test_lbincoeff

(tmp_for_tar/misc/test_lbincoeff.m)

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 Last modified: April 2001

Cross-Reference Information

lbincoeff        tmp_for_tar/misc/lbincoeff.m
sayif        tmp_for_tar/misc/sayif.m

Listing of file tmp_for_tar/misc/test_lbincoeff.m

## Author:        Etienne Grossmann  <etienne@isr.ist.utl.pt>
## Last modified: April 2001

if ! exist ("verbose"), verbose = 0; end
if ! exist ("inspect"), inspect = 0; end
sayif (verbose, "\n             test_lbincoeff\n\n");

cnt = 1;
ok = 1;

N = 100;			# Check that all exp (lbincoeffs(N,K)) is
				# bincoeffs(N,K) for 0 <= k <= n <= N

[nn,kk] = lotr (N+1);		# n,k pairs
nn--; kk--;
L = length (nn);

sayif (verbose, "Going to compute %i bincoeffs ...", L);
bc = bincoeff (nn,kk);
sayif (verbose, "done\n");

sayif (verbose, "Going to compute %i log bincoeffs ...", L);
lbc = lbincoeff (nn,kk);
sayif (verbose, "done\n");

err = (bc - exp (lbc)) ./ bc ;

if max (abs (err)) > sqrt (eps)
  ok = 0;
  if verbose || inspect
    printf ("not ok %i error is big\n",cnt);
  end
  if inspect, keyboard; end
elseif verbose
  printf ("ok %i\n",cnt);
end
cnt++;

				# Check that sum of exp (lbincoeffs(n,k))
				# for n == 1000 and k = 0:n is 2^n
				# (bigger values give problems to 2^n and exp)
N = 1000;
sayif (verbose, "Summing up exp (lbincoeff (%i,1:%i))\n",N,N);

err = (sum (exp (res = lbincoeff (N,1:N))) - 2^N)/2^N;

if abs (err) > sqrt (eps)
  ok = 0;
  if verbose || inspect
    printf ("not ok %i error is big\n",columns (shs));
  end
  if inspect, keyboard; end
elseif verbose
  printf ("ok %i\n",cnt);
end
cnt++;

cnt--;
sayif (verbose && ok, "All %i tests ok\n",cnt);