axisdir2vec.m

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% =========================================================================== %
%> @brief convert an axis and a direction to a vector
%>
%> @param axis axis (x, y, z) or number (1, 2, 3)
%> @param dir direction (positive, negative) or number (1, -1)
%>
%> @retval vec vector
%>
%> @code
%> vec = axisdir2vec("x", "positive") % returns [1, 0, 0]
%> vec = axisdir2vec(1, -1) % returns [-1, 0, 0]
%> @endcode
%>
%> %> @copyright see the file @ref LICENSE in the root directory of the repository
% =========================================================================== %
function vec = axisdir2vec(axis, dir)
 
% check the axis
if ischar(axis) || isstring(axis)
    axis = axis2num(axis);
elseif ~isnumeric(axis)
    error("The axis must be a number or a string")
end
 
% check the direction
if ischar(dir) || isstring(dir)
    dir = direction2num(dir);
elseif ~isnumeric(dir)
    error("The direction must be a number or a string")
end
 
% create the vector
vec = zeros(1,3);
vec(axis) = sign(dir);
 
end