Questions on parallel computing in Mathematica.

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6
votes
1answer
734 views

Efficiency of ParallelDo when a global variable./matrix is being updated

(Disclaimer: I realize that the addition of matrices a and b below can be done very fast just by typing a+b. The code below is just meant to illustrate behavior similar to what I observe in much more ...
6
votes
1answer
376 views

PrintTemporary in ParallelTable

I thought of a possible answer to Monitor doesn't work with ParallelTable but it doesn't work as I hoped it would. This accumulates print cells instead of deleting them as intended. Can it be ...
5
votes
1answer
163 views

Parallel evaluation of Image and Rasterize problem

The following command: ParallelTable[Image[Graphics[{{Red, Disk[{5, 5}, 4]}}]], {i, 10}] shows a very strange behaviour. It starts a new Mathematica process on ...
5
votes
0answers
160 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 ...
5
votes
1answer
269 views

Build recursion in parallel?

Problem Let's define a simple recursion. f[1] = 1; f[n_] := f[n] = f[n - 1]*n; If I evaluate f in parallel ...
3
votes
1answer
66 views

Why doesn't my expression evaluate at the subkernel?

Consider this code: ...
3
votes
1answer
218 views

Issue in ParallelTable after evaluating another function using NDSolve and FindRoot. What is wrong with this inverse?

I am trying to find the inverse of a function which is defined through NDSolve and NIntegrate. The question is pretty similar ...
3
votes
2answers
582 views
3
votes
1answer
316 views

Why can't Mathematica parallelize this?

The following code makes mathematica print "ParallelTable::nopar1: [...] cannot be parallelized; proceeding with sequential evaluation." ...
2
votes
2answers
67 views

How to share numbered variables between kernels

Supose I have two variables v[1] and v[2]. I used: SetSharedVariable[{v[1], v[2]}] Then, ...
2
votes
1answer
133 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 ...
2
votes
0answers
112 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
260 views

Clearing distributed definitions from remote kernels

The documentation shows the following example to "Remove a distributed definition..." Oh, course this doesn't work without redefining the function prior to re distributing the definition. The ...
1
vote
1answer
45 views

Break out of ParallelDo

In a parallelised computation, I would like each kernel separately to break out of ParallelDo when it has finished going through the loop once. For a single kernel ...
1
vote
1answer
33 views

$IterationLimit and parallel computing

Short question: How can you set $IterationLimit for parallel computation? I thought just setting $IterationLimit = Infinity ...
1
vote
1answer
132 views

ParallelTable of ParametricNDSolve objects fail

There seems to be a problem with ParametricNDSolveValue togeteher with ParallelTable First we create a ParametricNDSolveValue object ...
1
vote
0answers
149 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 ...
0
votes
1answer
619 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
2answers
869 views

nested numerical integration: not valid limits?

I encountered an error when I was hoping for some Mathematica (8.0.4) magic sparing me to code up numerical integration, function approximation and root-finding myself. The broader context and the ...