Calculate the points on a variance-covariance ellipse.
Conlev is a small utility to calculate the points on a variance-covariance ellipse, specifically written for plotting the covariance of bulk modulus K, and its pressure derivative K'. Before running the program, you need to know the values of K and K' from the EoS refinement, along with their variances and covariance. Use a value of 2.30 for the confidence level (del-chi2) for the ellipse corresponding to the equivalent of a 1sigma error bar.