[FEATURE] Target attack of PI-FGSM

[CHENBIN99]

✨ Short description of the feature [tl;dr]

Thank you for this great work that allows us to quickly and easily call each adversarial attack method!

As discuss in Issus#143, you have made quick work of the PI-FGSM non-targeted attack method.

Now that I have obtained the relevant paper of PI-FGSM targeting attacks, I wonder if you might consider adding it to torchattacks

Thank you so much for all your hard work!

💬 Detailed motivation and codes

paper

[rikonaka]

Hi @CHENBIN99 , it looks like these are two different approaches in here PIM and here PIM++. PIM does not support target attack, but PIM++ does.

Should I call it PIM as the original author did or PI-FGSM? But then the paper calls it PI-FGSM, which is indeed confusing.

Image from here.

[CHENBIN99]

As I understand it, PI-FGSM can be called PIM (Patch-wise Method) and likewise PI-FGSM++ can be called PIM++ (Patch-wise Method ++).
PI-FGSM++ can be considered as a successor to PI-FGSM with the addition of the target attack

[rikonaka]

Hi @CHENBIN99 , the PI-FGSM++ has been add to torchattacks.

[CHENBIN99]

Thanks for your efficient work!