Prolog recursivly build list based on dot product -

hi have prolog function/predicate? takes dot product of 2 list. , use write function builds list of dot products list , list of list. basically, dot product called on each list in list of list function dot below , works.

dot([], [], 0). dot([head|tail], [head2|tail2], result) :-     prod = head * head2,     dot(tail, tail2, remaining),     result prod + remaining.  

this attempt @ function fails every-time try run it. can 1 help?

dotall([], [[]], [0]). dotall(x, [[head]|[tail]], result) :-     dotunit(x, head, prod),     result = [prod|result],     dotall(x, tail, result). 

to sum of goal, if passed in dotall([1,2,3],[[1,2,3],[4,5,6],[1,2,3]], what). back, what [15,32,15].

i know mouth full hope 1 can give me pointers on im going wrong. im new prolog.

the dotall predicate believe (from example) defined be:

dotall(vector, listofvectors, results) 

and says results list of dot product results obtained taking dot product of vector each vector in listofvectors.

reviewing dotall predicate:

dotall(x, [head|tail], [prod|result]) :-  % dotall of x [head|tail]                                           %   [prod|result] if...     dot(x, head, prod),                   % prod dot product of x w/head     %result = [prod|result],              % fail     dotall(x, tail, result).              % , result list of                                           %   dot products of x tail 

notes recursive case:

1. the result = [prod|result] fail since saying, i have result , it's same thing [prod|result] cannot true.
2. you can use third argument in clause, shown, express result list in recursive case ([prod|result])

then base case:

dotall(_, [], []).                       % dot product of                                          % empty list of vectors empty 

notes base case:

1. the first argument not [] because recursive predicate doesn't reduce first argument down empty list. first argument vector started used dot product elements in vector list (second argument). since don't care vector in base case, use _.
2. the second argument [], empty list since base case happens when we've exhausted list of vectors, list of lists. when end of lists of lists, have empty list ([]).
3. the third argument empty list [] not [0] because it's logical: if take dot product of vector empty vector list, should no results (an empty list []).

using above corrections:

| ?- dotall([1,2,3],[[1,2,3],[4,5,6],[7,8,9]], r).  r = [14,32,50] ? ;  no