# Vensim Help

 Navigation: Reference Guide > Functions > Dynamic Functions SMOOTH3(input,delay time) 3rd order exponential SMOOTH SMOOTH3I(input,delay time,initial value) 3rd order exponential SMOOTH with Initial

Returns a 3rd order exponential smooth of the input.  Equivalent to the equations:

SMOOTH3=INTEG((LV2-SMOOTH3)/DL,

input)

LV2=INTEG((LV1-LV2)/DL,input)

LV1=INTEG((IN-LV1)/DL,input)

DL=delay time/3

SMOOTH3I=INTEG((LV2-SMOOTH3I)/DL,

initial value)

LV2=INTEG((LV1-LV2)/DL,

initial value)

LV1=INTEG((IN-LV1)/DL

initial value)

DL=delay time/3

NOTE The SMOOTH3 function does not conserves material when the delay time is changing.  It is intended to be used for information delays.

Units: SMOOTH3(units,time) --> units
SMOOTH3I(units,time,units) --> units

The input units match the output units.  The units of delay time must match those of TIMEĀ  STEP.  For SMOOTH3I units for the initial value must match those of the input.

Example

S = STEP(10,40)

SS = SMOOTH3(S,20)

SSI = SMOOTH3I(S,20,5)