List.iter (fun (r,l) -> r := l) (List.combine p.deltas (List.hd p.trail)) ;
prerr_endline("Now trying var="^string_of_var var^" i="^string_of_int i);
aux (i+1)
List.iter (fun (r,l) -> r := l) (List.combine p.deltas (List.hd p.trail)) ;
prerr_endline("Now trying var="^string_of_var var^" i="^string_of_int i);
aux (i+1)