I am trying to wrap my head around the LinearMaps.jl package. In their documentation they have only two examples and I am stuck at the first one.
# Define a linear map from a matrix and one from a function (?)
A = LinearMap(rand(10, 10))
B = LinearMap(cumsum, reverse∘cumsum∘reverse, 10)
# Possible operations
3.0A + 2B
A + I
A*B'
[A B; B A]
kron(A, B)
How does LinearMap() work when its argument(s) are functions? For instance the cumsum() function doesn't work on its own as it requires the dims argument, so I am completely puzzled as to what this is doing.