function r = eval(obj, vars)% GPCONSTRAINT/EVAL  Implements EVAL command for GP constraints.%% Returns either a true (logical 1) or a false (logical 0) if all% GP variables are specified or a reduced GP constraint.%sz = size(vars);if( ~isa(vars,'cell') || sz(2) ~= 2 )  error('Second argument should be a cell array with 2 rows');end% check that all the gp variables are positive (implicit GP constraint)for k = 1:size(vars,1)  var_values = vars{k,2};  if any(var_values <= 0)    error('GP variables must have positive value.');  endend% evaluate different flavors of gpconstraintif( strcmp(obj.type,'<=') )  r = (eval(obj.lhs,vars)) <= (eval(obj.rhs,vars));elseif( strcmp(obj.type,'==') )  r = (eval(obj.lhs,vars)) == (eval(obj.rhs,vars));end