I’m going around in circles and I’m convinced that the problem comes from the platform engine for calculating values in a loop.

attached 2 screenshots explaining the phenomenon. The code below is the heatmap indicator that records the value of each indicator for each calculated period. I have voluntarily painted in red a period value to check (the period 200), applying the indicator “wave PM” on the graph with the same period can thus control the values returned by the loop.
We see that nothing matches. The “wave PM” indicator marks extremes beyond the value 0.90, while none of them return this type of extreme value when they are calculated inside the WHILE WEND loop. They are all well below, in orders of magnitude that have nothing to do …
In short, if someone has time to check what I wrote, I’m ready to answer questions 🙂 Thank you!

// ---
startperiod=20 //start period of the loop
maxscale=500 //end period of the loop
Step=10 //period step of the loop
BandsDeviations=1.25 //bands deviation (WAVE PM)
Chars= 100 //period of observation (WAVE PM)
// ---

psize=pointsize
BandsPeriod=startperiod //first period to test is..startperiod

while BandsPeriod<=maxscale do

 // --- wave PM indicator calculation
 Dev = std[BandsPeriod]*BandsDeviations
 Dev1 = square(Dev / psize)

 //temp=sqrt(average[chars](dev1))*pointsize
 temp=sqrt(summation[chars](dev1)/chars)*psize
 if temp<>0 then
  temp=dev/temp
 endif

 if(temp>0) then
  iexp=Exp(-2*temp)
  returnNum= (1-iexp)/(1+iexp)
  osc= (returnNum)
 else
  iexp=Exp(2*temp)
  returnNum=(iexp-1)/(1+iexp)
  osc= (returnNum)
 endif

 // -----

 result=osc

 r=0
 if bandsperiod=200 then
  r=255
 endif

 drawtext("#result#",barindex,BandsPeriod,dialog,bold,10)coloured(r,0,0)

 BandsPeriod=max(startperiod,BandsPeriod+Step) //increase indicator period for next loop iteration
wend

return startperiod,maxscale

For people enjoying color on their charts.. RSI heatmap is working fine.
Colors shade from red (oversold) to green (overbought) from period 20 to 500 on a 1-hour and 5-minutes charts. Not the subject of that topic, but information are valuable IMO. Trend following or mean reversion valuable infos in that heatmap.

You can make very pretty pictures if you take an average or RSI and Stochastic combined.

//PRC_RSI and Stochastic multiperiods HeatMap | indicator
//Plot an heatmap of the RSI range of periods
//04.07.2019

// --- settings
startperiod=2 //start period of the loop
maxscale=500 //end period of the loop
Step=10 //period step of the loop
// --- end of settings

iPeriod=startperiod //first period to test is..startperiod

while iPeriod<=maxscale do

// --- indicator calculation
osc = (stochastic[iperiod,5] + rsi[iperiod])/2
// -----

result=osc

R = max(0,50+(200-(result-50)*12))
G = max(0,50+(200+(result-50)*12))

drawtext("■",barindex,iperiod,dialog,bold,18) coloured(min(r,255),min(g,255),0)

iPeriod=max(startperiod,iPeriod+Step) //increase indicator period for next loop iteration
wend

return startperiod,maxscale