# Questions tagged [parallelization]

Questions on parallel computing in Mathematica.

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### LaunchKernels generates a mysterious error message

In Mathematica v. 11.1.0, on OS X 10.11.6, I get the following error message when I LaunchKernels: ...
257 views

### ParallelTable much slower than Table on RandomReal with arbitrary precision

So I was trying a very simple example (Mathematica 11.0.1) ...
575 views

### Parallel Table and CUDA

I have a large matrix computation and I use Parallel table, which launches 4 Kernels. I do not have a GPU. Will having a GPU help me in Launching more Kernels and solve the problem faster? All my ...
123 views

### How to successfully put a ParallelDo loop inside a Do loop?

I'm trying to set up a ParallelDo loop inside of a Do loop, however I'm running into issues. Here is a very simplified toy model ...
45 views

### Parallel number systems don't scale well

I'm working on Residue Number System. This is basically a set of relatively coprime integers, let's say $\{3,4,5\}$ and we define its range to be the product of the moduli, i.e. $M=3\cdot4\cdot5=60$. ...
91 views

### Speed up performance of nested function computations

I'm trying to create a model for intensive computations for a homomorphic encryption scheme. The core of my problems is a series of function calls ...
89 views

### How to do parallel computation when using LinearProgramming function?

I have a LP problem which contains 2n+3 variables with 4n+6 inequality constraints. I was trying to use Mathematica's LinearProgramming function. When n is small, like less than 30, it gives outcome ...
1k views

### How many cores can I use with my license?

From what I have been told, Mathematica licenses come with a limited number of cores it can run on in parallel. I have 24 cores on my machine and when I do ...
118 views

### How can multiple kernels update a shared Association object?

In the examples below, the variable status is an Association object that is supposed to be shared by three concurrent kernels. ...
148 views

### ParallelMap performs badly inside function

I'm trying to parallelize a very simple code that performs a stochastic gradient descent optimization (on a dual core cpu w. hyperthreading, so 4 parallel kernels). I use ParallelMap to compute the ...
62 views

### “ParallelDo” does not calculate the function well

Now, I'm solving utility maximization problem. ...
267 views

### Difficulty in parallelizing function using package (MCMC)

Difficulty in parallelizing Packages using DistributeDefinitions Context I am trying to parallelize some parameter estimation using MCMC. As a test run I expect ...
92 views

### How to catch Print and Monitor message dialog?

Context I am trying to parallelize a function which is verbose, and which as a consequence Mathematica does not seem to treat in parallel when doing something like ...
334 views

### Do SetSharedVariable/SetSharedFunction ruin the benefits of ParallelTable?

Edit: I changed the sample code to get at my question better. Slowdown due to accessing a shared variable is a much more relevant issue (to me at least) than slowdown due to writing to a shared ...
118 views

### Does Abort not work for ParallelTable with SetSharedVariable?

I find that often Abort (command-. on Mac) sometimes does not work if ParallelTable is running. Here's a simple example: ...
88 views

### Mathematica using all available cores, but not speeding up calculation as much as expected

This is a follow-up question to my previously posted question on how to get Mathematica to use all available cores to do a parallel calculation. I resolved this by rewriting the code in terms of a <...
178 views

### Mathematica not using all cores available

I am trying to run a ParallelDo loop in Mathematica, that uses NSolve to solve an equation for a number of different input ...
103 views

### How to speed up code in ParallelDo loops?

I have a piece of code that I'm trying to run in a ParallelDo over 32 kernels. Using a normal Do loop in a kernel Mathematica ...
681 views

### Parallelize Map and ParallelMap

Bug introduced in 8.0 and fixed in 11.2 It is stated in the documentation that Parallelize[Map[f, expr]] is equivalent to ...
103 views

### Forwarding Monitor Parallel computation

I'm experimenting with training neural networks. Map[NetTrain[NetInitialize@#, trdata] &, {net1, net2}] shows the Training Progress monitor on each ...
168 views

### When using Java objects through JLink, how can I multitask the objects?

I use Mathematica 11.0.1 on Windows 10 and have a Java class which acts as a 'facade' for a headless browser (PhantomJS). In Mathematica I instantiate the class through JLink as follows: ...
122 views

### How to start a new thread on mathematica

I need to start a new thread inside a mathematica function. My example is about image aquisition and processing. ...
654 views

### Get::noopen: Cannot open CloudObjectLoader error when running Mathematica on remote cluster

I have been running Mathematica on a remote cluster for quite sometime. Recently, any jobs that call LaunchKernels[] for parallelization return the error Get::...
455 views

### Parallelization inside a module: Proper use of local variables

I have the following Module which includes a ParallelDo call. Unfortunately, ParallelDo is ...
99 views

### SetOptions in parallel computation

I have NIntegrate[] inside a ParallelDo[] loop. Outside the loop I set some options for the integration using ...
164 views

### Using different master kernel in the same notebook

In my notebook, I have to call another file, let's say 'program.m' that defines functions, let's say F[] of whom result c I need ...
542 views

### Parallel calculation is 5 times slower than the non-parallel one

I have used code from Tell ParallelMap[] to use just specific kernels : ...
228 views

### Print output of parallel kernels to console

Is it possible to print all the output (inside a Print[] command) of a parallelized computation to the console? I can't find a control for this. I find that my computer can handle printing to the ...
173 views

### Run multiple NDSolve Simultaneously

In a previous question I asked how to speed up the performance for NDSolve for a single evaluation. With the help provided, the solution is much faster. Now, I'd like to run the same code in different ...
98 views

### What is the most effective way to reassign values in an array based on their positions

I have to reassign values in a big array many times and it turned out to be the most time consuming in my program. The best way I could figure out is this ...
67 views

### ParallelTable: How to see which cells finished calculating?

I have a code to generate a table with a computationally very expensive function f[x,y]. I run the code on a cloud server, that is, from the command line without ...
170 views

### ParallelTable and Table give different results

I am trying to parallelize a table operation, but I find that the table is not the same with and without the parallel function. I have looked at this question, but I cannot transfer it to my own ...
283 views

### Can I run more than two kernels simultaneously on my MacBookAir laptop?

I'm running Version Number 10.0.1.0 with Platform Mac OS X x86 (32-bit, 64-bit kernel). I have two Mathematica programs running using "Local" and "Alternative Local Kernel". Is this the most I can ...
59 views

### Parallelization and assumptions

I'm having a simple problem. Here is the code Table[Simplify[DifficultFunction[i],assumptions], {i,DifficultSet[1, 2]}] the correct and simplified answer is ...
67 views

### Wolfram cdf player does not support parallel computing?

I tested the following. ...
90 views

### Programmatically access the data from the Parallel Kernel Status window

I want to show the parallel kernel status within a notebook, and not in the separate Parallel Kernel Status window. How can I programmatically access the Performance Measurements data shown in the ...
635 views

### Parallelize simple for loop

I am trying the following code: ...
55 views

### Parallelize evaluation of initialization cells

I have a notebook with about 20 initialization cells. Evaluating all of them takes a few minutes. Mathematica uses only one core for this. In my case, the cells are all independent so it should be ...
141 views

### How can I cleanly distribute definitions of system functions?

I have a package that redefines a system symbol, and I am struggling to find a clean solution that will ensure that those redefinitions will still work inside a parallelized environment. The core ...
338 views

### gridMathematica on cluster with PBS Pro

I'm running my script (say "cluster.m") on the University cluster with PBS Pro installed. The script uses simple Parallelize like this: ...
104 views

### ParallelTable Automatically kill MathKernel

At the moment I continously encounter the problem that while using ParallelTable the process kswap needs all the memory, while the four running MathKernels receive almost zero %Memory, which slows ...
128 views

### ParallelSubmit executes only on one kernel

I'm trying to use Parallesubmit to run some calculations in parallel, but it looks like all the calculations are evaluated at one kernel. Consider this example: <...
165 views

### Does ParallelTable work with Co-Processors?

I have programs which can not use CUDA (graphic cards), but can run perfectly in parallel using ParallelTable (mainly symbolic transformations). Now I wonder, ...
270 views

### Register “initialization code” to run on any newly started parallel kernel

Is it possible to register a some "initialization code" to be run on any newly started parallel kernel? This would be similar to how ParallelNeeds registers a ...
731 views

### Restarting Mathematica automatically

I run a large computation in a loop. At each cycle of the loop I produce large arrays that I save on a disk. At each cycle I would like to Quit Mathematica and ...
48 views

### How can I speed up the evaluation of my equations?

Calculation of eigenvalues and eigenvectors in dependence of the parameters ...
74 views

### Variable not available in kernel despite DistributeDefinitions`

I am following this answer to evaluate certain cells in a separate kernel. I have created a separate kernel called K2 and have the following MWE: ...
282 views

### clear variables on parallel kernel

Short question: what is the proper way to clear a variable on a given kernel ? AND how can I ensure that the memory will indeed be freed subsequently ? Full question. Let me elaborate this question ...