docs: public static void fill(DMatrixSparseCSC A , double value ) {
          int N = A.numCols*A.numRows;
          A.growMaxLength(N,false);
          A.col_idx[0] = 0;
          for (int col = 0; col < A.numCols; col++) {
              int idx0 = A.col_idx[col];
              int idx1 = A.col_idx[col+1] = idx0 + A.numRows;
  
              for (int i = idx0; i < idx1; i++) {
                  A.nz_rows[i] = i-idx0;
                  A.nz_values[i] = value;
              }
          }
          A.nz_length = N;
          A.indicesSorted = true;
      }