The file matrix.txt contains the following information:

Total center-of-mass energy #Calculated near the midpoint of the fitted 
                            # kinetic energy range
Matrix dimension: D

Chi-squared value

Number of data in the energy bin

I   L   J   index     parameter   #Corresponding to Covariance Matrix Row 1
I   L   J   index     parameter   #Corresponding to Covariance Matrix Row 2
...
...
...
I   L   J   index     parameter   #Corresponding to Covariance Matrix Row D-1
I   L   J   index     parameter   #Corresponding to Covariance Matrix Row D
Covariance Matrix Row 1
Covariance Matrix Row 2
...
...
...
Covariance Matrix Row D-1
Covariance Matrix Row D

Where I =isospin, L = angular momentum, J = total spin

If the index = 1 , the parameter is the phase shift
If the index = 3 , the parameter is an angle rho such that cos( rho ) = eta

Angles are given in degrees and eta is the usual elasticity parameter.