes
1answer
85 views

How can I set the kernel for CreatePalette?

I have written some code that requests some calculations from an SQL server every N seconds and uses a palette: CreatePalette[Dynamic[DateListPlot[...]]] I ...
11
votes
3answers
303 views

Suspecting bug in Parallel Framework

I've reduced my actual problem to: ParallelEvaluate[ Module[{slot=1}, Slot[slot] ] ] gives error messages that I think shouldn't be there. It seems I can ...
2
votes
1answer
535 views

3 hour calculation? ParallelMap & ParallelTable

I'm having some problems with slow Mathematica code... I'm basically doing a computation that's is expected to take 3 hours (!) in my Core i7 with 4 processors... I'm basically computing an index (of ...
6
votes
1answer
357 views

Export graphics in parallel

I run a heavy simulation, using NDSolve and the method of lines. This means that the result of NDSolve is a list of, say, ...
7
votes
1answer
233 views

how can I avoid CPU waste (by master kernel) using WaitNext?

I'm using WaitNext in Mathematica for parallel processing on Mac OS X. I have 4 processors on my MacBook and LaunchKernels[] ...