destinations at the end of each distinct pass insteadthe notion of pass becomes diffuse the method was invented by gilstad [ - and called polyphase sort it is first illustrated by an example using three sequences at any timeitems are merged from two sources into third sequence variable whenever one of the source sequences is exhaustedit immediately becomes the destination of the merge operations of data from the non-exhausted source and the previous destination sequence as we know that runs on each input are transformed into runs on the outputwe need to list only the number of runs present on each sequence (instead of specifying actual keysin fig we assume that initially the two input sequences and contain and runsrespectively thusin the first pass runs are merged from and to in the second pass the remaining runs are merged from and to etc in the endf is the sorted sequence fig polyphase mergesort of runs with sequences second example shows the polyphase method with sequences let there initially be runs on on on on and on in the first partial pass runs are merged onto in the endf contains the sorted set of items (see fig fig polyphase mergesort of runs with sequences polyphase is more efficient than balanced merge becausegiven sequencesit always operates with an - -way merge instead of an / -way merge as the number of required passes is approximately log