docs: public static void constraintMatrix6x6( DMatrixRMaj L_6x10 , DMatrixRMaj L_6x6 ) {
  
  		int index = 0;
  		for( int i = 0; i < 6; i++ ) {
  			L_6x6.data[index++] = L_6x10.get(i,0);
  			L_6x6.data[index++] = L_6x10.get(i,1);
  			L_6x6.data[index++] = L_6x10.get(i,2);
  			L_6x6.data[index++] = L_6x10.get(i,4);
  			L_6x6.data[index++] = L_6x10.get(i,5);
  			L_6x6.data[index++] = L_6x10.get(i,7);
  		}
  	}