Tip: use Build Matrix to assemble a 2D array by columns

[Neil Pate]

Normally if I have multiple 1D numeric arrays if I want to combine them into a 2D array to display as a table or write to file or whatever I used to Build Array and then transpose the 2D array, however I have discovered that the Build Matrix prim is actually configurable and defaults to assembling by columns.

Hooray!

This is probably old news to some people, but I share anyway for those that don't know 

[Omar Mussa]

That's interesting and I definitely have never thought of that.  Do you know what the differences are between the Matrix data type and Array data type?  I tried a couple of OpenG 2D array operations out and they all seem to work ok on the matrix.

[Neil Pate]

As far as I can tell a Matrix is just a typedef to a 2D double, there is nothing at all special about it. 

[hooovahh]

Yeah it's a neat feature but only works on the double (or numeric really) data types.  As for the Matrix data type, no idea really.  I mean I always assumed there is some performance improvements for those functions but then again why couldn't those improvements be implemented with normal 2D array of doubles as the data type and not be polymorphic like most other array functions?  Another nice function that is on the matrix palette that is polymorphic is the Matrix Size which returns the rows and columns both as scalars.  Why this isn't on the array palette I'll never know.