code: public static void add(double alpha, DMatrixSparseCSC A, double beta, DMatrixSparseCSC B, DMatrixSparseCSC C,
                             @Nullable IGrowArray gw, @Nullable DGrowArray gx)
      {
          if( A.numRows != B.numRows || A.numCols != B.numCols )
              throw new MatrixDimensionException("Inconsistent matrix shapes. "+stringShapes(A,B));
          C.reshape(A.numRows,A.numCols);
  
          ImplCommonOps_DSCC.add(alpha,A,beta,B,C, gw, gx);
      }
docs: Performs matrix addition:<br>
  C = &alpha;A + &beta;B
  
  @param alpha scalar value multiplied against A
  @param A Matrix
  @param beta scalar value multiplied against B
  @param B Matrix
  @param C Output matrix.
  @param gw (Optional) Storage for internal workspace.  Can be null.
  @param gx (Optional) Storage for internal workspace.  Can be null.