What does return value of Analyze Command represent mathematically exactly?

[MikeITExpert]

I am just curious what return value of Analyze Command represents mathematically exactly?

Does it mean that there is definitely no solution for the input system of equations given the convergence tolerance?

or

It means that there might be some, but OpenSees couldn't find any?

Please let me know regards,

[mhscott]

It can mean a couple of things. The solution of Ax=b failed (e.g., singular matrix) or the solution algorithm, e.g., Newton failed to converge or diverged.