I have been using a DSYEV, for some time. My instructor told me to calculate how much time does DSYEV take to diagonalise a $N \times N $.I know, in our case matrix M is symmetric. Standard procedure is Similarity Transformation $P^{-1} M P$. Gives $(Matrix)^{3}$.I saw $3(Matrix)+(Matrix)^{2}$.
How much time does DSYEV take to diagonalise a $N \times N $
fortran;lapack