question: public ArrayRealVector ( ArrayRealVector v1 , RealVector v2 ) { final int l1 = v1 . data . length ; final int l2 = v2 . getDimension ( ) ; data = new double [ l1 + l2 ] ; System . arraycopy ( v1 . data , 0 , data , 0 , l1 ) ; for ( int i = 0 ; i < l2 ; ++ i ) { data [ l1 + i ] = v2 . getEntry ( i ) ; } }
target:  Construct a vector by appending one vector to another vector.