Operations Research 05A: Sensitivity Analysis & Shadow Price

[@YongWang]

Hi Guys, please comment and let me know what you think about this Operations Research Open Course. Your feedback is really appreciated. If you enjoy the video, please subscribe and share. All my replies here are only related to the content in my own videos. I am afraid I won't be able to answer other questions. Thanks for your understanding.

[@robertramos8676]

Very good, thanks!

[@eddymdi4953]

Can you share ppt? Thank you, well done Yong !

[@chickyjong]

im not enjoying this course not because of the subject but bcs of my lecturers...i really like operations thinggy but my lecturer makes it worse

[@tuongnguyen9391]

This is really good !! The visualization is excellent

[@Explorer982]

Very helpful ty

[@diaryofxandria]

Thank you so much for this. We have online classes and our professor can't discuss this topic and we have to self study to be able to understand the concepts behind this. I am very much grateful for this video, sir. It is very clear, precise and concise. It is very easy to follow and understand. More power!

[@فرحةالافندي]

شكرا جدا لحضرتك الحمد لله فهمت الجزء الخاص بالمدى Before I watched your explanation I couldn't know how we calculate the range but now I understand it from you All thanks from Egypt

[@Montecristo1994]

One of the best videos on this topic. To the point and very clear explanation, thank you sir.

[@brentgallagher3603]

Wow, I've watch every video by you thus far on OR and you are a scientist and an artist!

[@YongWang]

Thanks, Brent, for the comments

[@Zeynep999-o5e]

I never comment on study videos, but this was awesome and on point. Thanks!

[@keremkansu4756]

yong abi saol cok güzel anlatmışsın türkiyeden selamlar öptüm canım

[@YongWang]

You are welcome, Kerem.

[@sobiah11]

That was very useful to understand shadow prices, thank you :D

[@YongWang]

Thanks for the comment, Sobiah

[@CarloSyRocks]

noods?

[@kigandariham8984]

Love how u make it look easy to understand

[@efeerol2805]

I had difficulty understanding this topic, but the video helped a lot. Thank you.

[@negincheraghi4921]

Thank you clear explanation. I have a question. How we determine the profit range to change?how about slack and surplus?

[@shavindipathirana]

Thank you very much. All my problems regarding sensitivity analysis were solved :-)

[@YongWang]

glad to know it helped, Shavindi

[@omertahtali1824]

A very good video, thanks for your effort. I hope that it will help with my exam tomorrow

[@menzoclop1850]

Thank you so much for your explanations. It's much easier to understand the process now (I was lost in class)

[@md.abdullahalrafi6496]

Oh my god!! You made this topic so damn easy!!!!!!!!!!!!!! Thanks, man.

[@jhonjohon5914]

Thank you for this series. It is really impressive.

[@YongWang]

Thanks for the comment, jhon

[@andreabaltazar2596]

amazing video finally I understood shadow and optimal range thanks

[@premsanthanam572]

Amazing!!!! videos on operations research. You have a great skill of teaching complex subjects

[@suhailali4960]

Thank you so much for making such a video. You have taught very good!

[@AmanSingh-go1qm]

that was the best explanation, i could get on the subject sir

[@psybeam568]

i'll pass the class thanks to you

[@YongWang]

Thanks, ufuk

[@KayambuMadhavan]

Very nice explanation.Thanks for your effort.

[@YongWang]

No problem, Kayambu.

[@princebautista]

How did you get A and ZA on 2:10 ?

[@asutoshsubudhi2448]

crisp and crystal clear ...

[@YongWang]

Thanks, Asutosh

[@Alcyeragraeth]

I really appreciate your videos, sir.

[@peterleonard.k2265]

wow. thanks for the lecture on this topic. am nowb bright enough

[@YongWang]

Glad you liked it, Peter.

[@CHEMISTRY_4_EVERYONE]

Can u be a bit clear on the last point that y should -c1/c2 be within both the slope to maintain optimality.

[@gladydelacruz6839]

Thank you for this! But how would you know the sensitivity ranges for the profit without a given additional value for the max z? Should I just assume? Thank very much!

[@YongWang]

Yes, Glady. You can just assume.

[@AdrianColumbus]

@@YongWang Hi, thanks so much for this video! IT helped me in most part but there are still some uncertainties that I have. At 5:40, for the optimality range, its -1/2 =< -C1/C2 =< -2. May I ask how did you get the value of -1/2 and -2?

[@SequinBrain]

Do you have any videos for LP problems that have 3 or more variables? How do we find the slope for 3 variables?

[@prathameshmohite3008]

How will you calculate the shadow price if there are more than 2 variables and conduct sensitivity analysis on the objective function coefficients?

[@chowterry3603]

sir, if the number of the coefficient in the objective function is more than two, does the optimal range formula still work?

[@YongWang]

Great question. The optimal range formula does not work in that case. But the basic concept of sensitivity analysis still applies, i.e., how the changes in the rhs or coefficients affect the optimal solution.

[@huynhquangloc5590]

Thank you very much, you're my savior!!

[@srishtimaheshwari8708]

how did you find the slope and optimality range? please explain asap

[@camilaparola2781]

Thank you for sharing!!

[@YongWang]

happy to share

[@JingZhi45]

Hi, thanks so much for this video! IT helped me in most part but there are still some uncertainties that I have. At 5:40, for the optimality range, its -1/2 =< -C1/C2 =< -2. May I ask how did you get the value of -1/2 and -2? Sorry if this is a dumb question but I just started learning this, still haven't really gotten the hang of it yet.

[@JingZhi45]

alright its okay can ignore this, I think I've found out why haha. But still anw, thanks for the vid!

[@kavishdaya3594]

@@JingZhi45 please tell me how was the values determined im also new to this topic

[@bryanencalada9574]

@@kavishdaya3594 those are the slopes of the constraint equations. You can write each in y intercept form (where x2 would be your y value) and you obtain a slope of -1/2 for m2 and -2 for m1 so the objective value line has to lie within those 2 slope boundaries. Ik its a year later but hope this helps lol

[@quaternion4565]

Thanks for your videos, the lecture that my prof presents is too abstract and a nightmare to follow with too many proofs. This is much easier to digest with subtitle as well!

[@Salmamohameddd]

Thank you so much. Very great explanation

[@nathanmiller1779]

Fantastic explanation with corresponding graphics. Thanks for your great work!

[@mohamedmagdy6956]

Loved this explaining

[@YongWang]

Thanks, Mohamed.

[@ruthiekhersy7634]

very good explanation. it was very helpful. good job

[@julmarmisa695]

How did you get the slopes?

[@miikkafisher8565]

I wish I could like this video twice

[@asitpawan1212]

The best explanation! Thanks :)

[@YongWang]

You are welcome, Asit

[@abdul-muminfusheini859]

Thank you sir. You helped me a lot.

[@aquamanGR]

Hi! Great video - it would be excellent if you could also post the AMPL code to solve the problem.

[@waleed9083]

What is the shadow price in operation research?

[@caioillaabtibol6132]

Great video!

[@user-cq5lp3wq5z]

useful and easy to understand. thx!

[@pengziyan9180]

best video ever

[@humbatgasimov6452]

Wonderful Video.

[@Ampelman123]

Damn my professor did a 2h lecture on this leaving everyone fucking confused and here I find a seven minute video where everything is crystal clear...

[@d3yadav]

Very nice explanation

[@YongWang]

thanks, dharmender

[@AnkitVatscheakers]

Very nice and helpful video. But what if we increase the RHS values of both constraints on the same time?

[@YongWang]

Ankit, good question. In that case, you can still calculate the optimal value of the objective function and see how the changes in available resources (which is time in this example) can affect the optimal solution.

[@AnkitVatscheakers]

Yong Wang thanks for the reply. But we r already working on maximum capacity and increasing one more unit applies that we r exceeding it. In that case only one constraint can be changed. Is it right?

[@wreno7879]

Thank u sir, this really save my credits!

[@YongWang]

Glad it helped

[@marcmerih]

Thank you for this video!

[@YongWang]

You are welcome, Vivioux

[@Shavinderyt]

what would we do if we are given the value for c1 (100 for example) and not c2 for the optimal range?

[@foziakhan9791]

Then we can put value of c2 from 50 to 200 bcz by puting these values the optimum solution remains between two slopes

[@YongWang]

@@foziakhan9791 that's right

[@kritikakarthikeyan5832]

can you please tell me how you got :- -1/2>=-c1/c2>=-2 as the optimality range?

[@YashRoy]

-1/2 is the slope of the first constraint and -2 is the slope of the other constraint. you want your optimum solution to be between these two slopes as they give us the feasible solution area.

[@YongWang]

Thanks, Yash. You explanation is clear and correct. Thumbs up!

[@TheQueenEPK]

Thank you. It was helpful

[@ZenoDiac]

Good explanation, thanks

[@penjelajahmakna]

Thanks Sir. It is a very clear and helpful video :)

[@YongWang]

Thanks

[@BurziFreestyle]

super clear!!!

[@DikasLittleWorld]

it helps me a lot, thankyou!!!!

[@YongWang]

you are welcome, Dika

[@gokcenafsin5366]

you are a legend

[@YongWang]

Thanks, Gokcen. I wish.

[@augustogaliza]

Very nice! Thank you!

[@YongWang]

Glad you liked it, Augusto

[@osamahomair2020]

well done thanks for your work

[@RayRay-yt5pe]

Thank you! Very much

[@Mo7amedxd]

Thanks prof but I have a question when u get the slope 0.5≤c1/c2 ≤2 I didn't get it How did u get it while c1/c2 in this problem 300/200 And thanks again ♥️♥️

[@miazhang5866]

MANY THANKS, SIR!

[@YongWang]

Thanks, Mia

[@bluelobster6100]

you are the best

[@YongWang]

I am? Thanks.

[@shubhamsd100]

Thank you so much!!!

[@njabulomahlalela2912]

That was dope!

[@kubranuroksuz7715]

thanks for your effort. This video is really clear and helpful :))

[@YongWang]

Thanks

[@ahmedobidat1743]

Does anyone know how to get the ranges for the shadow prices? Thanks

[@YongWang]

Ahmed, The shadow I mentioned in the video is a value, not a range.

[@alidenby2830]

Thank you! Very Helpful

[@YongWang]

glad it helped

[@6193bood]

god bless you

[@YongWang]

thanks, Abdulla

[@cvismenu]

Thank you

[@Snowmanver2]

good explanation

[@shakeelansari8657]

Very nice.

[@YongWang]

Thanks, Shakeel.

[@gautampadiyar4558]

Beautiful!

[@NK-lg5ql]

thank you very much

[@YongWang]

You are welcome, N K

[@chandan5908]

Beautiful.

[@damiancsj5812]

amazing! thank you so much

[@joshuawang8300]

Thank you!!

[@mmabs__]

Heeeeeelp please T.T can you tell me where the 4000/3 from?

[@rohatrobinsarac4803]

I haven't done the calculations myself, but I am fairly certain that it is the value you get from plugging the optimal solution of x1 and x2 into the function max(z)=300x1+200x2

[@YongWang]

@@rohatrobinsarac4803 that's right. it's the optimal z value

[@fleecyfeathers5356]

Thank you very much Sir

[@YongWang]

Thanks

[@yihui7176]

thank u for this!

[@YongWang]

You are welcome, YH

[@jiteshtokas2229]

sir thank you much for this :)

[@Raison_d-etre]

Interesting approach, but it'd have been useful to see the graphical interpretation of the last problem.

[@aanlungyee9533]

thanks man! much appreciated

[@YongWang]

Thanks, Rainnie

[@foziakhan9791]

very very helpful vidio

[@YongWang]

glad you liked it, Fozia

[@mojahedalmalki5124]

thanks very very very very much

[@YongWang]

you are very very very very welcome, Mojahed

[@xalamukanibaloyi1500]

well explained

[@YongWang]

thanks for the comment, Xalamukani (trying to spell your name correctly)

[@samihakhan1717]

thank u sir.

[@YongWang]

no problem, Samiha

[@armandkana5083]

can you add a video about reduced price ?

[@YongWang]

basically, you just follow the same procedure for reduced price and resources

[@humbatgasimov6452]

Nice.

[@meldaercan7072]

Isn’t the modelling wrong. I mean why didn’t we eliminate numbers of products like number of product 1 produced at machine 1.

[@humbatgasimov6452]

Good.

[@MohamedAhmed-vy9ow]

perfeeeeeeeect

[@pablolerdodetejada1871]

You are a fucking leggend my man I jst learned everything i need for my final in a couple of hours

[@ruthnicolepamorada1355]

5:08