The dollar index (DXY) is a synthetic index. It is calculated as a weighted geometric mean of the dollar's value compared only with "basket" of 6 other major fiat currencies which are:
Euro (EUR), 57.6% weight
Japanese yen (JPY) 13.6% weight
Pound sterling (GBP), 11.9% weight...
The dollar index has dropped from ~81.25 down to ~79.75 over the last ~3 weeks. Both gold and silver are roughly flat (down actually) in that same time frame. Wierd.