Updates to cp_df_als add AtA to make faster

btas/generic/cp_df_als.h

@@ -387,6 +387,14 @@ namespace btas {
       factors_set = true;
       this->A = init;
     }
+
+    void use_old_factors(){
+      factors_set = true;
+    }
+
+    std::vector<Tensor> get_close_to_end_factors(){
+      return close_to_end_factors;
+    }
    protected:
     Tensor &tensor_ref_left;   // Left connected tensor
     Tensor &tensor_ref_right;  // Right connected tensor
@@ -398,6 +406,7 @@ namespace btas {
     std::vector<size_t> dims;
     std::vector<Tensor> init_factors_left;
     std::vector<Tensor> init_factors_right;
+    std::vector<Tensor> close_to_end_factors;
 
     /// Creates an initial guess by computing the SVD of each mode
     /// If the rank of the mode is smaller than the CP rank requested
@@ -699,8 +708,9 @@ namespace btas {
         for (size_t i = 0; i < ndim; ++i) {
           normCol(i);
         }
-      } else{
-        for(size_t i = 0; i < this->ndim; ++i) {
+      }
+//      else{
+        /*for(size_t i = 0; i < this->ndim; ++i) {
           auto &a_prev = this->A[i];
           ind_t col_dim = a_prev.extent(0);
           ind_t prev_rank = a_prev.extent(1), smaller_rank = (prev_rank < rank ? prev_rank : rank),
@@ -717,21 +727,22 @@ namespace btas {
             auto old = a_prev.begin();
             for (auto iter = view.begin(); iter != view.end(); ++iter, ++old) *(iter) += *(old);
             a_prev = a;
-          }
+          }*/
           // Optional add a bump to the previous factors
 //          } else{
 //            for(auto & el : a_prev)
 //              el +=  distribution(generator);
 //          }
-        }
-        A.pop_back();
+        //}
+        /*A.pop_back();
         Tensor lambda(rank);
         lambda.fill(0.0);
         this->A.push_back(lambda);
         for (size_t i = 0; i < ndim; ++i) {
           normCol(i);
-        }
-      }
+        }*/
+//      }
+      factors_set = true;
       ALS(rank, converge_test, max_als, calculate_epsilon, epsilon, fast_pI);
     }
 
@@ -760,7 +771,7 @@ namespace btas {
       // intermediate
       bool is_converged = false;
       bool matlab = fast_pI;
-      Tensor MtKRP(A[ndim - 1].extent(0), rank);
+//      Tensor MtKRP(A[ndim - 1].extent(0), rank);
       leftTimesRight = Tensor(1);
       leftTimesRight.fill(0.0);
 
@@ -787,12 +798,15 @@ namespace btas {
           }
           contract(this->one, A[i], {1, 2}, A[i].conj(), {1, 3}, this->zero, this->AtA[i], {2, 3});
         }
-        is_converged = converge_test(A);
+        is_converged = converge_test(A, this->AtA);
+        if(count == 10)
+          close_to_end_factors = this->A;
       }while (count < max_als && !is_converged);
 
       // Checks loss function if required
       detail::get_fit(converge_test, epsilon, (this->num_ALS == max_als));
       epsilon = 1.0 - epsilon;
+      this->AtA.clear();
       // Checks loss function if required
       if (calculate_epsilon && epsilon == 2) {
         // TODO make this work for non-FitCheck convergence_classes