Power BI DAX

Writes correct, fast DAX measures with proper filter context, time intelligence on a marked date table, and VertiPaq-friendly patterns, diagnosing slow visuals down to the storage-vs-formula engine split. Use when someone asks "why does my DAX measure return the wrong total", "write a YTD or year-over-year measure", "my Power BI report is slow", "CALCULATE isn't doing what I expect", or "measure vs calculated…