In working on a custom stock screener, I often need to run mathematica code like this:

{#, FinancialData[#, "DividendYield"]} & /@ Take[FinancialData["NYSE:*"], 30]

In this example, I've limited the result set to 30, but ideally I'd like to get the dividend yield for a much larger set.

This is a specific example of a more general problem I have with mathematica, which is that sometimes I need to run a large number of distinct network IO calls and this blocks further computations.

Is there some workaround for writing calls like this that won't block further computations? I am a fairly competent programmer and therefore can implement a system in my Mathematica code to compute results one at a time, but I am trying to avoid reinventing the wheel. I feel this must be a very common problem for Mathematica users who use the built in data sources/Wolfram|Alpha integration.

  • 2
    $\begingroup$ You can start two distinct kernels (or better: two instances of Mathematica front end too, if you're not on a Mac). But then they won't share variables. Alternatively you can evaluate in a subkernel. The relevant functions are ParallelSubmit and Parallel`Developer`QueueRun. $\endgroup$
    – Szabolcs
    Commented Mar 13, 2012 at 13:53
  • $\begingroup$ Thank you. I will look into the documentation for those calls and do some experimentation. $\endgroup$
    – achristi
    Commented Mar 13, 2012 at 13:56
  • $\begingroup$ I'll post a full answer tomorrow if I have time, or hopefully someone else will do it before that. $\endgroup$
    – Szabolcs
    Commented Mar 13, 2012 at 13:56
  • $\begingroup$ @Szabolcs one can start multiple mma frontends on a mac too (by directly exectuing the relevant file inside the Mathematica.app bundle) $\endgroup$
    – acl
    Commented Mar 13, 2012 at 14:30
  • $\begingroup$ @acl I never used a Mac, I've just been told that it's not easy to do it, and I wanted to avoid another comment about that. Two kernels should suffice anyway, I just prefer two front ends for these things in case I crash or (more likely) freeze one of them. $\endgroup$
    – Szabolcs
    Commented Mar 13, 2012 at 14:55

2 Answers 2


As Szabolcs mentions, the simplest way to do this is to start a new kernel and push this bulk of data acquisition to that kernel and let it run in the background. There are good examples in the documentation in tutorial/ConcurrencyManagingParallelProcesses.

For your specific case, here's an example following the above:

j = ParallelSubmit[{#, FinancialData[#, "DividendYield"]} & /@ 
   Take[FinancialData["NYSE:*"], 30]];

enter image description here

Out[3]= True

enter image description here

You can continue working as usual in your main kernel.


Parallel Kernels for separate Notebooks

Perhaps you simply want to run two kernels in parallel. You can do this by:

  1. Open Evaluation > Kernel Configuration Options... and set up more than one kernel.

  2. Assign a different kernel to each of two Notebooks using Evaluation > Notebook's Kernel

From there you can run your slow code in one Notebook and do your interactive programming in the other.

Mathematica graphics

"Dialogs" on a single Kernel

I guess the main point of my question is, if I'm launching an external command, even if I am waiting for feedback from it, it shouldn't take up a kernel's resources ... also not to mention that I'm being a complete jerk launching two kernels when we only have 2 on our network seat.

Perhaps your best option in that case is to run calculations in a kernel dialog while the background task is momentarily paused. On my system the shortcut key for Evaluation > Evaluate in Subsession is F7.

As an example try:

Do[Pause[1], {i, 50}];

And while it is running put the cursor in a separate cell containing:


And press F7.

Every time you select that cell and press F7 you should get the current value of i from the evaluating Do loop.

Mathematica graphics


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