Hello Rick,
temp1=(temp/x[1])##x[2];/*temp1 is a raw vector*/
tempexp=exp(-temp1);/*tempexp is a raw vector*/
tempexpsub=d1row-tempexp;/*tempexpsub is a raw vector results from subtract temexp from d1row (which is a raw vector of one's)*/
templog=log(tempexpsub);
during the calculations, sometimes there is an error for templog. I think , the program approximated the value o temexpsub when it is very small to 0 which causes problem to calculate the log.

I need to know how I can make SAS uses the actual results from tempexpsub matrix without any approximations or truncation of the values of this matrix to be able to calculate the log( tempexpsub) when the values of temexpsub are very small such that they close to zero?

Thank you