Define the target, define the model's result from the last iteration and move the leaver by that deviation ratio and try again.

Here's a simple example which is not fully templated but is a good start

<file> creview USDomFDperPerson[com,ts][]

view USGDPConDollar[esect,ts][]

integer $trackStartYr = 2010 integer $trackEndYr = 2035 integer $lastScnYr getobjinfo (USGDPConDollar[esect,ts][2], $lastScnYr; info=sequenceEnd, dim=time)

keep varTarget[tsTrack]

say (“Iteration: ”, $fbViewIteration) if ($fbViewIteration == 1)

string $importEIAData
buildstring ($importEIAData, $home, "/primaryData/energyConsumption/EIARefCase")

say ("Importing EIA GDP to track on")
local EIAUSGDPConDollarTotalx[ts] =  changeseq (copyshape (sum (USGDPConDollar[esect,ts][2]; \
	dim=econSector)); \
	dim=time, start=2008, end=$trackEndYr)

EIAUSGDPConDollarTotalx[ts] = import (; dataFormat="odometer", delimiter=",", firstLine=5, lastLine=5, ignoreExtraCols=on, \
	rowTitles=on, file=$importEIAData/AEO2011-Industrial_Sector_Macroeconomic_Indicators-AEO2011_Reference_Case.csv)
	
local EIAUSGDPConDollarTotal[ts] = EIAUSGDPConDollarTotalx[ts] * 1e9

varTarget[tsTrack] = extract (EIAUSGDPConDollarTotal[ts]; time:$trackStartYr..$trackEndYr)

endif

local varLI[tsTrack] = extract (sum (USGDPConDollar[esect,ts][2]; dim=econSector); time:$trackStartYr..$trackEndYr) local devRatio[tsTrack] = varTarget[tsTrack] - varLI[tsTrack] / varTarget[tsTrack] !table (devRatio[tsTrack], varTarget[tsTrack], varLI[tsTrack]; overlay=on) local creVarLI[com,ts] if ($fbViewIteration == 1)

creVarLI[com,ts] = USDomFDperPerson[com,ts][2]

else

creVarLI[com,ts] = USDomFDperPerson[com,ts][3]

endif

local numNotConv[] = sum (boolgt (devRatio[tsTrack], $fbViewTolerance); dim=all) integer $numNotConv getobjinfo(numNotConv[], $numNotConv; info=dataElement) if ($numNotConv == 0) or ($fbViewIteration == $fbViewMaxIters)

mumble ("   numNotConv = ", $numNotConv, " at iteration ",$fbViewIteration, " stopping due to ")
if ($numNotConv == 0)
	say ("convergence")
else
	say ("maximum iterations")
endif		

! Set the outputs
USDomFDperPerson[com,ts][3] = creVarLI[com,ts]

quit(0)

else

say ("   numNotConv = ", $numNotConv, " at iteration ",$fbViewIteration, " continuing")

endif

local multiplier[ts] = extend (min (max (devRatio[tsTrack], -0.5), 0.5) + 1.0; dim=time, end=$lastScnYr) USDomFDperPerson[com,ts][3] = creVarLI[com,ts] * multiplier[ts]

quit(1) </file?