initialize_cores.m

function cores = initialize_cores(sz, ranks, varargin)
%initialize_cores Initializes cores using Gaussian distribution
%
%cores = initialize_cores(sz, ranks) returns a length-N cell with N cores,
%each with entires drawn iid from the standard Gaussian distribution. sz is
%a length-N vector with the sizes, and ranks is a length-N vector with the
%outgoing ranks.
%
%cores = initialize_cores(___, 'init_zero', init_zero) will just initialize
%all cores to zero if init_zero is true. Default is false.

% Handle optional inputs
params = inputParser;
addParameter(params, 'init_zero', false, @isscalar);
parse(params, varargin{:});
init_zero = params.Results.init_zero;

% Main code
N = length(sz);
cores = cell(N,1);
for n = 1:N
    R1 = ranks(n);
    if n == 1
        R0 = ranks(end);
    else
        R0 = ranks(n-1);
    end
    if init_zero
        cores{n} = zeros(R0, sz(n), R1);
    else
        cores{n} = randn(R0, sz(n), R1);
    end
end

end