LU decomposition - An Example Calculation

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  • Опубликовано: 10 фев 2025

Комментарии • 282

  • @brightsideofmaths
    @brightsideofmaths  4 года назад +13

    Download the pdf version: tbsom.de/s/ov
    Watch my whole linear algebra course to learn the details: tbsom.de/s/la
    If you have a non-square matrix and need row exchanges, watch here: ruclips.net/video/E3cCRcdFGmE/видео.html

  • @IMAHAPPYFATLARD
    @IMAHAPPYFATLARD Год назад +2

    Thanks!

  • @notgeo3912
    @notgeo3912 3 года назад +48

    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!

  • @MisterAdri85
    @MisterAdri85 3 года назад +119

    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 года назад +28

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

    • @MisterAdri85
      @MisterAdri85 3 года назад +16

      @@brightsideofmaths haha sure will !

    • @PunmasterSTP
      @PunmasterSTP 3 года назад

      How did your exam end up going?

    • @MisterAdri85
      @MisterAdri85 3 года назад +5

      @@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 3 года назад

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

  • @jamespapakyriakopoulos6187
    @jamespapakyriakopoulos6187 4 года назад +41

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

    • @PunmasterSTP
      @PunmasterSTP 3 года назад

      How have your studies been going?

  • @hardy4331
    @hardy4331 4 года назад +329

    I should be giving my university fees to this guy.

    • @MalamIbnMalam
      @MalamIbnMalam 3 года назад +21

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

    • @eeshaanmj8656
      @eeshaanmj8656 2 года назад

      Then give

    • @Heisenberg8307
      @Heisenberg8307 2 года назад

      Contribute him in steady...

  • @drioko
    @drioko Год назад +2

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

    • @brightsideofmaths
      @brightsideofmaths  Год назад +1

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

  • @rascal609
    @rascal609 22 дня назад

    This was such a great walk through. I've read multiple descriptions online of LU decomposition, but this walk through, step by step, really helped me understand where both pieces were coming from! Thank you!

  • @agbandanalistowel4737
    @agbandanalistowel4737 3 года назад +5

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

  • @taruchitgoyal3735
    @taruchitgoyal3735 Год назад +4

    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  Год назад

      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 Год назад

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

    • @brightsideofmaths
      @brightsideofmaths  Год назад

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

  • @moon_dragon22
    @moon_dragon22 Год назад +3

    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!!!

  • @MalamIbnMalam
    @MalamIbnMalam 3 года назад +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 3 года назад

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

    • @MalamIbnMalam
      @MalamIbnMalam 3 года назад +1

      @@PunmasterSTP Dr.Robert van de Geijn

    • @PunmasterSTP
      @PunmasterSTP 3 года назад

      @@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?

  • @Dkdkxncnchz
    @Dkdkxncnchz 4 года назад +4

    u literally saved my life thank you so much

  • @kaif7312
    @kaif7312 4 года назад +42

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

    • @vychuck
      @vychuck 4 года назад +12

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

  • @Virglsgames
    @Virglsgames 4 года назад +7

    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 4 года назад +2

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

    • @Virglsgames
      @Virglsgames 4 года назад

      @@zunkitgetu8042Yes! Is it strange?

    • @vladimirsviridov3329
      @vladimirsviridov3329 3 года назад

      @@Virglsgames yes! ahaha

  • @PunmasterSTP
    @PunmasterSTP 3 года назад +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!

  • @timotheesamazingchannel3721
    @timotheesamazingchannel3721 Год назад

    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 11 месяцев назад

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

  • @vfrostbane225
    @vfrostbane225 2 года назад +2

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

  • @justakizuner6359
    @justakizuner6359 3 года назад +2

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

  • @esi5743
    @esi5743 9 месяцев назад +1

    Great explanation! I very much appreciate your work.

    • @brightsideofmaths
      @brightsideofmaths  9 месяцев назад

      Glad you enjoyed it! And thanks for the support!

  • @desmondtayes1812
    @desmondtayes1812 11 месяцев назад

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

  • @biscuitsofdeath
    @biscuitsofdeath Год назад

    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.

  • @Mahfuj_Alam_Imon_
    @Mahfuj_Alam_Imon_ Год назад

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

  • @ne0fuze620
    @ne0fuze620 2 года назад +1

    Thank you very much! This explained a lot

  • @ああ-y9n8b
    @ああ-y9n8b 4 года назад +2

    Thanks from Japan.

  • @vychuck
    @vychuck 4 года назад +1

    Done it really clear and accessible way

  • @RobertMurphy-wm3ge
    @RobertMurphy-wm3ge 3 года назад +1

    Excellent explanation. Thank you very much

  • @ammarabdelrazek5090
    @ammarabdelrazek5090 2 года назад

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

  • @LICHKING55Show
    @LICHKING55Show 4 года назад +2

    Fantastic Tutorial!

  • @goki8166
    @goki8166 Год назад

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

  • @yozlemramadan4408
    @yozlemramadan4408 Год назад

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

  • @chiponpon
    @chiponpon 3 месяца назад

    All the suffering was for naught… thanks for the enlightenment!!!

  • @deycitoloza7109
    @deycitoloza7109 4 года назад +3

    ¡Genial! Me ayudó mucho esta explicacion.

  • @treckieeee5707
    @treckieeee5707 4 года назад +3

    Thank you for this. ✨

  • @dahoyasmine2248
    @dahoyasmine2248 4 года назад +3

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

  • @guesmimontadhar7363
    @guesmimontadhar7363 4 года назад +2

    Great explaination! Thanks a lot!

  • @rosemariemira1499
    @rosemariemira1499 4 года назад +1

    Thank you so much! It really helped me a lot

  • @Sajad-d1q
    @Sajad-d1q 2 месяца назад

    There's much more to the story than is shown here. In fact, it's in no way so "obvious" why values can be continously written onto the L matrix without something going wrong, since matrix multiplication mixes things normally. Not surprisingly, that was the hardest part for me to finally figure out.

    • @brightsideofmaths
      @brightsideofmaths  2 месяца назад +1

      I have a whole video about row operations, see description. Using these, it's really easy to see why it works.

  • @SalmanShah-w1x
    @SalmanShah-w1x 4 месяца назад

    It's amazing, and easy to understand Thanks!😍

  • @00MercX
    @00MercX 2 месяца назад

    thank you so much you're an amazing teacher

  • @GandhiBoys
    @GandhiBoys 4 года назад +5

    Not all heroes wear capes ✊
    Thank you!

  • @satyaprakashpandit1936
    @satyaprakashpandit1936 Год назад

    Concise , well explained, thank you.

  • @pedro_alonso
    @pedro_alonso 4 года назад +1

    Thanks from Brazil :D

  • @hopelesssuprem1867
    @hopelesssuprem1867 2 года назад

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

    • @brightsideofmaths
      @brightsideofmaths  2 года назад +1

      Great to hear!

    • @hopelesssuprem1867
      @hopelesssuprem1867 2 года назад

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

    • @brightsideofmaths
      @brightsideofmaths  2 года назад +1

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

    • @hopelesssuprem1867
      @hopelesssuprem1867 2 года назад

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

    • @brightsideofmaths
      @brightsideofmaths  2 года назад +1

      @@hopelesssuprem1867 At the moment, I have only a German video about this: ruclips.net/video/AS9dFYdykw0/видео.html

  • @agscholar21
    @agscholar21 Год назад

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

  • @rowansharaf8997
    @rowansharaf8997 2 года назад

    Awesome explanation! God bless you!!

  • @TaoucheSoufiane
    @TaoucheSoufiane 11 месяцев назад

    Thank you very much from algeria 🇩🇿

  • @burakergocmen5661
    @burakergocmen5661 3 года назад +1

    no need to another explanation. This is very good

  • @LocksVid
    @LocksVid Год назад +1

    thx bro

  • @monsij2005
    @monsij2005 3 года назад +1

    Awesome explanation !!

  • @anujnarode3315
    @anujnarode3315 4 года назад +1

    helped me a lot. Thanks

  • @xooldude
    @xooldude 2 года назад

    Excellent teaching, pls make more of this content

    • @brightsideofmaths
      @brightsideofmaths  2 года назад +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 2 года назад

      @@brightsideofmaths thank you!

  • @elfarouk3306
    @elfarouk3306 3 года назад +2

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

  • @sinecurve9999
    @sinecurve9999 5 лет назад +11

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

    • @reiantaank3314
      @reiantaank3314 4 года назад +2

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

    • @valawaters103
      @valawaters103 3 года назад +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 3 года назад

      How have your studies been going?

    • @fruitygranulizer540
      @fruitygranulizer540 2 года назад

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

  • @sivaramakrishnansubramania1956
    @sivaramakrishnansubramania1956 2 года назад

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

  • @DuSmh
    @DuSmh 3 месяца назад

    u saved my life tysm

  • @kundankrishna7467
    @kundankrishna7467 Год назад

    Very good explanation.

  • @NikitinBest
    @NikitinBest 4 года назад +1

    PI-Sharaga and Vseleon loves you

  • @cissy27200
    @cissy27200 4 года назад +2

    Thank you omg !!

  • @오수진-r5f
    @오수진-r5f 2 года назад

    You're amazing!!! Thanks a lot

  • @malikialgeriankabyleswag4200
    @malikialgeriankabyleswag4200 Год назад

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

  • @brianmwila507
    @brianmwila507 2 месяца назад

    Well explained 🙏

  • @kidymark16
    @kidymark16 4 года назад

    THANK YOU very much sir

  • @sethproaps8899
    @sethproaps8899 4 месяца назад

    Thank you so much for this video. :)

  • @miroabdalian2114
    @miroabdalian2114 4 года назад +1

    well explained, thx

  • @أوسكارأجدعفيلم-ي5ج
    @أوسكارأجدعفيلم-ي5ج 3 года назад

    انا و اخويا من مصر مزنوقين و بنحبك يا جينرال

  • @narcisopaeste8985
    @narcisopaeste8985 3 года назад

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

  • @HungNguyen-ux4td
    @HungNguyen-ux4td Месяц назад

    8:15 Should it be -3(row3) to get 0 and -4 at forth row?

  • @khiemthongminh
    @khiemthongminh 4 года назад

    Thank you for the video.

  • @ricegoing
    @ricegoing 4 года назад +2

    You're great ! vielen Dank

  • @LeVraiment
    @LeVraiment 4 года назад

    Thank you so much

  • @عباسحسنعلي-قسمالكهرباء

    Thank you very very very much

  • @bewyb323
    @bewyb323 3 года назад

    thank you!

  • @hakanozturk8367
    @hakanozturk8367 3 года назад

    thank you.

  • @dhananjaykupekar6892
    @dhananjaykupekar6892 4 года назад

    Concise and easy nice!!!

  • @ananthakrishnank3208
    @ananthakrishnank3208 Год назад

    Thank you!

  • @Uygʻun-q2c
    @Uygʻun-q2c 3 месяца назад

    thanks

  • @larslagauw5452
    @larslagauw5452 2 года назад +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  2 года назад +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.

  • @zahariaspage9413
    @zahariaspage9413 27 дней назад

    You are a hero!!!

  • @shivanshiverma8025
    @shivanshiverma8025 4 года назад +1

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

    • @PunmasterSTP
      @PunmasterSTP 3 года назад

      How have your studies been going?

  • @aydnndurmaz
    @aydnndurmaz 26 дней назад

    Life saver!

  • @zeustheboerboel3794
    @zeustheboerboel3794 4 года назад

    I wish we had u in our university in India.

  • @ccbl6270
    @ccbl6270 5 лет назад +1

    thank you i get it

  • @zathrasyes1287
    @zathrasyes1287 3 года назад +1

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

  • @crazycrash1157
    @crazycrash1157 11 месяцев назад

    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  11 месяцев назад

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

  • @zhengyangsong
    @zhengyangsong 4 года назад

    Many thanks!!!!!!

  • @mustafamohammed8758
    @mustafamohammed8758 3 года назад

    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)

  • @ashley0238
    @ashley0238 Год назад

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

  • @robharding166
    @robharding166 Месяц назад

    I don't understand this, and I haven't heard of Gauss Elimination. I've always struggled to understand matrices and don't know where to start, I have a CFD1 resit exam with this type of linear algebra in 2 weeks. Any suggestions? Thanks!

    • @brightsideofmaths
      @brightsideofmaths  Месяц назад

      I have a whole Linear Algebra course on my website. See description :)

  • @TheBigBanggggg
    @TheBigBanggggg 2 года назад +1

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

    • @brightsideofmaths
      @brightsideofmaths  2 года назад

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

    • @TheBigBanggggg
      @TheBigBanggggg 2 года назад

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

  • @helloyou4233
    @helloyou4233 4 года назад

    awesome video

  • @bense_tony
    @bense_tony 4 года назад

    Awesome man

  • @haifa6004
    @haifa6004 4 года назад

    VERY GOOD

  • @beytulk
    @beytulk 3 года назад

    Thanks bıro!

  • @reamabdulsalam524
    @reamabdulsalam524 Год назад

    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  Год назад

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

  • @Bryanbro
    @Bryanbro 3 года назад

    Hello please I hope you see this in time I have my exam in a few hours. At 4:08, the -2 in green, can it also be a 2? That is how I would do it.

    • @brightsideofmaths
      @brightsideofmaths  3 года назад

      -(-2) = + 2
      Is that what you are asking?

    • @Bryanbro
      @Bryanbro 3 года назад

      @@brightsideofmaths yes! I would do +2 instead of - -2, would I get an incorrect LU composition this way?

    • @brightsideofmaths
      @brightsideofmaths  3 года назад

      @@Bryanbro In L, you still have to put in the number -2.

    • @Bryanbro
      @Bryanbro 3 года назад

      @@brightsideofmaths Yes, but it would be a +2 instead of the -2 that you put in. So would that be incorrect?

    • @brightsideofmaths
      @brightsideofmaths  3 года назад +1

      @@Bryanbro It still has to be the number -2. As I explained it in the video. The multiple you *subtract* is the one you put in L.

  • @devviz
    @devviz Год назад

    so the true purpose of lu decomposition is not necessarily to solve a matrix, but to demonstrate how gauss-jordan elimination method be performed?

    • @brightsideofmaths
      @brightsideofmaths  Год назад +1

      "Solve a matrix" is not a common term. The LU composition is used to solve a system of linear equations.

  • @goose6258
    @goose6258 4 года назад +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  4 года назад +1

      Just post the example here :)

    • @mirelaratu3113
      @mirelaratu3113 3 года назад

      @@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).

  • @karmagakunyaa
    @karmagakunyaa Год назад

    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  Год назад

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