The transpose of a matrix is a matrix whose column is equal to the row of The inverse of a matrix is a matrix such that is the identity matrix The trace of a matrix is the sum of the entries on the main diagonal upperleft to lowerright The determinant is computed from all the entries of the matrix and is nonzero precisely when the matrix is nonsingular that is when the equation always has a unique solution The matrix rank is the number of linearly independent columns and is equal to three precisely when the matrix is nonsingular A number is an eigenvalue of if there is some nonzero vector such that ; the vector is called an eigenvector In the result the row of the eigenvector array is an eigenvector of unit length associated with the eigenvalue in the eigenvalue array