# Intuitive explanation of failed convergence for GLM

Sometimes the software complains about some matrix not being positive definite. Is it the singularity that's causing issues (because the iterative algorithm involves inverting matrices)? Also, what does this say about the data or model we're trying to fit?

• This is not strictly about GLMs, but if you're getting positive definite errors then this link may help. www2.gsu.edu/~mkteer/npdmatri.html – Eric Apr 15 '15 at 17:12