private long getIdxOffsetFor ( final int i ) { checkRowOrder ( ) ; int idx = 0 ; int offset = 0 ; for ( final iHistogramRowSeq row : rows ) { final int sz = row . size ( ) ; if ( offset + sz > i ) { break ; } offset += sz ; idx ++ ; } return ( ( long ) idx << 32 ) | ( i - offset ) ; }
Finds the index of the row of the ith data point and the offset in the row .