code: public SDVariable norm2(String name, SDVariable x, int... dimensions) {
          return norm2(name, x, false, dimensions);
      }
docs: Norm2 (L2 norm) reduction operation: The output contains the L2 norm for each tensor/subset along the specified dimensions:<br>
  out = sqrt(sum_i x[i]^2)
  
  @param name       Output variable name
  @param x          Input variable
  @param dimensions dimensions to reduce over
  @return Output variable