What does retrograde (vakri) mean in ePandit?
In ePandit, a planet is marked retrograde when Swiss Ephemeris reports negative longitudinal speed in sidereal mode. That is an observational/ephemeris flag, not a moral judgment about the planet.
How we detect it
Planet position calls request speed alongside sidereal longitude; retrograde means speed is negative. Transit stepping also tracks retrograde state changes for Mars, Mercury, Jupiter, Venus, and Saturn.