Жыл бұрын
Пікірлер
@linaolausson4788 9 күн бұрын
Saved me a lot of frustration! Thank you!!
@TallysYunes 9 күн бұрын
You're welcome!
@mahbubhossain1852 15 күн бұрын
So cool idea of using Solver!!! I have solved a mathriddle by Solver too!!
@martimmoliveira 18 күн бұрын
THANKS!! Was struggling to open the .pkg but you helped a lot!
@adrian_730 21 күн бұрын
I've never commented on YT before but the moment I saw you divide blending problems into fixed and flexible I knew I struck gold and had to comment. I have been struggling for a whole day solving blending questions because I couldn't see the pattern and my textbook and lecture notes mention nothing useful. The way you explain them is so simple and beautiful. Thank you for turning my day around!
@TallysYunes 19 күн бұрын
Thank you so much for your kind words! I'm happy to hear the video was useful!
@sohomchat Ай бұрын
Thanks for the video. Can I use stochastic optimization to make a decision for a scenario that realized which I had not accounted for when I modeled the problem? In other words, is it only useful when I have complete knowledge on the finite number of possible scenarios?
@TallysYunes Ай бұрын
Correct. The stage-1 solution needs to be aware, a priori, of the possible scenarios of stage 2 and their respective probabilities. If there's a potential "other" scenario with a non-zero chance of taking place, you could include that too at the beginning and estimate some data for it.
@tireedaly2015 Ай бұрын
How does the solver know that the flow has to originate at nodes 1 and 2 and cannot arrive at 5 and 6 by coming directly come from 3 and 4?
@TallysYunes Ай бұрын
The flow constraints ensure that supply departs from the supplier notes (1 and 2) and that what happens at intermediate notes makes logical sense: whatever goes in has to go out. It also ensures that the demand nodes receive what they need.
@AjayKumarRamachandran Ай бұрын
Amazingly explained..thanks for the video
@TallysYunes Ай бұрын
Thanks! And you're welcome!
@bluetaurean Ай бұрын
Another wonderful video. Appreciate if you could recommend books to build a stronger understanding of the concepts.
@TallysYunes Ай бұрын
Thanks! Here's a book I like on these topics (at around a senior undergraduate/MBA level): "Spreadsheet Modeling and Decision Analysis" by Cliff Ragsdale.
@bluetaurean Ай бұрын
Fantastic videos and topics are well explained. Would love to see more videos with advanced topics on scheduling. You must publish a book or a paid course covering advanced topics.
@TallysYunes Ай бұрын
Thank you! I do have many video ideas for both basic and advanced topics. The hard part has been finding time to make them.
@markmusk521 Ай бұрын
you're good at simplifying this, thank you very much, I've learnt much for those two videos.
@TallysYunes Ай бұрын
Thank you for the feedback! If you still want more practice with sensitivity, I have a third video on this topic here in the channel as well.
@skkkylar Ай бұрын
very good!
@DJ-pn9te Ай бұрын
i think this is a good explanation and an overview for grasping the problems faced in the real world. And definitely Kudos to you Dr. I would add the time vector is important, is this for 1 day, 1 week, 1 month, etc. is this analysis run hourly as new demand and supply forecasts are introduced? Production may be on a schedule that differs from demand and Demand may increase or soften which are both pull/push on the system. Sometimes it is good to introduce dummy/slack supply and demand nodes that act as storage..........you touched on the warehouse phenomenon (that may have supply or demand characteristics) I think the main thing is to really think about the problem/map it in a diagram then when you have something, either write a LP program or if Excel can handle methodically go through an identify the obejctive function and segment the constraints... A+ classroom lecture to real world problems.... VALEU!
@TallysYunes Ай бұрын
You're correct. The problem in the video is, like every model, a simplification of the real-life situation. As you explain, there are many other factors that need to be taken into account. For the sake of a student learning these things for the first time, we could start with the model presented here and, little by little, incorporate additional details and increase the complexity. Depending on the needs of the transportation company, the level of complexity can reach a point where optimization can't handle it anymore and we need to resort to so-called heuristic approaches (a topic that I don't yet cover in my videos, but hope to get into at some point). I have a few friends who work as research scientists at Amazon and they tell me that this is indeed the case.
@ladobot8157 Ай бұрын
Sir, you are a hidden gem in the KZbin.
@TallysYunes Ай бұрын
Haha! You are too kind! Thank you!
@sauravsharma9295 Ай бұрын
@TallysYunes - I want to optimize a supply chain across multiple demand scenarios (e.g., Base, High, Low demand), each with assigned probabilities. so as to minimize costs while ensuring demand fulfillment for all products, considering uncertainties in demand (stochasticity), can I use Two-Stage stochastic op?
@TallysYunes Ай бұрын
From the description you provided, it sounds like you can!
@sauravsharma9295 Ай бұрын
@@TallysYunes - but how do I compare between different stochastic scenarios?
@TallysYunes Ай бұрын
I'm not sure what you mean by "compare between different scenarios."
@oltorftheviking 2 ай бұрын
Professor Yunes! I still after 15 years use the skills taught in your MBA class from UM. This is a great resource that's practical and easy to apply for real world problems. Thank you again!
@TallysYunes 2 ай бұрын
Oh my! This is so great to hear! Thank you!
@JackRyan101 2 ай бұрын
Really really helpful. I was totally confused by the way it was taught in class. Thank you.
@TallysYunes 2 ай бұрын
You're welcome! Glad to hear that the video helped!
@prateekmittal1483 2 ай бұрын
still my solver is displaying the same error i have number on right side or cell containing number and formulae on left side
@TallysYunes 2 ай бұрын
It's not clear to me what's happening in your case. What do you mean by "displaying the same error?" What error is it? Is there an error message?
@prateekmittal1483 2 ай бұрын
Yes it's like solver encountered an error in the objective cell
@TallysYunes 2 ай бұрын
That sounds like a different kind of problem. It's probably a typo in that particular formula (in the cell that is set to be the objective cell).
@prateekmittal1483 2 ай бұрын
But I have done everything correct and it's in my mates mac too. Only in mac but.....
@agagagag867 2 ай бұрын
That video is so detailed and helped me a lot! Thank you!!!
@TallysYunes 2 ай бұрын
You're welcome! Glad to hear it was helpful.
@Juan82777 2 ай бұрын
Brilliant !
@TallysYunes 2 ай бұрын
Thanks!
@SeanWyatt-h6f 2 ай бұрын
Thank you! I did not even know that I was trying to solve a flexible variable problem until I saw you define it. That is staying in my toolbox.
@TallysYunes 2 ай бұрын
Excellent!
@muniraakhmedova4551 2 ай бұрын
Phenomenally explained
@TallysYunes 2 ай бұрын
Thank you!
@mouleshmanikandan1392 3 ай бұрын
awesome sir :)
@mouleshmanikandan1392 3 ай бұрын
sir you are a life saver
@TallysYunes 3 ай бұрын
Glad to hear the video was helpful!
@lanchidaongoc 3 ай бұрын
Thanks a lot
@TallysYunes 3 ай бұрын
Happy to help!
@Sherlock_Ohms 5 ай бұрын
Hi Tallys, I was wondering if you could tell me why when you increase the initial amount to say, $100,000, the solver then says that the problem is no longer linear?
@TallysYunes 5 ай бұрын
Assuming it was solving before (with 50,000) as the initial amount and not complaining of non-linearity, simply changing the initial 50K to 100K should not be generating this issue. Therefore, it's some sort of bug. I've seen these before with Solver. Sometimes, clicking (or un-clicking) the box that says "Automatic scaling" in the Solver options takes care of this.
@Sherlock_Ohms 5 ай бұрын
@@TallysYunes Thanks! I suppose another way around it would be to convert the initial amount to thousands of dollars, so 100 in my case. This solves fine.
@TallysYunes 5 ай бұрын
Yes, indeed. Sometimes if you scale the numbers yourself so that the difference between the smallest and the largest number in the data is reduced, this kind of bug goes away. Good thinking!
@robertosei-danso5729 6 ай бұрын
How do you formulate this with two plants?
@TallysYunes 6 ай бұрын
If by "two plants" you mean two different products whose inventories have to be tracked, you can simply duplicate the variables and repeat the same set of constraints for each product individually.
@robertosei-danso5729 6 ай бұрын
@@TallysYunes It's more transshipment in my case. Solver cannot find a solution.
@TallysYunes 6 ай бұрын
Check out the transshipment example on my playlist (if you haven't yet) and double check that all your constraint formulas are correct. If it can't find a solution, there's at least one constraint that is being too strict.
@miho0628 6 ай бұрын
Anyone who got 6.333333 for X1 instead of 1.333333?
@TallysYunes 6 ай бұрын
This problem has alternative optimal solutions. As long as you still get 22.333 in cell H16 and all the constraints are satisfied, you're fine.
@miho0628 6 ай бұрын
@@TallysYunes thank you!
@xwz6957 7 ай бұрын
if my solver could not find a feasible solution, where and how can i find my own mistake?
@TallysYunes 7 ай бұрын
This is caused by the problem being over constrained and the issue is with one of the (or a group of the) constraints. What I usually do is this: go to the grey area (i.e. the variables), start with it empty, and then assign some simple values to the grey cells (for example 1 or 2) and check that the resulting calculations that use those cells are returning the values you'd expect to see. Or try inputting a solution that you know should be feasible and then see if some calculated number looks weird. For instance, in this problem, type in the gray area a solution that only makes one type of gasoline. Try this with all gasolines (one at a time). You'll eventually find out where the issue is. In the worst case, go back to the beginning of the video and double check that all the formulas you are typing match mine exactly. Good luck!
@roberthuff3122 7 ай бұрын
🎯 Key Takeaways for quick navigation: 00:00 *📚 Introduction to Integer Programming in Excel* - Overview of transitioning from linear to integer programming, focusing on integral or whole number variables and binary variables for decision-making. - Introduction to binary variables for yes/no decisions and their common applications. - Preview of utilizing binary and whole number variables in Excel models. 02:08 *🎯 Budget Allocation Problem: The Knapsack Problem* - Explanation of the budget allocation problem as a practical application of integer programming, referring to the historical knapsack problem. - Setting the scenario for applying a budget allocation strategy using binary variables in advertising channel selections. - Detailing the process of mapping out the problem's constraints and objectives using a hypothetical business case. 06:05 *💻 Setting up the Excel Model for Integer Programming* - Instructions on creating the Excel model for the problem, including data input, defining binary variables, and formulating the objective and constraints. - Demonstrating the setup of formulas for total exposure and total expense based on binary decisions. - Guidance on using Excel Solver for maximizing exposure within the budget constraint by adjusting Solver parameters for binary variables. 11:07 *🔄 Different Applications of the Knapsack Problem* - Describing the versatility of the knapsack problem by illustrating various real-life applications beyond budget allocation, such as camping gear selection and space mission preparation. - Highlighting the adaptability of the problem structure to different contexts, including time management, space utilization, and auditing projects. - Introduction to extending the binary variable model to accommodate logical conditions in subsequent scenarios. Made with HARPA AI
@vijayrao6321 7 ай бұрын
This is fantastic, Professor! I'd like your thoughts and advice on how to do an MCSim with triangular distribution where the lower bound is negative? Thanks in advance!
@TallysYunes 7 ай бұрын
What are the 3 parameters of this triangular distribution?
@vijayrao6321 7 ай бұрын
Essentially I’m trying to model future growth in an industrial company that has historically (15 years data) varied from -2% to +8% with median at 3%.
@TallysYunes 7 ай бұрын
If the triangular function doesn't allow you to enter a negative for the low end, you can shift everything up 2% points and subtract afterward. For example: Cell A = randtriangular(0, 0.05, 0.1), and B = A - 0.02. This will make cell B behave as if it were a randtriangular(-0.02, 0.03, 0.08).
@vijayrao6321 7 ай бұрын
@@TallysYunes Thanks, Prof! Will try this.🙏
@suryaramesh152 7 ай бұрын
So good ! Thank you so much
@TallysYunes 7 ай бұрын
You're welcome!
@JohnFerrante-ep3jw 7 ай бұрын
dude! I just enrolled in a mba and they have me doing linear optimization. The initial problems weren't bad, but it just seriously kicked up a notch. Would really appreciate if I could send you this one problem in particular and see how you would approach it.
@TallysYunes 7 ай бұрын
I can't do homework for you, but it's likely that the one you need to tackle is similar to one of the examples in my videos. Look through my Excel Models playlist.
@JohnFerrante-ep3jw 7 ай бұрын
@@TallysYunes of course not! I'll be sure to check out the videos. I'm struggling with determining if it's blending or allocation, and determining the inequalities for blending. Especially when there's multiple rates and units of measurement. Do you offer tutoring?
@TallysYunes 7 ай бұрын
At the moment I don't have time for one-on-one tutoring, but this is something your teacher would be able to clarify for you (it's their job). Have you tried reaching out to them? Do they offer office hours?
@Sherlock_Ohms 7 ай бұрын
Professor Yunes, Not sure if you still read these but I am loving these videos which help me in my job. My question is, could you force the variable cells to be integers?
@TallysYunes 7 ай бұрын
Thank you! I'm glad the videos are helping. Yes, you can add an "int" constraint on the gray cells. I don't do it in this video because I use this example to illustrate the ideas I go over at the end of the video to my students.
@Sherlock_Ohms 7 ай бұрын
@@TallysYunes Can I ask what book you recommend? I see a few popular recommendations online. What would you choose?
@TallysYunes 7 ай бұрын
Here's one that I like: www.amazon.com/Spreadsheet-Modeling-Decision-Analysis-Introduction/dp/130594741X
@mihaelazeger5705 7 ай бұрын
Hi sir, Can you tell me which video to watch to know how to model this problem in excel so I can solve it and follow through this video? Thanks in advance!
@TallysYunes 7 ай бұрын
I don't have a detailed video on that, but at the beginning of this video I show you the mathematical formulation and the setup of the Solver window (you can pause the video at that moment and look at what I did). The formulas in column F and in cell B12 are all the same: a SUMPRODUCT. If you watch and understand the Farmer Problem example I have on this channel, you should be able to do this one.
@KURASREEJA 8 ай бұрын
Good video, Thank you!
@matlholelosaba4977 8 ай бұрын
Recorded four years ago and still relevant and so helpful. I wonder how this will change with new developments in Excel and the use of AI.
@rg73140 8 ай бұрын
Hi I would like to check, if the constraint is this instead, what would the equation be? If we advertise on channel 3, we must also advertise on channel 9 and 10,
@TallysYunes 8 ай бұрын
In this case, you can deal with it as if it were two separate statements and it will result in two constraints: a) If we advertise on 3, we must also advertise on 9. b) if we advertise on 3, we must also advertise on 10. You can do each of the above with the "if this then that" formula that the video teaches.
@domfernandez98 8 ай бұрын
wasted hours yesterday checking whether my input variables were correct... Thank you so much for the help!
@TallysYunes 8 ай бұрын
You're welcome!
@zheng-p2h 9 ай бұрын
You are a very excellent teacher, thank you very much
@TallysYunes 9 ай бұрын
Thank you!
@koji.o 9 ай бұрын
Subscribed! I hope there's also a version using purely excel formulas, without using 3rd party paid programs such as 'Simvoi'
@TallysYunes 9 ай бұрын
Thank you! There may be, but I'm not aware of any native Monte Carlo facilities for Excel other than the brute force way that can become very time consuming.
@tbirdspy8911 9 ай бұрын
This was a huge help completing my homework assignment in time. Thank you!
@TallysYunes 9 ай бұрын
You're welcome!
@giggle_box16 10 ай бұрын
I undoubtably enjoyed your video. I subscribed right away.
@TallysYunes 10 ай бұрын
Awesome! Thank you!
@PalakpreetKaur-jb8mw 10 ай бұрын
🙌🏻🤌🏻
@Ahmedbahgat-u1s 10 ай бұрын
such a great man, you saved our life
@TallysYunes 10 ай бұрын
You're welcome.
@lydiekrickel6093 10 ай бұрын
Very well explained to be able to interpret these tables !
@TallysYunes 10 ай бұрын
Thank you! I'm happy to hear it helped!
@SardsSards-p7j 10 ай бұрын
Note that the you will get 74,908.9 as initial amount for target 100K if the inflows/outflows are baked in. Without inflows/outflows, you should get 71,179.44 as the initial amount needed.
@SardsSards-p7j 10 ай бұрын
Great Video, you deserve more subs. Keep it up!!
@SardsSards-p7j 10 ай бұрын
I meant great playlist, not just this video. Doing a marathon of the playlist now :)
@romeokodi9868 11 ай бұрын
You are great man thanks a lot
@TallysYunes 11 ай бұрын
Thank you! And you're welcome. I'm happy to hear the video was helpful.
@vusiarmstrongmalinga6676 11 ай бұрын
Thank you for the clear tutorial. Manage to understand this clearly now.
@TallysYunes 11 ай бұрын
Great to hear!
@swaritagarwal6387 11 ай бұрын
Amazing! Really helpful
@TallysYunes 11 ай бұрын
Thank you!