I believe I found the answer, thanks to http://sourceforge.net/mailarchive/message.php?msg_id=20510733 On Fri, May 27, 2011 at 1:06 AM, Sergey Dymchenko <kit1980_at_...6...> wrote: > Hi! > > I'm very new to Prolog and ECLiPSe. > > I can't understand how to use custom functions in searches. > > For example, I have a list A and I want to find all variants of list B > such that maximum elements in vector product A*B is not greater than > 20. > The code I wrote: > > > :- lib(ic). > > max_vector_product(L1, L2, R) :- > (foreach(E1, L1), > foreach(E2, L2), > foreach(Product, Product_list) > do > Product is E1 * E2 > ), > R #= max(Product_list). > arithmetic_function(max_vector_product/2). > > solve :- > A = [7, 8, 1], > > length(A, N), > length(B, N), > B :: 0..3, > max_vector_product(A, B) #=< 20, > labeling(B), > writeln(B), > fail. > > > But I get an error with the code: instantiation fault in *(7, > _135682{0 .. 3}, _135754) > How to deal with that? > > And the code works, for example, if I just want to limit maximum of B to 2 - > max(B) #=< 2, > but not with my custom function (and the custom function works on its own). >Received on Thu May 26 2011 - 22:48:43 CEST
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