Analytics | Data Visualization | Programming Tips

Rick WicklinMarch 24, 2025 0

The quantile fit plot: Comparing empirical and predicted quantiles for a univariate model

A common task in statistics is to model data by using a parametric probability distribution, such as the normal, lognormal, beta, or gamma distributions. There are many ways to assess how well the model fits the data, including graphical methods such as a Q-Q plot and formal statistical tests such

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Learn SAS | Programming Tips

Rick WicklinMarch 17, 2025 0

Find the location of a run-time error in a user-defined function in SAS

Every programmer makes errors. Therefore, learning to debug a program is an important part of learning to program. Another skill is learning to decipher cryptic error messages, which can be as hard to interpret as hieroglyphs. One helpful skill is learning to navigate a "traceback" error. A traceback error message

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Data Management | Programming Tips

Stu SztukowskiMarch 14, 2025 0

How to create and manage Python Virtual Environments

Wouldn’t it be great if we could create a Python environment with only the packages and versions we need? Enter: virtual environments.

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Analytics | Programming Tips

Rick WicklinMarch 10, 2025 0

Pi to the power of pi

Happy Pi Day! Every year on March 14th (written 3/14 in the US), people in the mathematical sciences celebrate "all things pi-related" because 3.14 is the three-decimal approximation to π ≈ 3.14159265358979.... The purpose of this day is to have fun, celebrate the importance of mathematics, and maybe learn a

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Programming Tips

Sean FordMarch 7, 2025 0

Install VS Code extensions offline: step-by-step guide

This article provides a step-by-step guide on manually installing VS Code extensions when access to the online marketplace is restricted, including downloading .vsix files from GitHub and handling dependencies.

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Analytics | Learn SAS | Programming Tips

Rick WicklinMarch 3, 2025 0

An explicit formula for eigenvalues of an AR(1) correlation matrix

The first-order autoregressive (AR(1)) correlation structure is important for applications in time series modeling and for repeated measures analysis. The AR(1) model provides a simple situations where measurements (on the same subject) that are closer in time are correlated more strongly than measurements recorded far apart. The AR(1) model uses

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Programming Tips

Simon ToppFebruary 28, 2025 0

SAS Container Runtime Testbench: A field developed tool for SAS Intelligent Decisioning

SAS' Simon Topp walks you through how to setup SAS Container Runtime Testbench to make operating and debugging your SAS Intelligent Decisioning decisions a breeze

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English

Analytics | Learn SAS | Programming Tips

Rick WicklinFebruary 17, 2025 0

Deviance residuals and the DEVIANCE function in SAS

Many people have an intuitive feel for residuals in least square models and know that the sum of squared residuals is a goodness-of-fit measure. Generalized linear regression models use a different but related idea, called deviance residuals. What are deviance residuals, and how can you compute them? Deviance residuals (and

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Advanced Analytics | Analytics | Artificial Intelligence | Programming Tips

Elizabeth BautistaFebruary 14, 2025 0

¡Hablemos del amor en el lenguaje de programación en SAS Viya Workbench!

En el nuevo ambiente analítico bajo demanda, SAS Viya Workbench conduce directamente al aumento de la productividad, rendimiento y confianza entre los desarrolladores de la Inteligencia Artificial. Como uno de los recientes lanzamientos de SAS, Viya Workbench este es un ambiente de cómputo que fue pensado para desarrolladores y modeladores

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Spanish

Analytics | Programming Tips

Melodie RushFebruary 11, 2025 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Fitting a Support Vector Machine (SVM) Model

Fitting a Support Vector Machine (SVM) Model - Learn how to fit a support vector machine model and use your model to score new data In Part 6, Part 7, Part 9, Part 10, and Part 11 of this series, we fit a logistic regression, decision tree, random forest, gradient

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English

Learn SAS | Programming Tips

Rick WicklinFebruary 10, 2025 0

Find inflection points for a function that is known only at discrete points

A previous article describes how to use SAS to find the inflection points of a 1-D function that you can evaluate at any point. The function must be given by a formula (or by an algorithm) because the root-finding algorithm needs to evaluate the function at arbitrary locations. However, sometimes

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Learn SAS | Programming Tips

Rick WicklinFebruary 5, 2025 0

Find an inflection point for a function numerically

A SAS programmer asked if it is possible to numerically find an inflection point for a univariate function, f(x). Yes! This can be solved as a variation of a classic numerical root-finding problem. Recall that an inflection point is a value (call it x0) in the domain where the graph

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Analytics | Programming Tips

Rick WicklinFebruary 3, 2025 0

Use the Lambert W function to solve equations that involve exponential functions

I previously wrote an article about the Lambert W function. The Lambert W function is the inverse of the function g(x) = x exp(x). This means that you can use it to find the value of x such that g(x)=c for any value of c in the range of g, which

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Learn SAS | Programming Tips

Rick WicklinJanuary 27, 2025 0

Find the real roots of polynomials in SAS

A SAS programmer had many polynomials for which he wanted to compute the real roots. By the Fundamental Theorem of Algebra, every polynomial of degree d has d complex roots. You can find these complex roots by using the POLYROOT function in SAS IML. The programmer only wanted to output

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Learn SAS | Programming Tips

Rick WicklinJanuary 22, 2025 0

SAS tip: Use the hyphen and colon operators to specify multiple data sets on the SET statement

Here's a SAS tip for you. Most SAS programmers know that SAS provides syntax that makes it easy to specify a list of variables. For example, you can use the hyphen and colon operators to specify lists of variables on many SAS statements: You can use the hyphen operator (-)

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Analytics | Programming Tips

Melodie RushJanuary 14, 2025 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Fitting a Neural Network Model

Fitting a Neural Network Model - Learn how to fit a neural network model and use your model to score new data In Part 6, Part 7, Part 9, and Part 10 of this series, we fit a logistic regression, decision tree, random forest and gradient boosting model to the

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English

Analytics | Data Visualization | Learn SAS | Programming Tips

Rick WicklinJanuary 13, 2025 0

12 blog posts from 2024 that deserve a second look

In a previous article, I presented some of the most popular blog posts from The DO Loop in 2024. In general, popular articles deal with elementary topics that have broad appeal. However, I also write technical articles about advanced topics, which typically do not make it onto a Top 10

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English

Data Visualization | Programming Tips

Danny SprukulisJanuary 10, 2025 0

Utilizing SAS Viya’s Geocoding capabilities for multiple data configurations and languages

SAS' Danny Sprukulis takes you step-by-step through geocoding incomplete geographic data sources for proper visualization and through its additional capabilities.

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English

Analytics | Data Visualization | Learn SAS | Programming Tips

Rick WicklinJanuary 6, 2025 0

Top 10 posts from The DO Loop in 2024

In 2024, I wrote about 80 articles for The DO Loop blog. My most popular articles were about SAS programming, data visualization, and statistics. If you missed any of these articles, here is the "Reader's Choice Awards" for some of the most popular articles from 2024! SAS Programming The following

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Advanced Analytics | Programming Tips

Danny SprukulisDecember 20, 2024 0

Simulating theme park wait times within SAS Viya, creating a live solution for hospitality operations

SAS' Danny Sprukulis walks through how he developed a model theme park to simulate attraction wait times for operational decision-making.

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Hospitality

Analytics | Programming Tips

Rick WicklinDecember 18, 2024 0

Generate correlation matrices with specified eigenvalues

A previous article discusses how to generate a random covariance matrix with a specified set of (positive) eigenvalues. A SAS programmer asked whether it is possible to produce a correlation matrix that has a specified set of eigenvalues. After discussing the problem with a friend, I am happy to report

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinDecember 16, 2024 0

A normal Christmas tree

O Christmas tree, O Christmas tree, How lovely are your branches! SAS programmers have a long history of creating yuletide-themed graphics. Christmas trees are a popular image because of their simplicity. I admit that I have indulged more than once in this holiday tradition: An old-school ASCII art image A

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Learn SAS | Programming Tips

Chris HemedingerDecember 13, 2024 0

3 SAS Viya Workbench use cases for SAS Users

Review these three cool use cases for SAS users, built using SAS Viya Workbench. SAS and Python for better working together!

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English

Cloud | Programming Tips

Carlo ColaresDecember 12, 2024 0

Estratégias de implantação canary e blue-green para SAS Viya®

Conheça alguns conceitos e estratégias para implantação de soluções que aproveitam das capacidades da nuvem e de containers com o SAS Container Runtime (SCR) O SAS, líder global de dados e IA, atua há quase 50 anos no desenvolvimento de soluções analíticas. Há alguns anos, integra suas soluções ao universo

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Brazilian Portuguese

Advanced Analytics | Programming Tips

Rick WicklinDecember 9, 2024 0

Latin hypercube sampling in SAS

While researching the topic of Latin hypercube sampling (LHS), I read an article by Emily Gao (2019) that shows how to use PROC IML in SAS to perform the algorithm. It is possible to simplify Gao's implementation of Latin hypercube sampling in SAS while also making the computation more efficient.

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Analytics | Programming Tips

Rick WicklinDecember 2, 2024 0

A historical method of generating random normal variates

Decades ago, it was a challenge to generate (pseudo-) random numbers that had good statistical properties. The proliferation of desktop computers in the 1980s and '90s led to many advances in computational mathematics, including better ways to generate pseudorandom variates from a wide range of probability distributions. (For brevity, I

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Analytics | Learn SAS | Programming Tips

Rick WicklinNovember 20, 2024 0

Order two-dimensional vectors by using angles

Order matters. The order of variables in tables and rows of a correlation matrix can make a big difference in how easy it is to observed correlations between variables or groups of variables. There are many ways to order the variables, but this article shows how to display the variables

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Learn SAS | Programming Tips

Rick WicklinNovember 13, 2024 0

A vector-to-string function for SAS IML

A previous article discusses the MakeString function, which you can use to convert an IML character vector into a string. This can be very useful. When I originally wrote the MakeString function, I was disappointed that I could not vectorize the computation. Recently, I learned about the COMBL function in

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Programming Tips

Rodney BrownNovember 11, 2024 0

Interesting use cases of SAS job web applications

In the SAS 9.4 world, SAS Stored Processes (STP) were incredibly popular. An STP is a SAS program that is stored on a server and can be executed as required by requesting applications. On SAS 9.4, they were widely used for web reporting, analytics, building web applications, delivering packages to customers and publishing results to channels or repositories.

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Learn SAS | Programming Tips

Rick WicklinNovember 4, 2024 0

Levy flight and vectorizing a simulation in SAS

A previous article shows a simulation of two different models of a foraging animal. The first model is a random walk, which assumes that the animal chooses a random direction, then takes a step that is distributed according to a Gaussian random variable. In the second model, the animal again

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