Minimax with Alpha Beta Pruning

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  • čas přidán 10. 03. 2017

Komentáře • 191

  • @bryanbocao4906
    @bryanbocao4906 Před 5 lety +218

    Great explanation! Some important notes as well:
    1) only in a Max node can update the corresponding alpha, so does Min for beta.
    2) v can only be returned up to its parent
    3) alpha and beta can only be passed down from its parent
    4) cut the current node from the tree whenever alpha >= beta
    In the graph on the right whiteboard, shouldn't all the alpha, beta are initialized as -infinity and infinity, respectively?
    At 13:07, for the completeness of the logic flow, I think we should set the beta to be 2 in the node(v=2, alpha=8, beta= ), then because alpha(8) > beta(2), we prune the right subtree.

    • @rampage14x13
      @rampage14x13 Před 5 lety +9

      all solid things to point out, thanks

    • @kingtqos1514
      @kingtqos1514 Před 5 lety

      It works like a charm, Thanks!

    • @superuser8636
      @superuser8636 Před 3 lety +6

      Yeah, this algorithm is total shit

    • @imnacho4127
      @imnacho4127 Před 2 lety +4

      beta would never assigned the value of two; the function would return before that variable assignment.

    • @kevin-lamquesnel9067
      @kevin-lamquesnel9067 Před rokem +1

      Thanks this helped me so much, you have no idea

  • @amellperalta
    @amellperalta Před 6 lety +149

    Excellent explanation! The video is clear, concise, and precise. We want more videos from you. Please teach us more about AI.

  • @RahulSam
    @RahulSam Před 7 lety +127

    You are a great lecturer, not many people can do this.

  • @XxBleedRainbowxX
    @XxBleedRainbowxX Před 5 lety +1

    Just wanted to thank you for your great videos! Watching them pre-exam to refresh and they're all very clear and informative

  • @sagnik3105
    @sagnik3105 Před 6 lety +12

    This definitely has to be the most thorough explanation I found on the topic. Thank you! :D

  • @nilsmartel2295
    @nilsmartel2295 Před 4 lety +2

    Every single time I see that you have uploaded a video about a topic, I lose all fear, that I'm not going to be able to understand it. This is not an exaggeration, you've helped me avoid so much confusion and desperation. Thank you so much John!

  • @jabodey
    @jabodey Před 6 lety +14

    THANK YOU SIR! I finally know alpha beta pruning!!! Your explanation was crystal clear. If you taught my AI course, I would never ditch class!!

  • @jonathancui3063
    @jonathancui3063 Před 4 lety +12

    As a self-learner, this video is by far the best explanation I've ever seen. Clean, concise, and to the point.

  • @benaya6
    @benaya6 Před 4 lety +1

    it's just amazing. all your videos are the definition of crystal clear explanation. perfect. I wish you'll do more videos

  • @GtaRockt
    @GtaRockt Před 3 lety +16

    Great teacher, got a B on my AI exam with your videos about tree search algorithms 👌 explained it way better in a couple of minutes than my teacher in an hour

  • @adamkawsara6881
    @adamkawsara6881 Před 6 lety +2

    Wonderful video. This helped a lot! Working through the example in real time and explaining your thought process as you went really helped make this click.

  • @pellekools6475
    @pellekools6475 Před 6 lety +2

    Great explanation! I already knew what steps to take, but it wasn't really clear why I should take those steps. It is clear to me now.

  • @syedahabali2450
    @syedahabali2450 Před 6 lety +4

    Respect to you sir. You explained it so well! I'm very grateful!

  • @AdityaRaj_Purohit
    @AdityaRaj_Purohit Před 5 lety +5

    One of the best video on youtube to understand Alpha Beta pruning.
    Want more video like this to get more understanding of AI.

  • @andrewweems9427
    @andrewweems9427 Před 6 lety +3

    Your videos are so concise and helpful. They're the only thing keeping my grade decent in my Intelligent Systems class.

  • @PauloViniciusMoreiraDutra

    the best explanation about minimax. You are a great professor. I watched a lot of videos about minimax algorithm, but only your video I understood clearly

  • @oshawastaken
    @oshawastaken Před rokem +2

    5 year later and still best video on alpha-beta pruning. Thank you sir.

    • @johnlevine2909
      @johnlevine2909  Před rokem +3

      Thanks for making me feel old! Very glad it's useful 😀

  • @Fionasfung
    @Fionasfung Před 2 lety

    This is the best video I have seen which explains the algorithm along with the graph.

  • @yashvats9703
    @yashvats9703 Před rokem +2

    He is god. He explained everything in just 13 minutes. I wish if I came across this video earlier it could have saved my time. Great teacher!!

  • @cookiejar3094
    @cookiejar3094 Před měsícem

    Your videos help me so much with my course, thanks!

  • @ManishSharma-cf3or
    @ManishSharma-cf3or Před 5 lety

    Awesome!! Seen most of your videos(Loved A* video too) and I must say that this topic was a bit tricky till I saw this ! You make it sound so simple

  • @rv.9658
    @rv.9658 Před 2 lety

    Watching this once saves me so much time that might've gone into reading through a textbook section on this particular algorithm

  • @mkamp
    @mkamp Před 7 lety +38

    Thanks. That was my nth video on that topic and this time it clicked. Thanks for taking the time to go through it so deliberately. :)

  • @GauravYadavdv31
    @GauravYadavdv31 Před 5 lety

    One of the best explanation, Thank you John Levine.

  • @mesosiderite4670
    @mesosiderite4670 Před 11 měsíci +3

    I want to thank you sir,
    you have done what my teacher was unable to do, a good explanation,
    it took me three days to understand this, and finally I understood thanks to this video

  • @hemmahbeast
    @hemmahbeast Před 5 lety

    Nice lesson, Biblo. The great eye watching you is pleased.

  • @TheZ0mi
    @TheZ0mi Před 5 lety

    Thank you Sir, after checking many videos on the same topic, your lecture makes me understand the topic.

  • @prasangsinghal262
    @prasangsinghal262 Před 5 lety +4

    He saved my exam. Thnxx sir for such a great explanation.

  • @dbnnoman5596
    @dbnnoman5596 Před 2 lety

    Thank You so much sir!
    God Bless you!

  • @ahlamalbimani2070
    @ahlamalbimani2070 Před 6 lety

    Thank you. I've seen many videos and could not understand until I saw this video. Many thanks for your clear explanation!!

  • @fejohnson
    @fejohnson Před 6 lety +2

    this is amazingly helpful for me! thank you sir for this explanation!

  • @meharabdullah8608
    @meharabdullah8608 Před 6 lety +2

    Fantastic explanation. No one on CZcams has ever explained this algorithm so nicely using it's pseudo code . Very nice Sir, Respect

  • @ArushitMudgal
    @ArushitMudgal Před 6 lety +3

    Watched it in approximately 9 minutes (X1.5 speed) and this has been the most precise and to-the-point explanation I have watched so far and believe me I have watched many. Thank you sir

  • @Daryn372
    @Daryn372 Před 5 lety

    Brilliant explanation. Just what I needed. Thank you.

  • @dadas7852
    @dadas7852 Před 6 lety +10

    This is the best video about this topic

  • @user-xp3me9ws9c
    @user-xp3me9ws9c Před 5 lety

    thank you for the video, it really helped me a lot doing my exam study!!

  • @_justinxu
    @_justinxu Před 3 lety

    Don't expect to instantly understand this topic, but your video did it. Thanks. :D

  • @nh1622
    @nh1622 Před 6 lety

    Really good!! Thanks for taking the time to explain it properly.

  • @dien2971
    @dien2971 Před 4 lety

    Thank you, sir. You are a great teacher!

  • @user-pr6cq3rs4x
    @user-pr6cq3rs4x Před rokem

    Thank you for this amazing video and explaination, not many have the ability to do this 🌸🖤

  • @dimmo15
    @dimmo15 Před 6 lety +1

    Thank you sir! I was wondering if there is a formula that can calculate the maximum number of nodes that can be pruned in a tree with a depth of d and a branching factor of b.

  • @jennachen1411
    @jennachen1411 Před 5 lety

    Thank you very very much! It takes a long time for me to understand the alpha-beta pruning .Luckly ,I find this vedio.

  • @SentryProductions1
    @SentryProductions1 Před 6 lety

    Would the -2 value not be pruned as we have a deep cut off situation ? We can see that Max will be = 8? Is there point in exploring -2?

  • @nassimmehalli7043
    @nassimmehalli7043 Před 5 lety +1

    an excellent teacher , thank's a lot. we'r waiting for more courses about AI :) Good luck

  • @nicolemb05
    @nicolemb05 Před 9 měsíci

    This is so helpful!! Thank you so much!

  • @shivamroy1775
    @shivamroy1775 Před 7 lety

    Thank You . You're an amazing teacher .

  • @ammarzorig2771
    @ammarzorig2771 Před 4 lety

    Thank you Dr

  • @johnphilipespia1167
    @johnphilipespia1167 Před 2 lety

    Thank you so much! You're the best!!

  • @sergiovasquez5643
    @sergiovasquez5643 Před 3 lety +1

    Great presentation of work. would it be possible to link the supplementary material associated with this lecture?

  • @vinicius2699
    @vinicius2699 Před 6 lety +1

    Damn, you are good. Thanks for helping

  • @dgglovesbb
    @dgglovesbb Před 8 měsíci

    Thank you so much!

  • @alexanderyau6347
    @alexanderyau6347 Před 5 lety +3

    Wow, this lecture helps me understand the alpha-beta algorithm, the pseudo code is very helpful to understand. Quite intuitive. Where is the link for the assignment?

  • @BeSharpInCSharp
    @BeSharpInCSharp Před 4 lety

    I have to admit you are the only one who could explain and impart knowledge to even the dumbest person like me. You are the great great teacher.

  • @xdxdxd1
    @xdxdxd1 Před 5 lety

    Amazing videos! Thank you!

  • @sashinthat3173
    @sashinthat3173 Před rokem

    Goated Explanation Sir!

  • @weidong1378
    @weidong1378 Před 5 lety

    Best video I've seen on the subject

  • @linh6360
    @linh6360 Před 4 lety

    thank you so much for the lecture.

  • @Tash98
    @Tash98 Před 5 lety

    The only explanation that made sense to me!

  • @TrangPham-kc7ft
    @TrangPham-kc7ft Před 3 lety

    Thank you so much for your video. It's really clear.

  • @joaquinvanloon7341
    @joaquinvanloon7341 Před 6 lety

    Great video, great explanatiom!

  • @pratyushshrivastava4362
    @pratyushshrivastava4362 Před 2 měsíci

    Great explanation!

  • @jebaanto7649
    @jebaanto7649 Před 3 lety

    Awesome explanation sir thanks from india

  • @tega2754
    @tega2754 Před 6 lety +2

    Thank you!!! :)

  • @mohamedibrahimhassan291

    loved the way you explaine

  • @jonesmukuta1910
    @jonesmukuta1910 Před 2 lety

    Good work right there!!!

  • @Jantol93
    @Jantol93 Před 2 lety

    The best explanation of alpha beta pruning. "If the value is greater than beta that means min is going to prefer the branch that lead to beta." That line made it click for me.

  • @guoshenli4193
    @guoshenli4193 Před 2 lety

    great explanation!!! Thank you!!!

  • @amirbaba9677
    @amirbaba9677 Před 2 lety

    this video was so helpful.
    thank you.

  • @ImranAkbarUK
    @ImranAkbarUK Před 5 lety +1

    very good Explanation Sir! :)

  • @simha3154
    @simha3154 Před 6 lety

    This is amazing. Thanks!

  • @madeline-qk3vg
    @madeline-qk3vg Před 11 měsíci

    this is life-saving sir thanks a lot ^-^

  • @hangchen
    @hangchen Před 4 lety

    OMG! Very very clear! I came from CS188 step by step.

  • @shantanulokhande3730
    @shantanulokhande3730 Před 7 měsíci

    Thank you so much sir. !!!!

  • @bangminh5712
    @bangminh5712 Před 6 lety

    Please make a video on Negamax as well, would be perfect if includes Transposition in the algorithm either. And thanks for the lesson, thank you.

  • @lenniegames3529
    @lenniegames3529 Před 6 lety

    Is it at all possible to see the slides you mention in the video? I've spent the past couple of days trying to figure out how to apply MiniMax with Alpha-Beta Pruning to my A-Level Chess AI, and I always seem to get bugs that shouldn't exist (I literally mean they shouldn't exist, not I don't know why they exist), Thanks

  • @bushrhaddad3141
    @bushrhaddad3141 Před 5 lety

    Very clear explanation, Thank you

  • @AntonAtef
    @AntonAtef Před rokem +1

    Great explanation 👌

  • @WickedChild95
    @WickedChild95 Před 6 lety

    Awesome video!

  • @ahsanshahid11
    @ahsanshahid11 Před 6 lety +2

    bunch of thanks (y)

  • @ApaDOCTOR
    @ApaDOCTOR Před 6 lety

    Thank you!

  • @hoomanjafari4633
    @hoomanjafari4633 Před 5 lety

    Thanks a lot, you made my day !

  • @j_m_b_1914
    @j_m_b_1914 Před rokem +1

    I must be missing something because the following scenario seems like a possible scenario where alpha beta pruning can discount a superior position down the road.
    In chess, isn't it possible to have a move sequence where moves 6 ply out may show an inferior score for white but if the line was analyzed further, we'd see that white might be able to force a mate by taking a material loss. Wouldn't alpha beta pruning possibly discount such a line by abandoning further computational depth for that line such that it would never be able to see that a temporary drop in maximization of white's score actually sets up for a win for white?
    I guess my question can be reduced to this:
    Is it possible for alpha beta pruning to discount a line that is temporarily inferior (low score) but a few moves further out we discover a forced mate? Could alpha beta pruning throw out the analysis for such lines?
    Also, the entire principle of the minimax algo (in my opinion) is the scoring we give specific positions based on what information has been learned about chess over the centuries. We rank certain material with specific scores and also certain positions with specific scores. If the methodology of scoring the current state of the chess game is imperfect, then the minimax algo may not always be 100% optimal in the search tree it explores based on those scores.
    Let me give a quick counter example to (hopefully) better illustrate my argument. In the game of chess, there is really only one ultimate score -- is there a sequence of moves from the current game position where white (or black if playing black) can force a checkmate of the opposing king. Every other analysis within the game is of no consequence if it doesn't lead to a line where the opposing king is checkmated (or if checkmating is not possible, the only other analysis of consequence is trying to draw the current game). A new chess engine called Oracle is created using hardware from thousands of years into the future. Oracle is able to analyze 100 ply within the game in a matter of microseconds. Oracle discovers a line where white sacrifices four pieces (let's say a pawn, a knight, a bishop and a rook) in order to force a mate on the opposing king approximately 20 moves out.
    Now in this example, wouldn't current engines stop processing this line after the first or second piece was lost because the minimax score / alpha beta pruning? The current engine might discount the sequence of moves and call the first sacrifice a blunder because it never processed this particular line deeper.
    I could be way off here because my knowledge of minimax with A/B pruning is incomplete -- that's why I'm throwing this out there for others with more experience. Is this a disadvantage of minimax with AB pruning?

  • @AGCrush
    @AGCrush Před 3 lety

    Great Explanation! Thanks alot.

  • @beri4138
    @beri4138 Před 3 lety

    Very good video. I will now attempt to code my own tic-tac-toe solver :)

  • @shehrozkhan9563
    @shehrozkhan9563 Před 2 lety

    Sirrr love your vids

  • @blackfromabove9383
    @blackfromabove9383 Před 3 lety

    Many thanks for explanation!

  • @abdellahi.heiballa
    @abdellahi.heiballa Před 5 lety

    great explaining prof

  • @shivamgarg437
    @shivamgarg437 Před 5 lety

    Do we always start with the root node as the maximum one?

  • @simoneditzzz
    @simoneditzzz Před rokem

    thanks man, you gave me a great favor

  • @danilocorreia5104
    @danilocorreia5104 Před rokem

    Thanks!

  • @aynurememmedova9436
    @aynurememmedova9436 Před rokem

    Thanks teacher...I watch your videos in Azerbaijan✨

  • @ElminsterWindwalker
    @ElminsterWindwalker Před 5 měsíci

    Thank you sir !

  • @cerocyka2810
    @cerocyka2810 Před 5 lety

    Cheers mate thanks!!

  • @kasunigamage3529
    @kasunigamage3529 Před 5 lety

    great explanation!! thanks a lot

  • @yashin2068
    @yashin2068 Před 5 lety

    it is a really nice explanation. thank u sir.

  • @matteomastandrea5680
    @matteomastandrea5680 Před rokem

    this mans single handedly getting me through AI

  • @nmt800
    @nmt800 Před 5 lety

    Awesome explanation. Upvote. Please make videos explain, all alogrithms Thanks!

  • @mursheduzzamanrakib260
    @mursheduzzamanrakib260 Před 6 lety +1

    Sir, would you mind making a series video for Artificial Intelligence... It will be more helpful...

  • @muhammadfawad1505
    @muhammadfawad1505 Před 6 lety

    Awesome Sir, @respect

  • @ShadowQuik
    @ShadowQuik Před 6 lety

    Awesome, very clear