One of the strengths of the SAS/IML language is its flexibility. Recently, a SAS programmer asked how to generalize a program in a previous article. The original program solved one optimization problem. The reader said that she wants to solve this type of problem 300 times, each time using a
A simple example of how you can combine SAS and open-source technologies to solve real business issues.
An important application of nonlinear optimization is finding parameters of a model that fit data. For some models, the parameters are constrained by the data. A canonical example is the maximum likelihood estimation of a so-called "threshold parameter" for the three-parameter lognormal distribution. For this distribution, the objective function is
Major European football (soccer) leagues came to an end after an intensive year. Manchester City claimed the Premier League title after a high-intensity title race against Liverpool. It is unbelievable that Liverpool would have won 25 out of the last 27 PL titles with 97 points. Luckily, the Reds
Learn how Bayesian optimization works through a simple demo.
Customer risk rating models play a crucial role in complying with the Know Your Customer (KYC) and Customer Due Diligence (CDD) requirements, which are designed to assess customer risk and prevent fraud. Today, the most common form of the Customer Risk Rating model is a score-based risk rating model. This
There is one equation every retail store, call center, traffic, airport or hospital manager should know by heart. No, it’s not E = mc². The one I had in mind is this: W = 1 / (μ – λ) It may not look like much, but it can mean the
Burger and fries, wine and cheese, peanut butter and jelly … some things just go better together. For organizations embarking on digital transformation, AI and IoT just go better together. These two distinct technologies; AI and IoT (or AIoT) are a natural fit. To take an analogy from the human
When solving optimization problems, it is harder to specify a constrained optimization than an unconstrained one. A constrained optimization requires that you specify multiple constraints. One little typo or a missing minus sign can result in an infeasible problem or a solution that is unrelated to the true problem. This
This article shows how to perform an optimization in SAS when the parameters are restricted by nonlinear constraints. In particular, it solves an optimization problem where the parameters are constrained to lie in the annular region between two circles. The end of the article shows the path of partial solutions
In the oil industry you can make or lose money based on how good your forecasts are, so I’ve pulled together six papers that discuss different ways in which you can leverage analytics to optimize your output and more accurately predict your production performance. Written by employees at oil and
Ballpark Chasers A cross-country trip is pretty much an all-American experience, and so is baseball. Traveling around the country to see all 30 Major League Baseball (MLB) stadiums is not a new idea; there's even a social network between so-called "Ballpark Chasers" where people communicate and share their journeys. Even
Data analysts often fit a probability distribution to data. When you have access to the data, a common technique is to use maximum likelihood estimation (MLE) to compute the parameters of a distribution that are "most likely" to have produced the observed data. However, how can you fit a distribution
When you run an optimization, it is often not clear how to provide the optimization algorithm with an initial guess for the parameters. A good guess converges quickly to the optimal solution whereas a bad guess might diverge or require many iterations to converge. Many people use a default value
SAS will be represented by more than 20 attendees at the INFORMS Annual Meeting at the George R. Brown Convention Center (GBCC) in Houston, Texas. Officially the conference runs from Sunday, Oct. 22 through Wednesday, Oct. 25, but our activities in Houston start even earlier. Technology Workshops on Saturday, October
Every fall, highways, backroads and neighborhood streets nationwide take on a noticeable yellow hue, as school buses carefully and methodically transport students back to school. In some areas, including Boston, this massive transportation exercise can present a number of challenges. Boston Public Schools (BPS) provided transportation for 25,000 students via
Did you know that you can get SAS to compute symbolic (analytical) derivatives of simple functions, including applying the product rule, quotient rule, and chain rule? SAS can form the symbolic derivatives of single-variable functions and partial derivatives of multivariable functions. Furthermore, the derivatives are output in a form that
For colleges and universities, awarding financial aid today requires sophisticated analysis. When higher education leaders ask, “How can we use financial aid to help meet our institutional goals?” they need to consider many scenarios to balance strategic enrollment goals, student need, and institutional finances in order to optimize yield and
Tomorrow is Independence Day, a federal holiday in the United States. Flags are displayed everywhere, especially in Washington, D.C., where I live. So let's have a little Fun with Flags! The current U.S. flag has 50 stars, one per state, with five rows of six stars interleaved with four rows
Most numerical optimization routines require that the user provides an initial guess for the solution. I have previously described a method for choosing an initial guess for an optimization, which works well for low-dimensional optimization problems. Recently a SAS programmer asked how to find an initial guess when there are
Maximum likelihood estimation (MLE) is a powerful statistical technique that uses optimization techniques to fit parametric models. The technique finds the parameters that are "most likely" to have produced the observed data. SAS provides many tools for nonlinear optimization, so often the hardest part of maximum likelihood is writing down
A frequently asked question on SAS discussion forums concerns randomly assigning units (often patients in a study) to various experimental groups so that each group has approximately the same number of units. This basic problem is easily solved in SAS by using PROC SURVEYSELECT or a DATA step program. A
At SAS Global Forum last week, I saw a poster that used SAS/IML to optimized a quadratic objective function that arises in financial portfolio management (Xia, Eberhardt, and Kastin, 2017). The authors used the Newton-Raphson optimizer (NLPNRA routine) in SAS/IML to optimize a hypothetical portfolio of assets. The Newton-Raphson algorithm
The 2017 edition of SAS Global Forum, the largest annual SAS user group meeting, will be held at the Swan and Dolphin Resort in Orlando, Florida on April 2-5. Among the many analytic talks at SAS Global Forum 2017, several focus on operations research topics like optimization and simulation. If
Improving citizen happiness is an important goal for many, if not all, governments. But what is happiness really? Can it be objectively measured? Can we discover the key factors that best correlate with happiness? And ultimately, can governments implement policies and programs that maximize happiness? Is maximum happiness nothing more than
This article shows how to solve mixed integer linear programming (MILP) problems in SAS. In a mixed integer problem, some of the variables in the problem are integer-valued whereas others are continuous. The objective function is a linear function of the variables and the variables can be subject to linear
In some applications, you need to optimize a linear objective function of many variables, subject to linear constraints. Solving this problem is called linear programming or linear optimization. This article shows two ways to solve linear programming problems in SAS: You can use the OPTMODEL procedure in SAS/OR software or
The 2016 INFORMS Annual Meeting will be held at the Music City Center and Omni Nashville Hotel in downtown Nashville, TN on November 13-16, with pre-conference events starting on Saturday, November 12. SAS will be a major participant in this conference. Over two dozen people from SAS will attend, with
When shopping for a new TV, with many sets next to each other across a store wall, it is easy to compare the picture quality and brightness. What is not immediately evident and expected is the difference between how the set looked in the store and how it looks in your
Analytics Experience 2016 will be held on Sept. 12-14, 2016 at the Bellagio in Las Vegas, NV. There will be a great number of excellent talks and demonstrations at the conference, covering many aspects of SAS analytics and many practical applications. Several of these sessions deal directly with the use
