question: public static MatrixBlock rexpand ( MatrixBlock in , MatrixBlock ret , double max , boolean rows , boolean cast , boolean ignore ) throws DMLRuntimeException { int lmax = ( int ) UtilFunctions . toLong ( max ) ; if ( ! ignore && in . getNonZeros ( ) < in . getNumRows ( ) ) throw new DMLRuntimeException ( "Invalid input w/ zeros for rexpand ignore=false " + "(rlen=" + in . getNumRows ( ) + ", nnz=" + in . getNonZeros ( ) + ")." ) ; if ( in . isEmptyBlock ( false ) ) { if ( rows ) ret . reset ( lmax , in . rlen , true ) ; else ret . reset ( in . rlen , lmax , true ) ; return ret ; } if ( rows ) return rexpandRows ( in , ret , lmax , cast , ignore ) ; else return rexpandColumns ( in , ret , lmax , cast , ignore ) ; }
target:  CP rexpand operation (single input, single output)