Day_00: Get set up

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Day_00: Get set up#

Turns out Julia uses base-1 indexing so I’m off to a rocky start ;)

  1. conda create julia

  2. conda install -c conda-forge julia

  3. enter Julia command with julia

  4. ] add IJulia adds Julia to the Python/conda environment (I think)

Playing with interactive code:

x = [1, 2, 3]

creates and displays the 3-element Vector{Int64}.

Trying to get dot product:

> x*x
ERROR: MethodError: no method matching *(::Vector{Int64}, ::Vector{Int64})

The default is a column vector, e.g. $3\times1$. So trying to multiply these together gives me a mismatched indices error.

Correcting the approach:

> transpose(x)*x
14

I can even reverse it and get the outer product

> x*transpose(x)
3×3 Matrix{Int64}:
 1  2  3
 2  4  6
 3  6  9

Wrapping up#

I didn’t spend a long time in Julia today, but I really like what I see so far. I still don’t understand how you would deal with environments/dependencies. It seems like you should be using the latest version of Julia (1.7.2 in this case) and the latest version of Jupyter (3.2.5). It looks like I should be using the pkg> mode to setup+manage environments within Julia REPL [Set up Julia environments].

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