$ifimpactusepureExy

$ifimpactusepureExy make the program to calculate the impact ionization using pure Ex and Ey instead of using $\mathrm{\nabla }Ec$ and $\mathrm{\nabla }Ev$ for electron and hole impact ionization.

For more details on impact ionization, please see $ifimpact_ion or new command $ifimpact_new, $ifimpactuseEfgradiant