OPENS APRIL 18, CERT 15, 115 MINS The Armenian Holocaust of 1915 remains one of the most shrouded and fiercely disputed incidents in 20th-century history. The Turkish authorities continue to deny it ever happened. Others claim that 1.3 million Armenians died in the genocide. These tragic events form the backdrop to Atom Egoyan's new film. Egoyan approaches his material in subtle and oblique fashion. Rather than simply make a movie about the Holocaust, he has structured his story as a film within a film. Charles Aznavour says a contemporary, Canadian-based director whose new movie is based on a book about the Holocaust. This is a family melodrama, a polemical essay, a celebration of the life and work of abstract expressionist Arshile Gorky (who was caught up in the bloodshed) and a would-be historical epic. By providing so many sub-plots and secondary characters, Egoyan risks losing sight of his own ostensible subject matter. However, even if it does pull in too many directions, Ararat has a passion and intensity sometimes missing from the director's other work.