gistfile1.txt

for iter=1:iterations
  for row_train=1:size(train_user,1)
      i=train_user(row_train);
      j=train_movie(row_train);
      r= train_rating(row_train);
      u_i=U(i);
      v_j=V(j);
      for p=1:nDims
          dJ_u=alpha*sum((transpose(u_i)*v_j-r)*transpose(v_j))+lambda*V(j,p);
          U(i,p) = U(i,p) - dJ_u;
          dJ_v=alpha*sum((transpose(u_i)*v_j-r)*u_i)+miu*U(i,p);
          V(j,p) = V(j,p) - dJ_v;          
      end
      
      train_predictions(i) = predict(u_i, v_j);
      valid_predictions(i) = predict(valid_user, valid_movie);
  end
      % train_predictions = predict(train_user, train_movie);
      % valid_predictions = predict(valid_user, valid_movie);

train_rmse = rmse(train_predictions, train_rating);
valid_rmse = rmse(valid_predictions, valid_rating);

fprintf('train rmse = %.4f, validation rmse = %.4f\n', train_rmse, valid_rmse);
end