docs: public static DMatrix2 extractColumn( DMatrix2x2 a , int column , DMatrix2 out ) {
          if( out == null) out = new DMatrix2();
          switch( column ) {
              case 0:
                  out.a1 = a.a11;
                  out.a2 = a.a21;
              break;
              case 1:
                  out.a1 = a.a12;
                  out.a2 = a.a22;
              break;
              default:
                  throw new IllegalArgumentException("Out of bounds column.  column = "+column);
          }
          return out;
      }