code: func gfInverse(a gfElement) gfElement {
  	if a == gfZero {
  		log.Panicln("No multiplicative inverse of 0")
  	}
  
  	return gfExpTable[255-gfLogTable[a]]
  }
docs: // gfInverse returns the multiplicative inverse of a, a^-1.
  //
  // a * a^-1 = 1