Escala exponencial

Pega esta expresión en la propiedad “Scale”:

if (num_keys >1 && key(num_keys).time > time && key(1).time <= time){
     k = nearest_key(time).index;
     if (key(k).time <= time) {
     a = k;
} else {
     a = k-1;
}
     b= a+1;
     a_val = key(a)[0];
     b_val = key(b)[0];
     a_time = key(a).time;
     b_time = key(b).time;
     if(a_val == 0) {
         a_val = .1;
     }
     if (b_val == 0) {
         b_val = .1;
     }
     x = Math.log(b_val) / Math.log(a_val);
     exp = linear(time, a_time, b_time, 1, x);
     val = Math.pow(a_val, exp);
     [val, val];
}else{
     value;
}