$ifcalculategain
出自 DDCC TCAD TOOL Manual
Lw is the thickness of quantum well in 
$ifcalculategain Lw
Example:
$ifcalculategain 6.00000e+01
Related commands:
$ifcalculategain,
$ifgainwithpol,
$ifonlycavitymode,
$calcavitygain,
$calcavQWLoc,
