question: public FrameBlock zeroOutOperations ( FrameBlock result , IndexRange range , boolean complementary , int iRowStartSrc , int iRowStartDest , int brlen , int iMaxRowsToCopy ) throws DMLRuntimeException { int clen = getNumColumns ( ) ; if ( result == null ) result = new FrameBlock ( getSchema ( ) ) ; else { result . reset ( 0 , true ) ; result . setSchema ( getSchema ( ) ) ; } result . ensureAllocatedColumns ( brlen ) ; if ( complementary ) { for ( int r = ( int ) range . rowStart ; r <= range . rowEnd && r + iRowStartDest < brlen ; r ++ ) { for ( int c = ( int ) range . colStart ; c <= range . colEnd ; c ++ ) result . set ( r + iRowStartDest , c , get ( r + iRowStartSrc , c ) ) ; } } else { int r = iRowStartDest ; for ( ; r < ( int ) range . rowStart && r - iRowStartDest < iMaxRowsToCopy ; r ++ ) for ( int c = 0 ; c < clen ; c ++ ) result . set ( r , c , get ( r + iRowStartSrc - iRowStartDest , c ) ) ; for ( ; r <= ( int ) range . rowEnd && r - iRowStartDest < iMaxRowsToCopy ; r ++ ) { for ( int c = 0 ; c < ( int ) range . colStart ; c ++ ) result . set ( r , c , get ( r + iRowStartSrc - iRowStartDest , c ) ) ; for ( int c = ( int ) range . colEnd + 1 ; c < clen ; c ++ ) result . set ( r , c , get ( r + iRowStartSrc - iRowStartDest , c ) ) ; } for ( ; r - iRowStartDest < iMaxRowsToCopy ; r ++ ) for ( int c = 0 ; c < clen ; c ++ ) result . set ( r , c , get ( r + iRowStartSrc - iRowStartDest , c ) ) ; } return result ; }
target:  This function ZERO OUT the data in the slicing window applicable for this block.