Hie, I've used GLM function, n try to get a convergence by using a while loop and break it when my absolute value between the 2 values is less than 1e-09. But i got this warning message, what does this mean? how should i correct my algorithm? my start value is 0.5. Error in if (abs((phi_0) - (phi_1)) < 1e-09) { : missing value where TRUE/FALSE needed Thankss -- View this message in context: http://www.nabble.com/glm-problem-tf3611346.html#a10091852 Sent from the R help mailing list archive at Nabble.com.