That's happened to me too :). The definition for dcf is indeed hidden in a closed cell somewhere in that notebook. Here's the definition itself:

dcf = Blend[System`PlotThemeDump`$ThemeDefaultMatrix, #1] &

This is grabbing one of the default color schemes—the one used for MatrixPlot, for example—and making it available for your use. (It's also converting it from a scheme with discrete colors into a continuous one.)

Hi Jon! Totally fair to ask questions beyond the scope of the course—especially if you kindly indicate that you're aware that you're doing that ;).

My understanding is that (currently!) CoreML can be used when running a neural net (or using a built-in function that uses neural nets "transparently" to the end user), but it can't be used when training a neural net.

I can't say that I'm aware of MLX, but a quick look through some internal information seems to indicate that it is in use in at least some places!

Just click Submit, and we will receive your completed quiz. Certificates will be issued after the deadline of November 7. Thanks for your participation!

Nope, we're putting these on live every day at 11AM CST; nothing is prerecorded here. The interaction comes from people using the Q&A pane. I'm not positive what that looks like as an audience member, but in my view it's right next to the Chat section:

I am having a little trouble with the Machine Learning Basics notebook with regards to the option def for the ColorFunction - when I run the code the output is all red - when I change the option to one of the builtin options such as "AuroraColors" the output looks good - I am wondering about where or how the def was defined. I think I am missing something simple. Thanks

In Notebook WSG72-1-MachineLearning.nb, the Veronoi mesh input cell includes within the With[...] instruction an iconized ChatTechColors . When I try to get information about ChatTechColors by mousing over it and selecting the left icon, there is no information in the popup window. Selecting the right icon yields this message: "ChatTechColors: The source notebook cannot be opened." If possible, please make the source code and documentation available.