question: public float innerProduct ( FeatureVector other ) { float cost = 0.0f ; for ( int i = 0 ; i < DENSE_FEATURE_NAMES . size ( ) ; i ++ ) cost += getDense ( i ) * other . getDense ( i ) ; for ( String key : sparseFeatures . keySet ( ) ) cost += sparseFeatures . get ( key ) * other . getSparse ( key ) ; return cost ; }
target:  Computes the inner product between this feature vector and another one.