Big M Method - Simplex Algorithm
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- Опубліковано 4 жов 2024
- A quick guide to how to use the Big M Method for the Simplex algorithm which is used for problems involving "greater than or equals to" constraints, from the Decision Maths course. Whilst this is written with the Edexcel 2017 syllabus in mind, it is suitable for other courses. All other algorithms and procedures for the course will have their own videos too.
Original Simplex Algorithm video:
• The Simplex Algorithm
Playlist for Decision Maths Algorithms and Procedures: • Decision Maths Algorit...
Music: Look At Me Now (Acoustic) - Simon Bell, available from tribeofnoise.com.
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You did in 6 mins what took hours on the uni class lol. Thank you
You are most welcome, and I am glad that it was useful to you.
Absolutely class video - 6 minutes when other videos are 30+mins, but still teaches you everything. Thanks!
Thank you fo rthe kind words - you are very welcome. I am glad it was helpful to you.
I was searching this method for a while now and i finally found you. Really helpful and really clear explanation. Thank you!!
I'm glad it was helpful to you!
you just won a new subscriber from this video. THANK YOU!!!!!
You're welcome. I'm glad it was helpful to you.
You had the best explanation of artificial variables both on youtube and from my uni teachers. I finally understood them! Thank you. your voice is soft and patient making is easy to listen and understand what you were saying.
Ha ha. Too kind! I am glad that it was helpful to you. Please do feel free to send the video on to any of your fellow students who are struggling with it!
Big M? Must stand for “Big Mastery”…of the material, because you seem to understand it so well. Thanks for another illuminating video!
Wow ,so short time you clearly give a whole concept .thank u so much
Thanks a lot!!
Your example helped me on my university project
I am glad it was useful for you.
Very helpful and concise! Thanks a lot
This video is so useful. Thank you so much. Also loved the music at the end
The feasible region is open sided in this question. Can't P be infinite? I can see that the "solution" shown gives us one of the 2 vertices of the region, but that isn't maximising the function, it's only finding the better of those 2 points..... Can you throw any light on this please?
You raise a very good point, and I think that you are correct. I will give this some more thought, but your suggestion seems valid. I can only conclude that I have chosen a poor example for demonstrating the technique! Since the point of the video is to show how to use the Big M method, I would guess that it is not too much of an issue, but I may well have to remake this video... Thank you for raising this.
@@mathshelpwithmrorys8555 Definitely correct, if you draw the graph you get an open sided region bounded by Y axis, y=x-11 and x+3y=15. If we choose say (10,10) from the original, it fits the constraints, gives P=40.
Don't need to remake the video - it demonstrates the method well - hence me recommending it to my class :-)
What we did do (out of interest) was added in an extra constraint x+3y=30 (boring I know) which then gives a trapezium shaped closed region, then ran big M again - the passes take you to(0,5), then (12,1) and then to the max value of 36.25 at (15.75, 4.75). Extra iteration, but it all works. If you really wanted to remake, could add in this extra pass......
With interpretation (of the original), it looks to me that what you get with an open region is a solution which reduces the slack to zero, so is on the lines. Could we say that it's the best solution that is most efficient maybe.... no slack, no wasted resources. I'm guessing here, but it's at least making me think a bit. I was being lazy in asking you for interpretation really (sorry) in the hope there was some glaring thing I'd never considered/noticed, but it's always nice to think that you've come up with an interesting question.... :-)
@@nealhankinson5091 That sounds like a good way round it, and I'm just a little annoyed that I didn't spot it in the first case. However, I am glad to hear that it was useful to you and your class.
At the point where you look for the smallest positive value of theta and there is none - I think the right conclusion at that point is that the problem is unbounded. It should be an indication of this?
Hi! I was wondering if you had any plans to make any more videos on decision maths. We have finished the textbook in lesson now but revising it for the book is confusing and these videos make a lot more sense :) of course we don’t want to force you into making videos but I wanted to let you know that they really are useful👍 thanks:)
Hi. FIrstly, I am glad to hear that the videos are proving helpful to you. Yes, I am planning on having a few more videos. I have one on critical path analysis that I should be uploading either today or tomorrow, and I am in the middle of working on one on Gantt charts and resource levelling. After that, there should be one on scheduling. When those three are all on, that should be everything from the Edexcel Decision Maths course covered. If there is anything else that you think would be helpful to you, please feel free to suggest something! And don't worry, you're not forcing me to do them, I quite enjoy it and they are useful for my students too!
I don't know if you have subscribed and so would see it arrive, but the next video is now up: ua-cam.com/video/XqVdHW9-0DE/v-deo.html Enjoy!
Maths Help with Mr Orys yes I am subscribed:) thanks !
Thank you so much,
It was very useful .
You saved my life 😘
Ha ha. All in a day's work! I'm glad it was helpful.
Thank you!
You're welcome!
thanks
You didn't add S2 in Basic variables why?
Same question.
Thank you
Why did we not write s2 in basic variables?
legend
why do we have to add the objective function with an artificial variables with an arbitrarily large coefficient 'm' ?
Just saw your comment, don’t know if it still helps but: Say if you have x+y >= 10, and if you only have one variable x+y-s=10, there is a possibility that for eg x=0 and y=0, then 0+0-s ( a positive number) = 10, and that is not right. So we add a artificial variable to make x+y-s+a=10 stand for all possible values of x and y. And adding arbitrarily large number M, is just the algorithm, some mathematicians came up with this method that solves linear programming.
@@jiaweichen9892 i appreciate your comment . thanks
misinterpretation ,there is no maximum solution .problem is unbounded
exactly what i was thinking.
Wrong: the problem is unbounded. For example, try x=1000, y=1000.
god bless...
Thank you.