Re: [Gretl-users] removing nan and inf from a matrix

This is great! Actually, I was looking for something like this for a while. Could anybody explain the single elements of this command, please? It does not look very intuitive to me. Or is there reference in the gretl guide on this? M = isnan(M) ? 0 : M Thank you. Artur Am 25.07.2013 11:28, schrieb Allin Cottrell: > On Tue, 23 Jul 2013, Logan Kelly wrote: > >> I need to take the log difference of a matrix, i.e. log(M[2 >> rows(M):,]/M[1:rows(M)-1,]). Unfortunately, M has elements >> equal to zero. I need to replace the nan's and inf's with >> 0's. This almost works >> >> M = isnan(M) ? 0 : M >> >> but does not remove inf's. Any sugestions? > > Is this calculation actually legit? Assuming it is, then > > <hansl> > matrix M = muniform(15,2) > M[2,2] = 0 > M[3,2] = 0 > matrix ldM = log(M[2:rows(M),] - M[1:rows(M)-1,]) > ldM = isnan(0 * ldM) ? 0 : ldM > print M ldM > </hansl> > > This relies on the IEEE 754 rules: both 0*inf and 0*(-inf) > return nan. > > Allin Cottrell > _______________________________________________ > Gretl-users mailing list > Gretl-users(a)lists.wfu.edu > http://lists.wfu.edu/mailman/listinfo/gretl-users >