function  A = o1fit(xyz,rgb)
% RBG values are expected to be between 0 and 1
% function that calculates the transformation matrix between xyz
% and rgb: i.e. A(rgb) = xyz, where A is a 3x3 matrix. We
% transpose both sides, then use slash and transpose the result:
% i.e. (rgb)'A' = xyz', A' = rgb'\xyz';

A = (rgb'\xyz')';

