Data Duplication

rory's Avatar


25 Feb, 2015 06:17 PM

I am experiencing a very weird issue. I am relatively new to Nodebox 3, but I am have got a pretty good grip I think.

When grouping nodes together to form a network, the data is being duplicated many thousands of times. To be clear the network works fine, with the correct amount of data output. Then taking no other action than grouping it to a new network, the data becomes unmanageably slow.

I am running node box on a Mac Book Pro with Yosemite. I am new to Mac (like as of yesterday) and I never experienced this before on my PC. Any ideas?


  1. Support Staff 1 Posted by Frederik De Ble... on 25 Feb, 2015 07:21 PM

    Frederik De Bleser's Avatar

    You've encountered list matching!

    Grouping a network doesn't simply group the data. It creates a function that loops over all the input data you give it. So if you have, say, a list of 100 random numbers connected to a network containing a single rectangle, the network will be executed 100 times, each with the same single rectangle.

    This behaviour is actually quite useful since it allows you to put separate functionality in subnetworks. We use it for example to create a single element of a data visualisation, then having that element repeated for each input row of the visualisation.

    For more info on list matching and other NodeBox concepts, you can read the "how NodeBox works" page.

    Hope that helps,


  2. 2 Posted by rory on 25 Feb, 2015 08:36 PM

    rory's Avatar

    Thanks I am familiar with the looping element, and find it extremely useful! I found a work around. I'm perfectly sure you are right, I just need to digest it I guess. Anyway, this was the result: Cycle Flows on the TFL Road Network:

  3. Support Staff 3 Posted by Frederik De Ble... on 25 Feb, 2015 08:37 PM

    Frederik De Bleser's Avatar


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