code: public static double elementMin( DMatrix6 a ) {
          double min = a.a1;
          if( a.a2 < min ) min = a.a2;
          if( a.a3 < min ) min = a.a3;
          if( a.a4 < min ) min = a.a4;
          if( a.a5 < min ) min = a.a5;
          if( a.a6 < min ) min = a.a6;
  
          return min;
      }
docs: <p>
  Returns the value of the element in the vector that has the minimum value.<br>
  <br>
  Min{ a<sub>i</sub> } for all<br>
  </p>
  
  @param a A matrix. Not modified.
  @return The value of element in the vector with the minimum value.