--- a
+++ b/inst/nls_obj.m
@@ -0,0 +1,61 @@
+# Copyright (C) 2005  Michael Creel <michael.creel@uab.es>
+# 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+# usage: [obj_value, score] = nls_obj(theta, data, model, modelargs, nslaves)
+#
+# Returns the average sum of squared errors for a specified model
+# This is for internal use by nls_estimate
+
+
+function [obj_value, score] = nls_obj(theta, data, model, modelargs, nslaves)
+
+	n = rows(data);   
+
+	if nslaves > 0
+		global NEWORLD NSLAVES TAG
+		nn = floor(n/(NSLAVES + 1)); # number of obsns per slave
+    
+		# The command that the slave nodes will execute
+    		cmd=['contrib = nls_obj_nodes(theta, data, model, modelargs, nn); ',...	
+        	 'MPI_Send(contrib,0,TAG,NEWORLD);'];	
+
+		# send items to slaves
+		NumCmds_Send({"theta", "nn", "cmd"}, {theta, nn, cmd});
+
+		# evaluate last block on master while slaves are busy
+	  	obj_value = nls_obj_nodes(theta, data, model, modelargs, nn);
+
+		# collect slaves' results
+		contrib = 0.0; # must be initialized to use MPI_Recv
+	  	for i = 1:NSLAVES
+			MPI_Recv(contrib,i,TAG,NEWORLD);
+			obj_value = obj_value + contrib;
+		endfor
+
+		# compute the average
+  		obj_value = obj_value / n;
+  		score = "na"; # fix this later to allow analytic score in parallel
+
+	else # serial version
+    		[contribs, score] = feval(model, theta, data, modelargs);
+		obj_value = mean(contribs);
+    		if isnumeric(score) score = mean(score)'; endif # model passes "na" when score not available
+  	endif
+
+	# let's bullet-proof this in case the model goes nuts
+	if (((abs(obj_value) == Inf)) || (isnan(obj_value))) obj_value = realmax; endif
+
+endfunction