Solving Optimization Problems with MATLAB | Master Class with Loren Shure

MATLAB
19 Nov 202090:40
EducationalLearning
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TLDRIn this masterclass, Lauren Shore from MathWorks explores optimization techniques using MATLAB, covering a range of problems from linear to non-linear and mixed integer. She introduces the concept of optimization in everyday life and various fields, demonstrating how MATLAB can be utilized to find optimal solutions efficiently. The webinar delves into traditional and global optimization methods, including solver-based and problem-based approaches, automatic differentiation, and parallel computing. Participants learn how to apply these techniques to real-world challenges, such as the traveling salesman problem, and gain insights into the latest features of MATLAB's Optimization Toolbox.

Takeaways
  • ๐Ÿ“š Lauren Shore, a MathWorks veteran, conducted a masterclass webinar on optimization techniques using MATLAB, emphasizing practical applications and strategies.
  • ๐Ÿ” Optimization problems are ubiquitous, ranging from finance to engineering, often requiring the most efficient or least resource-intensive solutions.
  • ๐Ÿ› ๏ธ MATLAB's Optimization Toolbox and Global Optimization Toolbox offer a suite of solvers for addressing both traditional and global optimization challenges.
  • ๐Ÿ“ˆ The webinar covered two main approaches to optimization in MATLAB: solver-based and problem-based solvers, each with its advantages and applications.
  • ๐Ÿ“‰ Live scripts in MATLAB provide an interactive environment for coding, plotting, and documenting, which is useful for presenting technical information.
  • โš™๏ธ Automatic differentiation, introduced in the latest MATLAB release, computes gradients accurately without estimation, improving the efficiency of optimization.
  • ๐Ÿ“ The importance of verifying solutions and understanding the problem through visualization and iterative testing was highlighted in the context of optimization.
  • ๐Ÿงฌ Genetic algorithms and other global optimization techniques, such as particle swarm and surrogate optimization, were discussed for solving non-convex and non-smooth problems.
  • ๐Ÿ”ข Mixed integer programming problems, where some variables must be integers, were addressed, with examples like the traveling salesperson problem demonstrating real-world applications.
  • ๐Ÿ”„ The use of parallel computing to expedite optimization processes was presented, showcasing how multiple cores or a cluster can be utilized to enhance performance.
  • ๐ŸŒ MATLAB's community resources, including the MATLAB Expo and training courses, were recommended for further learning and problem-solving support.
Q & A
  • What is the main focus of the masterclass presented by Lauren Shore?

    -The masterclass focuses on optimization techniques using MATLAB, covering various methods to solve optimization problems that are prevalent in finance, business, engineering, and everyday life.

  • How does Lauren Shore introduce the concept of optimization in everyday life scenarios?

    -Lauren Shore uses the example of choosing the fastest or driest route to the bank, depending on the weather conditions, to illustrate how optimization decisions are made in everyday life, even if not formally recognized as such.

  • What is the purpose of using optimization techniques in problem-solving according to the masterclass?

    -Optimization techniques are used to find better or optimal designs, make better decisions, automate routine decisions, perform sensitivity or trade-off analysis, and potentially discover non-intuitive designs that can be more efficient or effective.

  • How does the masterclass differentiate between solver-based and problem-based approaches in MATLAB for optimization?

    -The solver-based approach uses MATLAB numeric arrays, matrices, vectors, and functions to set up and solve optimization problems, while the problem-based approach uses optimization variables and constraints within a structured problem framework to find solutions.

  • What is an example of a non-intuitive design discovered through optimization techniques mentioned in the masterclass?

    -An example given is a NASA-deployed antenna designed using a genetic algorithm. The resulting design, with its bends and twists, met the weight and volume requirements for the space shuttle and the performance specifications for the antenna, and it was unlike any design previously conceived by engineers.

  • What is the significance of the 'ml divide' operation in the context of least squares problems in MATLAB?

    -The 'ml divide' operation, also known as the backslash operator, is used to solve least squares problems efficiently. It is recommended as the best way to solve such problems in MATLAB due to its simplicity and effectiveness.

  • How does the masterclass demonstrate the process of solving a non-linear optimization problem in MATLAB?

    -The masterclass demonstrates by creating an anonymous function for the non-linear objective, plotting the function to visualize the surface, and then setting up an optimization problem with constraints and an initial starting point to find the minimum value using MATLAB's optimization tools.

  • What is the role of automatic differentiation in the optimization toolbox of MATLAB as discussed in the masterclass?

    -Automatic differentiation in MATLAB's optimization toolbox allows for the accurate computation of gradients at any point in the optimization process. This feature eliminates the need for estimating gradients manually, which can be less accurate and more time-consuming.

  • Can you explain the concept of mixed integer programming and its application as presented in the masterclass?

    -Mixed integer programming is a type of optimization problem where some of the variables are constrained to be integers. This is useful in scenarios where decisions need to be made in whole numbers, such as purchasing a set number of items or making binary decisions. The masterclass applies this concept to the traveling salesman problem, where the goal is to find the shortest path visiting a series of points with the constraint that certain variables represent theๆ•ดๆ•ฐ number of times a path is taken.

  • What are the advantages of using MATLAB's Live Editor for technical presentations and problem-solving as highlighted in the masterclass?

    -The Live Editor in MATLAB allows for the integration of narrative, code, and results in a single document, making it easier to present and share the problem-solving process. It also supports interactive graphs and the ability to directly manipulate and update the code within the document, enhancing the exploration and explanation of technical concepts.

Outlines
00:00
๐ŸŽ“ Introduction to Optimization Techniques

Lauren Shore welcomes attendees to the masterclass on optimization techniques using MATLAB, noting it is the final webinar in a series. She introduces herself and mentions her extensive experience with MathWorks. Lauren highlights the importance of optimization in various fields and provides everyday examples. She explains the design process for optimization and discusses the challenge of optimizing systems with numerous variables.

05:03
๐Ÿ“ˆ Gradient-Based Optimization Techniques

Lauren discusses gradient-based optimization techniques, emphasizing the importance of automatic techniques for efficiency. She explains how computers can systematically perform calculations and gradient estimates to find optimal solutions faster than manual methods. She touches on sensitivity and trade-off analysis and the possibility of finding non-intuitive designs, using NASA's antenna design as an example.

10:04
๐Ÿ”ข Solver-Based Optimization in MATLAB

Lauren introduces the solver-based approach for optimization in MATLAB, applicable to all optimization solvers in the Optimization Toolbox and Global Optimization Toolbox. She explains the process of specifying objective functions, constraints, and bounds, and how MATLAB returns function values and solution locations. Lauren uses a simple data fitting problem to demonstrate setting up and solving a system of linear equations in MATLAB.

15:05
๐Ÿ’ป Problem-Based Optimization in MATLAB

Lauren transitions to the problem-based approach for optimization, initially available for Optimization Toolbox solvers and later for global optimization techniques. She explains the use of optimization variables and constraints and demonstrates solving an example problem using the problem-based approach. Lauren compares solutions from the solver-based and problem-based methods, highlighting the advantages of each.

20:10
๐Ÿ“Š Data Fitting and Linear Constraints

Lauren delves into data fitting with linear constraints, emphasizing the importance of accurately fitting data points. She shows how to add constraints to ensure certain points fit precisely through the curve. Lauren compares solutions obtained with and without constraints and demonstrates using the problem-based approach to incorporate constraints and achieve optimal solutions.

25:12
๐Ÿ“‰ Non-Linear Optimization in MATLAB

Lauren discusses non-linear optimization, noting its prevalence in real-world problems. She presents a non-linear function and explains the use of anonymous functions in MATLAB. Lauren demonstrates setting up and solving a non-linear optimization problem using the problem-based approach, highlighting the importance of accurate gradient calculations through automatic differentiation.

30:13
๐Ÿ” Exploring Non-Linear Optimization Solutions

Lauren continues with non-linear optimization, showcasing MATLAB's automatic differentiation feature for accurate gradient evaluations. She compares solutions obtained using automatic differentiation and finite differences, illustrating the efficiency and accuracy of automatic differentiation. Lauren also touches on optimization tasks in the live editor and their advantages.

35:14
๐ŸŒ Mixed Integer Programming

Lauren introduces mixed integer programming, a technique useful for problems requiring some variables to be integers. She explains the traveling salesperson problem as an example and demonstrates setting up and solving the problem using MATLAB. Lauren discusses constraints and iterative methods to eliminate subtours, ensuring an optimal global solution.

40:16
๐ŸŒ Global Optimization Techniques

Lauren transitions to global optimization, explaining its goal of finding the lowest or highest value of a non-linear function with multiple local minima. She outlines various global optimization solvers, including multi-start, global search, pattern search, genetic algorithms, surrogate optimization, particle swarm, and simulated annealing. Lauren provides a high-level overview of each method and their applications.

45:22
๐Ÿ”„ Multi-Start and Global Search

Lauren details multi-start and global search techniques, which involve running local solvers from multiple start points to find global minima. She explains how multi-start evenly distributes starting points, while global search filters non-promising points. Lauren demonstrates solving an example problem with multi-start and global search, highlighting their effectiveness in finding optimal solutions.

50:32
๐Ÿ“ Pattern Search Optimization

Lauren explains pattern search, a derivative-free optimization method that evaluates function points around existing points and adjusts search patterns based on success. She demonstrates how pattern search expands and contracts the search grid to focus on optimal areas. Lauren shows the method's effectiveness in sampling the search space and finding global solutions.

55:35
๐Ÿงฌ Genetic Algorithms

Lauren introduces genetic algorithms, which use concepts from evolutionary biology to create and optimize generations of candidate solutions. She explains selection, crossover, and mutation processes in detail and demonstrates solving an optimization problem with a genetic algorithm. Lauren emphasizes the method's ability to work with both smooth and non-smooth functions.

00:41
๐Ÿ”ฌ Surrogate Optimization

Lauren discusses surrogate optimization, a method suitable for expensive function evaluations. She explains how surrogate functions approximate the actual function locally, allowing for efficient optimization. Lauren demonstrates solving an optimization problem with surrogate optimization, highlighting its ability to explore and refine solutions adaptively.

05:43
๐ŸŸ Particle Swarm Optimization

Lauren introduces particle swarm optimization, which simulates the behavior of flocks of birds or schools of fish. She explains how particles influence each other's velocities and positions to find optimal solutions. Lauren demonstrates the method, showing how particles explore the search space and converge on the global minimum.

10:45
๐Ÿงฉ Overview of Global Optimization Solvers

Lauren provides an overview of various global optimization solvers, comparing their suitability for different types of problems. She summarizes the key features of each method, including gradient-based solvers, derivative-free solvers, and specialized solvers for multi-objective optimization. Lauren emphasizes the importance of choosing the right solver for the problem at hand.

15:50
โš™๏ธ Speeding Up Optimization with Parallel Computing

Lauren discusses the benefits of parallel computing for speeding up optimization problems. She explains how parallel computing can evaluate multiple points simultaneously, improving efficiency. Lauren highlights the use of MATLAB's parallel computing tools and the potential for scaling up to larger clusters or cloud-based solutions.

20:58
๐Ÿ“ฅ Deploying Optimization Algorithms

Lauren covers the deployment of optimization algorithms using MATLAB Coder for generating C and C++ code. She explains how this allows optimization solutions to be applied to various hardware platforms. Lauren encourages users to provide feedback and suggestions for expanding MATLAB's capabilities in this area.

26:00
๐ŸŽ“ Conclusion and Resources

Lauren concludes the masterclass by summarizing key takeaways, including the variety of optimization problems that can be solved with MATLAB, the use of global optimization techniques, and the advantages of parallel computing and code generation. She provides resources for further learning and encourages participants to ask final questions. Lauren thanks the attendees and highlights upcoming events and challenges.

Mindmap
Keywords
๐Ÿ’กOptimization
Optimization refers to the process of finding the best solution to a problem, often in terms of maximizing or minimizing a particular objective. In the context of the video, optimization is the central theme, with a focus on using MATLAB to solve a variety of optimization problems across different domains such as finance, business, and engineering. The script discusses several techniques for optimization, including gradient-based methods and global optimization approaches.
๐Ÿ’กMATLAB
MATLAB is a programming environment and language widely used for numerical computing, visualization, and programming. Throughout the script, MATLAB is highlighted as the primary tool for demonstrating and solving optimization problems. The speaker shares knowledge on how to use various MATLAB functions and toolboxes to tackle different types of optimization challenges.
๐Ÿ’กDesign Variables
Design variables are parameters that can be adjusted to achieve an optimal solution in an optimization problem. The script uses the example of an engine's efficiency to illustrate how design variables, such as revolutions per minute and pressure ratio, can be manipulated to find the most efficient settings.
๐Ÿ’กGradient-Based Optimization
Gradient-based optimization is a method that uses the gradient, or the derivative, of a function to determine the direction of steepest ascent or descent. In the script, this concept is introduced as a way to find the optimal solution by iteratively moving in the direction that most improves the objective function, which is crucial for problems with a large number of design variables.
๐Ÿ’กGlobal Optimization
Global optimization is the process of finding the absolute best solution across an entire search space, as opposed to local optimization, which only guarantees finding the best solution in the immediate vicinity. The script discusses global optimization techniques such as multi-start, pattern search, and genetic algorithms, which are used to overcome the limitations of local optimization methods and find the global minimum or maximum of a function.
๐Ÿ’กHeuristic Methods
Heuristic methods are problem-solving techniques that use practical, rather than optimal, strategies to find a solution. In the context of the video, heuristic methods like genetic algorithms and particle swarm optimization are mentioned as effective approaches for solving complex optimization problems where traditional methods may not be suitable.
๐Ÿ’กSensitivity Analysis
Sensitivity analysis is the study of how the variation of input parameters affects the variation of the output of a model or a function. In the script, it is mentioned as a way to understand the impact of changing one variable on the overall efficiency, which can be particularly useful for making decisions and trade-offs in optimization problems.
๐Ÿ’กLive Script
A Live Script in MATLAB is an interactive document that allows users to run code, display output, and include narrative text all in one place. The script mentions Live Script as the format used for the demonstrations, highlighting its usefulness for combining code, results, and explanations in an interactive and shareable format.
๐Ÿ’กSymbolic Math Toolbox
The Symbolic Math Toolbox in MATLAB is a collection of functions that allows users to perform symbolic computation, such as creating symbolic variables, computing derivatives, and solving equations symbolically. The script discusses how this toolbox can be harnessed to compute gradients and Hessians for optimization problems, especially when dealing with high-dimensional spaces.
๐Ÿ’กMixed Integer Programming
Mixed Integer Programming (MIP) is a type of optimization problem where some of the variables are restricted to be integers. The script touches on this concept in the context of the traveling salesman problem, where certain decisions, like the number of cars or binary decisions, must be made in whole numbers, not fractions.
๐Ÿ’กParallel Computing
Parallel computing is a method in which a single computation is divided into multiple smaller tasks that can be executed simultaneously, reducing the overall computation time. The script mentions that optimization problems in MATLAB can take advantage of parallel computing to speed up the process, especially when dealing with large-scale or complex optimization tasks.
Highlights

Introduction to optimization techniques using MATLAB by Lauren Shore, a 30-year veteran at MathWorks.

Optimization problems are ubiquitous in finance, business, engineering, and everyday life.

Design process for optimization involves iterative adjustments of variables to meet objectives.

Illustration of manual optimization challenges using engine efficiency contours.

Advantages of using automatic optimization techniques for finding better or optimal designs.

Different modeling approaches for optimization: solver-based and problem-based solvers.

Demonstration of solving a simple linear system of equations using MATLAB.

Transformation of a least squares problem into an optimization problem.

Use of mldivide (backslash operator) for solving least squares problems in MATLAB.

Introduction to non-linear optimization and handling complex real-world problems.

Automatic differentiation in the Optimization Toolbox for accurate gradient computation.

Mixed Integer Programming for problems involving both continuous and integer variables.

Traveling Salesperson Problem (TSP) and its solution using mixed integer linear programming.

Global optimization strategies to find the absolute minimum in non-convex problems.

Overview of global optimization solvers: multi-start, global search, pattern search, genetic algorithms, surrogate optimization, particle swarm, and simulated annealing.

Multi-start strategy for optimization demonstrated with pharmacokinetic data.

Global search algorithm explained and demonstrated using MATLAB's peaks function.

Pattern search method using a pattern of search directions for optimization.

Genetic algorithms inspired by evolutionary biology for optimization problems.

Surrogate optimization for handling expensive function evaluations.

Particle swarm optimization mimicking the behavior of a flock of birds or a school of fish.

Strategies for speeding up optimization with parallel computing and MATLAB Parallel Server.

Automatic differentiation in the Optimization Toolbox for improved performance.

Conclusion summarizing the ability to solve a wide variety of optimization problems in MATLAB.

Transcripts
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