vec2axisdir.m

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% =========================================================================== %
%> @brief convert a vector to an axis and a direction
%>
%> @param vec vector
%>
%> @retval axis axis (1, 2, 3)
%> @retval dir direction (1, -1)
%>
%> @code
%> [axis, dir] = vec2axisdir([1, 0, 0]) % returns "x", "positive"
%> [axis, dir] = vec2axisdir([-1, 0, 0]) % returns "x", "negative"
%> @endcode
%>
%> %> @copyright see the file @ref LICENSE in the root directory of the repository
% =========================================================================== %
function [axis, dir] = vec2axisdir(vec)
 
arguments
    vec (1,3) double
end
 
% check the vector
assert(sum(abs(vec)) == 1, "The vector must be a unit vector")
assert(max(abs(vec)) == 1, "The vector must align with an axis")
 
% find the axis
axis = find(vec);
 
% find the direction
dir = sign(vec(axis));
 
end