LU decomposition - An Example Calculation

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  • เผยแพร่เมื่อ 26 ก.ย. 2024

ความคิดเห็น • 248

  • @brightsideofmaths
    @brightsideofmaths  3 ปีที่แล้ว +11

    Download the pdf version: tbsom.de/s/ov
    Watch my whole linear algebra course: tbsom.de/s/la
    If you have a non-square matrix and need row exchanges, watch here: th-cam.com/video/E3cCRcdFGmE/w-d-xo.html

  • @hardy4331
    @hardy4331 4 ปีที่แล้ว +274

    I should be giving my university fees to this guy.

    • @MalamIbnMalam
      @MalamIbnMalam 3 ปีที่แล้ว +20

      LOL I agree, it's shameful for what we have to pay for at Graduate school and Undergraduate

    • @eeshaanmj8656
      @eeshaanmj8656 2 ปีที่แล้ว

      Then give

    • @STgauss3268
      @STgauss3268 ปีที่แล้ว

      Contribute him in steady...

  • @MisterAdri85
    @MisterAdri85 3 ปีที่แล้ว +104

    My theacher taugh me something with elimination matrix that i still can't understand. This is 10pm, i have my exams at 8am tomorrow and you just saved me a lot of points on my grade. Thanks

    • @brightsideofmaths
      @brightsideofmaths  3 ปีที่แล้ว +26

      Good luck tomorrow. Don't forget to cite me during the exam ;)

    • @MisterAdri85
      @MisterAdri85 3 ปีที่แล้ว +13

      @@brightsideofmaths haha sure will !

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      How did your exam end up going?

    • @MisterAdri85
      @MisterAdri85 2 ปีที่แล้ว +2

      @@PunmasterSTP It's been a while i can't remember, but i didn't fail that's for sure cuz i entered my third year in engineering studies

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      @@MisterAdri85 That's awesome! How are you liking your third year?

  • @notgeo3912
    @notgeo3912 2 ปีที่แล้ว +41

    This is honestly genius and simple! All the lectures out there, at least the ones I've seen, give me the whole L11, L12.... stuff and if not that, the formulas which are too much to remember and use in the exam but this is a straight-up time saver to me as I can do row operations fluently! Thanks a ton!

  • @jamespapakyriakopoulos6187
    @jamespapakyriakopoulos6187 4 ปีที่แล้ว +39

    watched this video before my university lecture and it helped 10x more

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      How have your studies been going?

  • @kaif7312
    @kaif7312 4 ปีที่แล้ว +41

    LOL, while my professor for graduate level algorithm course spent entire 2 1-hour lectures on explaining this.

    • @vychuck
      @vychuck 3 ปีที่แล้ว +12

      Actually, your professor had to explain the foundation ogfGauss elimination to get LU done, i.e why you readily get this example.

  • @agbandanalistowel4737
    @agbandanalistowel4737 3 ปีที่แล้ว +5

    You're a genius man. You've saved me from long processes to go through. Thumbs up

  • @PunmasterSTP
    @PunmasterSTP 2 ปีที่แล้ว +2

    LU decomposition? More like "You are a man on a mission"...to spread knowledge and wisdom. Thanks again so much for making these videos!

  • @taruchitgoyal3735
    @taruchitgoyal3735 ปีที่แล้ว +2

    This was super good. I have been struggling to understand LU decomposition and it seemed the concept must very complex. But with this tutorial, all the prejudice against the topic got crushed.
    Thank you for the session.

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว

      Glad you enjoyed it! :) If it helps you, you can also watch my video about the PLU decomposition and download the PDF versions! :)

    • @taruchitgoyal3735
      @taruchitgoyal3735 ปีที่แล้ว

      @@brightsideofmaths Thank you.
      Can you also publish a tutorial on SVD-Singular Value Decomposition?

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว

      @@taruchitgoyal3735 Yes, this will be part of my linear algebra series: tbsom.de/s/la

  • @moon_dragon22
    @moon_dragon22 ปีที่แล้ว +2

    I am at the end of my master studies and re-learning things for math that I need to prove for my thesis. Your videos have given me hope that I can actually do it. Sincere thanks!!!

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว

      Thank you very much and thanks for the support :)

  • @drioko
    @drioko 7 หลายเดือนก่อน +1

    the colors you use help me feel more relaxed and pay attention. good choice on the yellow and warm colors

    • @brightsideofmaths
      @brightsideofmaths  7 หลายเดือนก่อน +1

      Thank you so much 😀
      Some people are annoyed by the bright colors such that I also offer dark version for all videos :)

  • @MalamIbnMalam
    @MalamIbnMalam 3 ปีที่แล้ว +7

    This is a FANTASTIC explanation! I must say it is quite a bit better than what I was taught by the University of Texas in Austin. Thank you for this video!

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      I'm just curious; who was your professor there?

    • @MalamIbnMalam
      @MalamIbnMalam 2 ปีที่แล้ว +1

      @@PunmasterSTP Dr.Robert van de Geijn

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      @@MalamIbnMalam I don't want to give too many details away, but I'll just say that I was affiliated with UT Austin at some point. I never ran into that person as far as I remember. Aside from that class, how have your studies been going?

  • @Virglsgames
    @Virglsgames 3 ปีที่แล้ว +6

    Wow! I am from Ukraine, so I practically did not understand anything from the words - I perceived it visually. However, I kind of got it! Thank you author!

    • @zunkitgetu8042
      @zunkitgetu8042 3 ปีที่แล้ว +2

      well u write a perfect English but u didn't understand his words?

    • @Virglsgames
      @Virglsgames 3 ปีที่แล้ว

      @@zunkitgetu8042Yes! Is it strange?

    • @vladimirsviridov3329
      @vladimirsviridov3329 3 ปีที่แล้ว

      @@Virglsgames yes! ahaha

  • @Dkdkxncnchz
    @Dkdkxncnchz 3 ปีที่แล้ว +4

    u literally saved my life thank you so much

  • @timotheesamazingchannel3721
    @timotheesamazingchannel3721 8 หลายเดือนก่อน

    This was so helpful thank you so much the first three minutes did more for me than the hour of lecture we spent on it

  • @kkkorobbb
    @kkkorobbb 7 หลายเดือนก่อน

    Thank you so much! Exam is tomorrow, and you just opened my eyes! It's amazing!

  • @vfrostbane225
    @vfrostbane225 ปีที่แล้ว +2

    This was super easy to understand and explained so simply! Thank you so much!

  • @desmondtayes1812
    @desmondtayes1812 7 หลายเดือนก่อน

    i finally found what i have been searching for amoung 10 videos. thanks

  • @esi5743
    @esi5743 5 หลายเดือนก่อน

    Great explanation! I very much appreciate your work.

    • @brightsideofmaths
      @brightsideofmaths  5 หลายเดือนก่อน

      Glad you enjoyed it! And thanks for the support!

  • @Mahfuj_Alam_Imon_
    @Mahfuj_Alam_Imon_ 10 หลายเดือนก่อน

    It was really fun watching this video; now the concepts of LU decomposition seem pretty easy to me.

    • @brightsideofmaths
      @brightsideofmaths  10 หลายเดือนก่อน +1

      Nice :) Also watch the PLU decomposition then :)

  • @justakizuner6359
    @justakizuner6359 2 ปีที่แล้ว +2

    This video is just what I need! Thank you professor!

  • @GandhiBoys
    @GandhiBoys 3 ปีที่แล้ว +5

    Not all heroes wear capes ✊
    Thank you!

  • @ああ-y9n8b
    @ああ-y9n8b 4 ปีที่แล้ว +2

    Thanks from Japan.

  • @ne0fuze620
    @ne0fuze620 2 ปีที่แล้ว +1

    Thank you very much! This explained a lot

  • @treckieeee5707
    @treckieeee5707 3 ปีที่แล้ว +3

    Thank you for this. ✨

  • @malikialgeriankabyleswag4200
    @malikialgeriankabyleswag4200 8 หลายเดือนก่อน

    Your workings are so efficient and elegantly presented. I love Germans lol

  • @biscuitsofdeath
    @biscuitsofdeath ปีที่แล้ว

    This is great. Way easier than creating separate matrices, but I see the value in knowing that you can multiply the inverse of elimination matrices to get a. Love the explanation, I found it easy to comprehend.

  • @LICHKING55Show
    @LICHKING55Show 3 ปีที่แล้ว +2

    Fantastic Tutorial!

  • @elfarouk3306
    @elfarouk3306 3 ปีที่แล้ว +2

    bro they should give you a nobel prize for that . thnx a lot

  • @vychuck
    @vychuck 3 ปีที่แล้ว +1

    Done it really clear and accessible way

  • @RobertMurphy-wm3ge
    @RobertMurphy-wm3ge 3 ปีที่แล้ว +1

    Excellent explanation. Thank you very much

  • @NikitinBest
    @NikitinBest 3 ปีที่แล้ว +1

    PI-Sharaga and Vseleon loves you

  • @agscholar21
    @agscholar21 ปีที่แล้ว

    Man I love it when I find a video that explains something better than my professor😂😂

  • @ammarabdelrazek5090
    @ammarabdelrazek5090 ปีที่แล้ว

    Thank you, really helpful
    I have seen many videos but they were just more confusing
    Thanks again

  • @sinecurve9999
    @sinecurve9999 4 ปีที่แล้ว +10

    I am embarrassed to admit my University linear algebra course never covered LU decomposition. Gaussian elimination, yes. Super weird!

    • @reiantaank3314
      @reiantaank3314 4 ปีที่แล้ว +2

      Same. I'm encountering it for the first time in my masters

    • @valawaters103
      @valawaters103 2 ปีที่แล้ว +2

      could it be because your professor didn't consider it important? I mean if you can do the gaussian elimination maybe you do not need the LU decomposition (or maybe you do, i do not know i am still an undergrand)

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      How have your studies been going?

    • @fruitygranulizer540
      @fruitygranulizer540 ปีที่แล้ว

      because it is only needed if u are doing computational linear algebra. otherwise, gaussian elimination is much more practical.

  • @deycitoloza7109
    @deycitoloza7109 3 ปีที่แล้ว +3

    ¡Genial! Me ayudó mucho esta explicacion.

  • @guesmimontadhar7363
    @guesmimontadhar7363 3 ปีที่แล้ว +2

    Great explaination! Thanks a lot!

  • @burakergocmen5661
    @burakergocmen5661 3 ปีที่แล้ว +1

    no need to another explanation. This is very good

  • @satyaprakashpandit1936
    @satyaprakashpandit1936 ปีที่แล้ว

    Concise , well explained, thank you.

  • @tekhal9779
    @tekhal9779 3 ปีที่แล้ว +1

    Thank you so much! It really helped me a lot

  • @dahoyasmine2248
    @dahoyasmine2248 3 ปีที่แล้ว +3

    Thank you so much, you have no idea how much this helped me !

  • @Hnaiuoscefuobney
    @Hnaiuoscefuobney 7 หลายเดือนก่อน

    Thank you very much from algeria 🇩🇿

  • @yozlemramadan4408
    @yozlemramadan4408 ปีที่แล้ว

    The only video which helped me to understand now this works! Thank you :))

  • @goki8166
    @goki8166 10 หลายเดือนก่อน

    u helped so a lot for my exam this video was so good the teacher showed the video to the whole class :D

    • @brightsideofmaths
      @brightsideofmaths  10 หลายเดือนก่อน +1

      Fantastic! You have a good teacher :)

  • @sivaramakrishnansubramania1956
    @sivaramakrishnansubramania1956 2 ปีที่แล้ว

    This is the quickest +complete primer to LU (and by extension LDU) decomposition

  • @pedro_alonso
    @pedro_alonso 4 ปีที่แล้ว +1

    Thanks from Brazil :D

  • @kundankrishna7467
    @kundankrishna7467 11 หลายเดือนก่อน

    Very good explanation.

    • @brightsideofmaths
      @brightsideofmaths  11 หลายเดือนก่อน

      Glad you liked it And thanks for your support :)

  • @cissy27200
    @cissy27200 3 ปีที่แล้ว +2

    Thank you omg !!

  • @anujnarode3315
    @anujnarode3315 3 ปีที่แล้ว +1

    helped me a lot. Thanks

  • @IMAHAPPYFATLARD
    @IMAHAPPYFATLARD 11 หลายเดือนก่อน +1

    Thanks!

  • @monsij2005
    @monsij2005 3 ปีที่แล้ว +1

    Awesome explanation !!

  • @sethproaps8899
    @sethproaps8899 6 วันที่ผ่านมา

    Thank you so much for this video. :)

  • @larslagauw5452
    @larslagauw5452 ปีที่แล้ว +1

    I failed my test because I didn't notice this is a tutorial for SQUARE MATRICES ONLY... Please put that in the title!

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว +1

      It's literally in the title written in the video at 0:14. Moreover, It's in the description and I also have a video about the PLU decomposition, which you can find in the pinned comments.

  • @عباسحسنعلي-قسمالكهرباء
    @عباسحسنعلي-قسمالكهرباء 10 หลายเดือนก่อน

    Thank you very very very much

    • @brightsideofmaths
      @brightsideofmaths  10 หลายเดือนก่อน

      You are very welcome and thank you for your support ;)

  • @rowansharaf8997
    @rowansharaf8997 2 ปีที่แล้ว

    Awesome explanation! God bless you!!

  • @miroabdalian2114
    @miroabdalian2114 3 ปีที่แล้ว +1

    well explained, thx

  • @hopelesssuprem1867
    @hopelesssuprem1867 ปีที่แล้ว

    Thank you so much for a such great explanation. This is the first video where I understood everything.

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว +1

      Great to hear!

    • @hopelesssuprem1867
      @hopelesssuprem1867 ปีที่แล้ว

      @@brightsideofmaths do you plan to create a guide about svd decomposition? This will be an excellent addition to another decompositions

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว +1

      @@hopelesssuprem1867 Yes, I will do this in the linear algebra course :)

    • @hopelesssuprem1867
      @hopelesssuprem1867 ปีที่แล้ว

      @@brightsideofmaths thank u so much. I will be waiting this a lot))

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว +1

      @@hopelesssuprem1867 At the moment, I have only a German video about this: th-cam.com/video/AS9dFYdykw0/w-d-xo.html

  • @오수진-r5f
    @오수진-r5f 2 ปีที่แล้ว

    You're amazing!!! Thanks a lot

  • @xooldude
    @xooldude ปีที่แล้ว

    Excellent teaching, pls make more of this content

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว +1

      Thank you, I will. I have a whole linear algebra course now that I will update in future! tbsom.de/s/la

    • @xooldude
      @xooldude ปีที่แล้ว

      @@brightsideofmaths thank you!

  • @hakanozturk8367
    @hakanozturk8367 2 ปีที่แล้ว

    thank you.

  • @kidymark16
    @kidymark16 3 ปีที่แล้ว

    THANK YOU very much sir

  • @LocksVid
    @LocksVid ปีที่แล้ว +1

    thx bro

  • @shivanshiverma8025
    @shivanshiverma8025 4 ปีที่แล้ว +1

    Bro, you are a savior! My teacher confused me like hell!

    • @PunmasterSTP
      @PunmasterSTP 2 ปีที่แล้ว

      How have your studies been going?

  • @narcisopaeste8985
    @narcisopaeste8985 3 ปีที่แล้ว

    Wow. I am from India. This is very amazing
    I'm watching this for my girlfriend.

  • @أوسكارأجدعفيلم-ي5ج
    @أوسكارأجدعفيلم-ي5ج 2 ปีที่แล้ว

    انا و اخويا من مصر مزنوقين و بنحبك يا جينرال

  • @duongmai1514
    @duongmai1514 5 หลายเดือนก่อน

    Thank you!

  • @yirokafalokarl-marx2008
    @yirokafalokarl-marx2008 3 ปีที่แล้ว

    Thank you so much !

  • @zathrasyes1287
    @zathrasyes1287 2 ปีที่แล้ว +1

    Could you make a good video about the incomplete LU decomposition?

  • @ricegoing
    @ricegoing 4 ปีที่แล้ว +2

    You're great ! vielen Dank

  • @crazycrash1157
    @crazycrash1157 7 หลายเดือนก่อน

    Quick question if anyone knows it, why couldnt you put +2 or +4 in the L matrix because thats what happens when you multiply the negative in does it matter ? your teaching is so much more clear thanmy prof wish you were him doing good

    • @brightsideofmaths
      @brightsideofmaths  7 หลายเดือนก่อน

      You can do the matrix multiplication to check that you put the correct number into L!

  • @LeVraiment
    @LeVraiment 3 ปีที่แล้ว

    Thank you so much

  • @dhananjaykupekar6892
    @dhananjaykupekar6892 3 ปีที่แล้ว

    Concise and easy nice!!!

  • @goose6258
    @goose6258 3 ปีที่แล้ว +4

    The matrices im working with always decompose into working with numbers that have decimals. This makes it really tedious. Is there an easier way to simplify matrices into LU when you are working with decimals?

    • @brightsideofmaths
      @brightsideofmaths  3 ปีที่แล้ว +1

      Just post the example here :)

    • @mirelaratu3113
      @mirelaratu3113 3 ปีที่แล้ว

      @@brightsideofmaths Please let me put an example of a matrix with fractions. I would like to understand how to solve it with this method. Thank you so very much! I'll write the following rows (7, 3, 1), (5, 3, 2), (4, 2, 2).

  • @fresh7995
    @fresh7995 ปีที่แล้ว

    how have u made it soo easy to understand lectures made it look like hell

  • @TheBigBanggggg
    @TheBigBanggggg ปีที่แล้ว +1

    MATHEMATICS = LEARNING STUFF WITHOUT LEARNING WHAT TO DO WITH IT.

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว

      You can do so many things with it. This will never fit in one video :)

    • @TheBigBanggggg
      @TheBigBanggggg ปีที่แล้ว

      @@brightsideofmaths From you, the obvious reaction ;-)

  • @shou-yickho2845
    @shou-yickho2845 3 ปีที่แล้ว

    im linking your utube channel on th bottom of my bacholers degree xD

  • @plusyuan
    @plusyuan 7 หลายเดือนก่อน

    learning just like a baby

  • @mustafamohammed8758
    @mustafamohammed8758 2 ปีที่แล้ว

    Thanks, But can you look at the last ROW in the last step.
    You subtracted R(fourth) - 3R(Thired) from the ROW it will give us = 0, -3*, 0, -4 ...... The -3* make it wrong.(we should have 0)

  • @priyanshkumar17
    @priyanshkumar17 7 หลายเดือนก่อน

    thanks !

  • @arindamchak
    @arindamchak 4 ปีที่แล้ว +1

    What if I take X2 = X2 + 2(X1) and keep 2 in the identity matrix column instead of (-2)?

    • @haseebkhawaja1050
      @haseebkhawaja1050 3 ปีที่แล้ว +1

      No when we got the negative no. We dont add but subtract the negative no.

  • @reamabdulsalam524
    @reamabdulsalam524 ปีที่แล้ว

    Hi is there any specific order I have to follow to convert the entries into zero ? Should I start from colum 1 from the left to the right from top to bottom or it doesn’t matter ? What if in one step I can convert two entries to zero ? How to place the k value in this situation ? I have this matrix and I have stuck 1,-2,2, second row 3,4,2, third row 1,-2,3 ! I could not find the answer in any of the websites please do explain in full , thanks

    • @brightsideofmaths
      @brightsideofmaths  ปีที่แล้ว

      Please check my Linear Algebra series where I explain the Gaussian elimination in all detail: tbsom.de/s/la

  • @zhengyangsong
    @zhengyangsong 4 ปีที่แล้ว

    Many thanks!!!!!!

  • @allyourcode
    @allyourcode 3 ปีที่แล้ว +1

    But... Why does this work? You keep writing an equals sign at the beginning of each line. Why are those equals signs correct? I understand for the first one, because obviously, A = IA, but for the rest, I am confused...

    • @brightsideofmaths
      @brightsideofmaths  3 ปีที่แล้ว

      I would suggest that you just calculate the matrix multiplication on the right-hand side for each line :)

  • @bense_tony
    @bense_tony 3 ปีที่แล้ว

    Awesome man

  • @karmaakabane9727
    @karmaakabane9727 11 หลายเดือนก่อน

    HI! I'd like to ask something,
    If one row tends to become all 0 when I tried an operation, does that mean I have to change rows before starting LU decomposition?

    • @brightsideofmaths
      @brightsideofmaths  11 หลายเดือนก่อน

      No, you can also check my video about the PLU decomposition: tbsom.de/s/ov

  • @legofan2284
    @legofan2284 2 ปีที่แล้ว

    Lecture about this was terrible. Thanks to this video I finally see it's just Gauss.

  • @dreammyday5044
    @dreammyday5044 3 ปีที่แล้ว

    what if I just use eliminating the first column and second column also got Zero?

  • @ewesonlim2734
    @ewesonlim2734 4 ปีที่แล้ว +1

    May i know usually to get zero at row 2 first element, do we always refer to row 1 either by addition or subtraction? Or we can use row 3 or row 4 ?

    • @ewesonlim2734
      @ewesonlim2734 4 ปีที่แล้ว

      ExSiZuGeSe thank you so much, yes you have answered my question completely

  • @helloyou4233
    @helloyou4233 4 ปีที่แล้ว

    awesome video

  • @haifa6004
    @haifa6004 4 ปีที่แล้ว

    VERY GOOD

  • @farhanrafid8584
    @farhanrafid8584 4 ปีที่แล้ว

    Man, love you

  • @HEEJINJO-x6o
    @HEEJINJO-x6o 2 หลายเดือนก่อน

    The last part is not R4- 3R3, It should be R4-3R1

  • @ashley0238
    @ashley0238 11 หลายเดือนก่อน

    omg the accent is so cute!!!! may I please know which accent is this?

  • @sabbirahmed3034
    @sabbirahmed3034 3 ปีที่แล้ว +1

    Which software do you use to write and record videos?

  • @romeojr.madrona7737
    @romeojr.madrona7737 24 วันที่ผ่านมา

    Hello! What application are you using in here?

    • @brightsideofmaths
      @brightsideofmaths  24 วันที่ผ่านมา +1

      Thanks for asking. You find all the information with the first link in the description.

  • @shohom350
    @shohom350 2 ปีที่แล้ว

    What to do when we have to switch two rows with each other.Urgent pls explain

    • @brightsideofmaths
      @brightsideofmaths  2 ปีที่แล้ว

      See here th-cam.com/video/E3cCRcdFGmE/w-d-xo.html

  • @zma_0878
    @zma_0878 4 ปีที่แล้ว +1

    Geniusly

  • @ryanjackson0x
    @ryanjackson0x 2 ปีที่แล้ว

    Is it true that AEn=U, where En=L^-1?

  • @bufdud4
    @bufdud4 7 หลายเดือนก่อน

    7:20 is wrong. You can't use the multiple of -3. That would not eliminate the fourth row. How did anyone not see that?

    • @brightsideofmaths
      @brightsideofmaths  7 หลายเดือนก่อน +1

      A rule of thumb: if you are the only one (out many people) who finds a very obvious mistake in a video, then it's quite likely that you are wrong. :)

    • @bufdud4
      @bufdud4 7 หลายเดือนก่อน

      @@brightsideofmaths I saw my mistake. I thought the -9 looked like a -3, haha. Thanks for your easy explanation though!

    • @brightsideofmaths
      @brightsideofmaths  7 หลายเดือนก่อน

      Perfect! You are welcome :)@@bufdud4

  • @wisdomidheme4937
    @wisdomidheme4937 3 ปีที่แล้ว

    Is it just me or does any other person thinks the last value was supposed to be -3 not just 3 ???