Re: [Gretl-users] Hansl Help

On Wed, 30 Nov 2011, Riccardo (Jack) Lucchetti wrote: > On Wed, 30 Nov 2011, Sven Schreiber wrote: > >> On 11/30/2011 10:55 PM, Henrique Andrade wrote: >>> Dear Hansl experts, >>> >>> I would like to write a Hansl code but unfortunately I'm out of >>> creativity :( >>> I have a binary series with blocks of 0 and 1. Something like >>> >>> X=(0,0,0,1,1,1,1,1,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1). >>> >>> Here are the steps I need do follow: >>> >>> (1) Find the number of 1-blocks; >>> (2) Calculate the average number of observations inside these blocks. >>> >>> In my hypothetical example, the X series, I have two blocks, and these >>> blocks have an average of 8 observations (five observations in the first >>> block and eleven observations in the second block). >>> >> >> Just a quick thought: you could take the (serial/first) difference of >> your series and count the occurrences of -1, which indicates how many >> times you have a 01 pattern. And each 1 in the difference indicates the >> position of a 10 pattern (or vice versa, depending on whether you take >> left-to-right or right-to-left differences). The position indices help >> you determine how many ones you have in between, i.e. in each block. >> >> But your problem in general does look like unpleasant details to code. > > Building on Sven's idea: call your binary series y. Then, > > <hansl> > series chg = diff(y) > chg[1] = (y[1] == 1) > scalar n_blocks = sum(chg==1) > scalar avg_len = sum(y) / n_blocks > </hansl> > > I think this ought to work. Here's another approach -- not so elegant in that it involves a loop, but it prepares a vector of block lengths, in case that might be wanted. <hansl> matrix X={0,0,0,1,1,1,1,1,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1}' matrix B = {} scalar blen = 0 scalar n = rows(X) loop i=1..n -q if X[i] == 1 blen++ if i == n || X[i+1] == 0 B |= {blen} blen = 0 endif endif endloop printf "Found %d blocks, average length %g\n", rows(B), meanc(B) </hansl> Allin Cottrell _______________________________________________ Gretl-users mailing list Gretl-users(a)lists.wfu.edu http://lists.wfu.edu/mailman/listinfo/gretl-users