Hello! This is my first time posting here, so please bear with me.

My spreadsheet looks like this:
Column A: Regularly sampled data (cyclical, goes from minima to maxima in about 15 days and then back to a minima in another 15 days)
Column B: Time of occurrence for each row of column A, increasing one hour every row and continuing for about 1.5 years.

Column C: Maxima and minima extracted from column A
Column D: Time of occurrence for each maxima and minima
Column E: Number of hours between maxima and minima
Column F: Pi/Column E, Number of radians per hour for each maxima/minima cycle

Column G: Uses INDEX(C:F, MATCH(B2, D2:D53, 1), 4) to find radians per hour for each row of column B
Column H: Finds number of hours since the start of a cycle for every row of column B, resetting back to zero after each maxima and minima

I then want to assign each data point in Column A an angle in radians. If I do this by multiplying G*H, then each cycle in Column A starts at the minima with 0 radians, climbs to maxima where it reaches Pi, and then drops back to 0 radians at the start of the next cycle. I want it to start at 0 radians, climb to Pi, and decrease from Pi back to 0 radians, and then back up to Pi and so on. I can't for the life of my figure out how to get excel to do this!

Thanks in advance for any help!