RE: Rounding errors

From: "diane r mould" <drmould@attglobal.net> Subject: RE: Rounding errors Date: Fri, 23 Mar 2001 13:09:22 -0500 Dear All A few minor notes on the suggestions made by others: I too have found that increasing the number of sig digits can sometimes result in NONMEM converging successfully when a previous run with fewer significan digits terminated due to rounding errors. Sometimes, however, the increased number of significant digits still results in a termination due to rounding errors. If this happens, the resulting parameters from the control stream with the higher number of significant digits can be used as intitial estimates for a new model. I would then reduce the number of significant digits back to 3 and this may converge successfully. With regard to the variance covariance structure, if the termination is due to over parameterization in this part of the model, I have found that use of a BAND matrix structure and appropriately re-organizing the matrix can often get past the termination error but still retain much of the off-diagonal information. Best Regards Diane