Calculates the strength of a particular currency taking into account it's rate of change (% price change in a period) in all correlated and anti-correlated pairs. For instance, when looking for USD strength we will add ROC for USDCAD, USDCHF and USDJPY while subtract AUDUSD, EURUSD, GBPUSD and NZDUSD.
After ROC step, one can smooth the result using EMA, or MACD.
As the script needs to fetch values from multiple currencies it isn't the fastest one, but it gets its job done.
Important: Only major currencies (AUD, CAD, CHF, EUR, GBP, JPY, NZD and USD) are considered.