function z = baddet(A)
% BADDET   z = baddet(A)
%   an m! method for computing determinants of m x m matrices
%   don't try it if A is larger than 10 x 10

if length(size(A)) ~= 2
  error("only works on matrices, not vectors or tensors"), end
if diff(size(A)) ~= 0
  error("only works on square matrices"), end

if columns(A) == 1
  z = A(1,1); % easy case
  return, end
if columns(A) == 2
  z = A(1,1) * A(2,2) - A(1,2) * A(2,1); % also easy case
  return, end  

z = 0;  s = +1;
for k = 1:columns(A)
  % minor = [A(2:end,1:k-1) A(2:end,k+1:end)];  recurse:
  z = z + s * A(1,k) * baddet([A(2:end,1:k-1) A(2:end,k+1:end)]);
  s = s * -1;
end