The Kernel is the back-end application thread that does the actual evaluation of all non-graphical expressions. It can be accessed directly through the console but is more commonly working behind the scenes to power the Notebook Interface. Multiple Kernels may be run for parallel computation.

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37
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5answers
18k views

How do I clear all user defined symbols?

Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?
37
votes
4answers
2k views

Aborting evaluation when the memory exceeds a certain limit

Sometimes when generating a lot of data the memory usage shoots beyond its physical realm and my laptop freezes. There is no way to stop Mathematica when this happens. Task manager (or its equivalent ...
37
votes
4answers
5k views

Saving data inside a notebook so that I don't have to run it again?

Piggybacking on this, I am somehow not fully convinced that I can't save data generated by a calculation in a mathematica file so that when I re-launch said file, I wouldn't have to run my ...
13
votes
2answers
1k views

Automatically load packages at startup

I'm a physics student and I try to simplify my day with Mathematica. Every time I use Mathematica I need Div[], Grad[], ...
26
votes
1answer
840 views

Why are there two separate MathKernel processes running when I start up Mathematica 9?

When I start the Mathematica 9 Front End, and check the list of running processes, I see two separate MathKernel processes. If I only start the kernel, without a front end, then there's only one ...
17
votes
2answers
403 views

MathKernel doesn't return all Messages

In Mathematica I run this command: Plot[Sin[x], {x, 1, 15}, GridLines -> error] It generates a Plot with this error message: A GridLines specification ...
11
votes
2answers
340 views

ScheduledTask with scoped variables. Working with timed evaluation

I guess I have to try harder and focus more but timed evaluation always frustrates me. I will show the issue on simple example of delayed trigger. ...
7
votes
0answers
2k 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 ...
9
votes
2answers
351 views

Seeking strategies to deploy a function securely without a front end

Background I have a fuction, which calculates an analytic solution to a multi-dimentional geometry problem. The function takes a list of real numbers (typically less than a dozen) and outputs a ...
13
votes
1answer
690 views

Space-efficient null space of sparse array

I have a roughly 100,000 × 3,000 matrix (as a SparseArray) that I'd like to find the kernel (null space) of. It has about 500,000 nonzero entries, all -1 or 1. ...
15
votes
2answers
295 views

How can I access a variable in one evaluator from another evaluator?

I have two notebooks, each with a different kernel. Is there a way to grab the value of a variable in KernelA from KernelB?
24
votes
2answers
1k views

Kernel crash after idle in version 10.0

Bug introduced in 10.0.0 and fixed in 10.0.2 In version 10.0, when I leave the Mathematica section idle for some time (of order an hour), the kernel quit automatically. The syntax highlighting is ...
17
votes
1answer
501 views

Quit the Kernel and start new session automatically

The question is how to quit the kernel, start a new session automatically, and to be able to run such procedure from e.g. Button. This is especially useful when ...
8
votes
2answers
825 views

Keep MathKernel Running In Background - Speed Up Execution Time

Background: I'm running Debian on a remote server with Mathematica installed. I have several dozen small mathematica files that are run in cron jobs at unpredictable intervals and updated based on a ...
6
votes
3answers
321 views

Can one launch a Player Pro kernel independently of the front end

This question follows on from my earlier one, Seeking strategies to deploy a function securely without a front end. As it pursues a different track to solve the same problem it seemed distinct enough ...
7
votes
1answer
333 views

CompilationTarget->“C” crashes the kernel

Major deviation from my original post I realize that the long code I originally had was very discouraging to debug and did not attract any answers. So I have decided to revamp this question ...
7
votes
1answer
2k views

Improving NDSolve speed for heavily stiff problems

Having looked around the intergoogles and Mathematica.SE, I thought I'd pose a question with a minimum working example. Here is the situation I am trying to improve: I am solving a 4th order non ...
14
votes
1answer
1k views

Kernel Management

I would like to run a computation in one NoteBook that will take 2 hours. Could I assign this Notebook a specific Kernel so I can run computation in other Notebooks ?
11
votes
1answer
928 views

Scheduling Mathematica scripts to run from a command line [duplicate]

I want to run Mathematica "jobs" on a daily/weekly basis to do system maintenance and as part of daily processing operations. What is the best way to do this?
6
votes
1answer
542 views

Remote Kernel configuration works in v9 but not in v10

I have both v9 and v10 currently installed on my computer (Windows 7). For reasons that are not entirely clear, if I create a new remote kernel in one version, it is accessible to the other; however, ...
5
votes
3answers
1k views

Remote Mathkernel: SSH encountered a networking error while launching kernel Error code = 1

I have a problem concerning the connection to a remote kernel via ssh on a vpn. I found a working configuration in this question: Connection to remote kernel can not be established - No specific ...
9
votes
1answer
1k views

How to stop the Kernel from running wild?

How to abort or stop this (accidently large defined) SparseArray production? s = N[SparseArray[Table[{2^i, 4} -> i, {i, 30}]]] Alt+. or Alt+, seem to give ...
4
votes
1answer
91 views

ListVectorPlot crashes kernel after two evaluations

I am currently trying to produce many plots by using ListVectorPlot, but every time I re-evaluate my code, the kernel crashes. I have set $HistoryLength=0 and ...
29
votes
3answers
317 views

How can I evaluate untrusted Mathematica code in a sandbox?

Is there any way to build a sandbox to evaluate untrusted Mathematica expressions in order to prevent them from having (malicious or accidental) harmful side effects? Context: I'm developing a system ...
21
votes
2answers
3k views

Unsaved notebook is crashing: is there any way I can save the state of the MathKernel before I kill it?

So I'm in the middle of generating some plots and all of the sudden the frontend goes dead and I haven't saved my work. I'm using Mathematica 8 in MacOS X. The MathKernel process is still running and ...
11
votes
2answers
740 views

Evaluator option for Mathematica Scripts

I have mathematica with many additional kernels besides Local ( e.g., core1, core2, core3, core4 ... ) added through Kernel Configuration Options. I have been running multiple copies of a simulation ...
8
votes
3answers
1k views

Generating figures over remote connection (using terminal)

Recently I've been making movies by having Mathematica create figures and then I combine all of them together using ffmpeg. The problem now is that my macbook is ...
11
votes
3answers
337 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 ...
6
votes
1answer
533 views

Accessing data on local machine from remote kernel

I have a remote kernel on a server that I would like to use to process some data. The connection works, i.e, I'm able to use the local front end and the remote kernel. However, I cannot figure out how ...
6
votes
1answer
418 views

Using “Raw MathLink Connections” to create a “Kernel Object”

Mathematica 8.0.0: I am stuck trying to get a Mathematica Mathlink connection from my Windows computer working that should connects to Linux over network (or vice versa) and then launches a Kernel on ...
7
votes
1answer
799 views

Creating and editing new stylesheets

I'm trying to create a stylesheet, but the process has become painful. I'm sure that this has to do something with resetting something in Mathematica everytime I make changes to the stylesheet. To ...
6
votes
2answers
251 views

Difference between Evaluation>>Quit Kernel and Quit[]

What is the difference between Evaluation >> QuitKernel and Quit[]? Both seem to quit the kernel (and clearing all ...
4
votes
2answers
316 views

Keep kernel running for execution of scheduled task

How can I keep a kernel running until all scheduled tasks have completed? For example upon running the following script bazinga.m: ...
4
votes
1answer
831 views

Connection to remote kernel can not be established - No specific error shown

I was trying to set up a remote kernel using Mathematica 8, a Debian server and a Mac OSX 10.8 client. First I configured a VPN connection between server and client and went through all the basic ...
8
votes
2answers
174 views

Obtain input expression from history without evaluating

I typed and evaluated an expression, but deleted it from the notebook. For instance, suppose it was In[1]:= Round@SessionTime[] Out[1]= 2 I now want to retrieve ...
7
votes
2answers
241 views

Communication between local kernels

this is my first post but you have already helped me so many times that I have to start by saying thanks a lot! I have a really long calculation to do, and I have used the Evaluation->Kernel ...
6
votes
2answers
322 views

Why does Mathematica stop when run in the background in command line mode?

If I try to start a Mathematica script in the background from the command line, like this: math -script someFile.m & then the process gets automatically ...
2
votes
1answer
109 views

Kernel crashed after $RecursionLimit = Infinity

$RecursionLimit = Infinity; T[n_, k_]:= T[n, k] = If[n == 0 || k == 1, 1, T[n, k-1] + If[n<k, 0, T[n-k, k]]]; Table[T[n!, n], {n, 1, 9}] Without ...
2
votes
1answer
241 views

Render dynamic Graphics objects static

As was discussed in the comments of another question (MathLink Graphical Output (Plots) to File), Graphcis objects produced by commands such as ...
10
votes
2answers
382 views

Why LibraryLink function crashes at a second time?

Bug introduced in 9.0 or earlier and fixed in 10.3 Update As Todd Gayley commented under halirutan's answer, this is a bug. I'm trying link one of Lapack's function to Mathematica through ...
10
votes
2answers
286 views

Return partial result when MemoryConstrained aborts NDSolve

I use NDSolve to solve a large set (~400) of coupled ODEs. Sometimes, the memory (~4GB) gets filled up, and my computer becomes impossible to work with, because it ...
7
votes
1answer
78 views

Launch Front End from .NET MathKernel and return result to .NET

Is it possible to launch a front end and open a notebook from a .NETLink kernel and return a result from the notebook to .NET? In the code below "x" appears in the .NET textbox after 10 seconds but ...
3
votes
1answer
417 views

kernel Local crashes during the course of a For loop

I want to find the minimum of the function r[x,p] subject to the constraint w[x,p,t]==0 (t ...
3
votes
1answer
241 views

How to correctly disconnect from the kernel?

I'm connecting to and disconnecting from the kernel but I'm doing something wrong. I crash the text formatting in the terminal and got some warnings. There are some instructions to connecting to the ...
3
votes
2answers
880 views

Is there a way to get user input when running a script on a Linux terminal?

I have access to a node of a Linux cluster, on which Mathematica is installed. However, I do not have access to a Linux GUI. Typically I write and test Mathematica scripts on my Windows personal ...
2
votes
0answers
76 views

Is there a way to specify which kernel is used to import files (SOLVED)?

Following up on a previous question in which I encountered a memory leak in the JSON importer I have created a SandBox script that will run the Import and analysis on a separate kernel, which be ...
2
votes
1answer
69 views

Unprotect fails the first time, works on second pass [duplicate]

I am redefining some of the standard math functions. I know this is dangerous, so I am trying to be extra careful. (For instance, in the redefinitions, I make sure to only match a custom head) The ...
2
votes
2answers
135 views

Change Temporary Directory

How to change the value of $TemporaryDirectory ? I need to change it because there is not enough space on the C drive and the calculation seems to stop after a while !
2
votes
0answers
553 views

Runaway MathKernel!

I was running a simulation and everything went south (my fault, stupid coding error). So I quit the kernel. Everything was running very slowly, as if it were doing some kind of large calculation. ...
1
vote
0answers
20 views

License not released after kernel is stopped for KernelTimeLimit reached?

Using webMathematica, doing massive tests of our functions (each call can take from 0 to 15 seconds). After a while we started getting lots of 403 Forbidden errors. webMathematica.log: ...