Your function does not expect any input parameters.
Your function does not define a variable named mat . Therefore in order for the line
mat %mat is 6*6 matrix
to not be an error, then mat would have to be a function that you are invoking.
Then you do
E=inv(mat)
which is not inconsistent with the possibility that mat is a function... as long as the function returns a square matrix.
C=E*D
You have not defined any variable named D so in order for that line to be valid, D must be a function that you are invoking.
if bt==Swing
You have not defined any variable named bt so in order for that line to be valid, bt must be a function that you are invoking
mat(n,:) = [];
mat(:,n) = []
You have not defined any variable named n so in order for that line to be valid, n must be a function that you are invoking.
However... we have established that mat must be a function. It is potentially valid to invoke a function with two parameters, one of which is : . However, it is never valid for the output of a function to be the destination for assignment or deletion using [] .
