I'm reading Trefethen's Spectral Methods in Matlab.
When creating the differentiation matrices,
column= [ anything ]
D=toeplitz(column,column([1 N:-1:2]))
Can someone please explain what exactly is happening inside the [ ... ] in the line above.
I understand you are shifting the columns but I don't understand that syntax.
Are you referring to the 2nd line with: [1 N:-1:2] ?
If so, lets look at an example, let N = 4 and just calculate:
N = 4; [1 N:-1:2]
ans =
1 4 3 2
Which creates a vector with the first element being 1. Next the values start at 4 and decrement by 1 until you reach 2.
This is a basic Matlab syntax, [a:b:c], creates a vector with starting value a, increasing (or decreasing if -b) to c in steps of b.
Is this what you are referring to?