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Waynette TubbsNovember 9, 2012 0

Friday's Innovation Inspiration - Parsing for 100% comparison

Did I tell you that I went to Andrew Kuligowski's hands-on workshop while I was at MWSUG 2012? Actually, I only attended the first portion of his session; it didn't make sense for me to take up a computer since I'm not a programmer. His workshop was to teach users how to parse useful data from unusual

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Rick WicklinNovember 7, 2012 0

Constructing block matrices with applications to mixed models

The other day I was constructing covariance matrices for simulating data for a mixed model with repeated measurements. I was using the SAS/IML BLOCK function to build up the "R-side" covariance matrix from smaller blocks. The matrix I was constructing was block-diagonal and looked like this: The matrix represents a

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Advanced Analytics | Data Visualization | Programming Tips

Angela HallNovember 5, 2012 0

Cleaner OLAP cube physical folder structures

Each spring and fall, I start clearing out the kid's small clothes, old toys, etc. It can sometimes go too far and reach into my "digital pack-rat" issues. (Wait, what does that mean? Well, just ask the person who last week requested detail on a project I worked 3 years

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Udo SglavoNovember 2, 2012 0

Divide and Conquer: Segmenting Time Series for Improved Forecasts

We all have some sort of intuitive idea of what time series data is – it’s a bunch of measurements or observations that are marked by a time stamp – we know when the measurement was taken, as well as what was measured. This natural temporal ordering of the data

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Waynette TubbsNovember 2, 2012 0

Friday's Innovation Inspiration - Macros at Coder's Corner, MWSUG 2012

As part of the Friday's Innovation Inspiration (FII) series, I've decided to present a few SAS techniques and problem solvers that you labeled as innovative or 'inspirational'. These are pretty easy to find: I've done some digging through the Best Contributed Papers. I know you haven't read them all, so

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Rick WicklinOctober 31, 2012 0

Compute the log-determinant of a matrix

The determinant of a matrix arises in many statistical computations, such as in estimating parameters that fit a distribution to multivariate data. For example, if you are using a log-likelihood function to fit a multivariate normal distribution, the formula for the log-likelihood involves the expression log(det(Σ)), where Σ is the

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Advanced Analytics | Data Visualization | Programming Tips

Angela HallOctober 29, 2012 0

So many autoexecs; three tips for BI administrators

BASE SAS users are already familiar with the autoexec file. This is a .sas file that typically resides in the installation folder of the SAS executable. Instructions for setting it up in UNIX, Windows, and other environments is readily available on the SAS website. In SAS BI configurations there are

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Tonya BalanOctober 19, 2012 0

Best Practices for Big Data: Learning from the Past While Looking to the Future

I’ve heard it said that the only thing you can count on in life is change. The same can be said of technology. Change is certain, and the rate of change seems to accelerate with each passing year. Change requires us to adapt, but as we race to keep up with

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Waynette TubbsOctober 19, 2012 0

Friday's Innovation Inspiration - Fish mating calls?

I'm going to handle this Friday's Innovation Inspiration a bit differently from the way I usually do; rather than helping you find information so that you can try this on your own, I'd like to know what you would use to display fish mating calls. Obviously you would need a few

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Advanced Analytics | Data Visualization | Programming Tips

Angela HallOctober 15, 2012 0

Go on a date with SAS BI Dashboard, part 2

Last week I provided the steps for how to go on a date, at least by using dynamic prompts in BI Dashboard. Now that you have seen how to create them, lets discuss making them smarter. For this example, the customer is asking for two prompts to affect a single

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Advanced Analytics | SAS Events

Polly Mitchell-GuthrieOctober 12, 2012 0

Is experimental design the red-headed stepchild of modeling?

Andy Pulkstenis of State Farm thinks it is, stating that this red-headed stepchild among modeling technques is where predictive modeling was ten years ago. He opened his talk, "Do You Know or Do You Think You Know? Creating a Testing Culture at State Farm," at the A2012 conference in Las Vegas with

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Rick WicklinOctober 10, 2012 0

Playing "craps" with unfair dice

Last week I wrote a SAS/IML program that computes the odds of winning the game of craps. I noted that the program remains valid even if the dice are not fair. For convenience, here is a SAS/IML function that computes the probability of winning at craps, given the probability vector

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Advanced Analytics | SAS Events

Radhika KulkarniOctober 5, 2012 0

An invitation to look inside advanced analytics at SAS

A year ago I set out to periodically blog from my perspective of leading R&D for our advanced analytics software. I invited SAS colleagues who also work in various areas of advanced analytics to blog on their own interesting conversations with each other and with customers about the intersection of

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Waynette TubbsOctober 5, 2012 0

Friday's Innovation Inspiration - BUBBLE option?

I have to say that I've never heard of the Bubble option, so I looked it up on support.sas.com (my go-to place for searches on customer problems or to simply to learn something about SAS). The search led me to documentation for the statement options in SAS ODS Graphics. So, I assume the

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Rick WicklinOctober 4, 2012 0

Dice probabilities and the game of "craps"

Gambling games that use dice, such as the game of "craps," are often used to demonstrate the laws of probability. For two dice, the possible rolls and probability of each roll are usually represented by a matrix. Consequently, the SAS/IML language makes it easy to compute the probabilities of various

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Advanced Analytics | SAS Events

Waynette TubbsSeptember 28, 2012 0

Friday's Innovation Inspiration - The big C PROCs: CONTENTS AND COMPARE

I chose this Post-It note this week because it reminded me of a MWSUG paper presentation that I listened to and wrote about. Patricia Hettinger presented "New vs. Old - Under the Hood with PROCs CONTENTS and COMPARE" in the Data Management and Data Mining section. I didn't do it justice in my

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Rick WicklinSeptember 26, 2012 0

A surprising result: The expected number of uniform variates whose sum exceeds one

I was recently flipping through Ross' Simulation (2006, 4th Edition) and saw the following exercise: Let N be the minimum number of draws from a uniform distribution [until the sum of the variates]exceeds 1. What is the expected value of N? Write a simulation to estimate the expected value. For

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Rick WicklinSeptember 24, 2012 0

Grouping observations based on quantiles

Sometimes it is useful to group observations based on the values of some variable. Common schemes for grouping include binning and using quantiles. In the binning approach, a variable is divided into k equal intervals, called bins, and each observation is assigned to a bin. In this scheme, the size

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Waynette TubbsSeptember 21, 2012 0

Friday's Innovation Inspiration - That's a COPY

Diane Olson, from SAS, wrote a SAS Global Forum paper in 2011 that seems ready-made for this SAS user's Post-It note. Olson wrote about PROC COPY and PROC APPEND. In her paper, she lets you in on the inside tricks on how to clone your data set to the same library, copy

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Rick WicklinSeptember 17, 2012 0

Filling the lower and upper triangular portions of a matrix

If you use a word three times, it's yours. -Unknown When I was a child, my mother used to encourage me to increase my vocabulary by saying, "If you use a word three times, it's yours for life." I believe that the same saying holds for programming techniques: Use a

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Rick WicklinSeptember 6, 2012 0

Testing for equality of sets

Ah! The joys of sets! It is easy to test whether two vectors are equal in SAS/IML software. It is only slightly more challenging to test whether two sets are equal. Recall that A and B are equal as sets if they contain the same elements. Order does not matter.

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Rick WicklinAugust 20, 2012 0

How to return multiple values from a SAS/IML function

The SAS/IML language supports user-defined functions (also called modules). Many SAS/IML programmers know that you can use the RETURN function to return a value from a user-defined function. For example, the following function returns the sum of each column of matrix: proc iml; start ColSum(M); return( M[+, ] ); /*

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Rick WicklinAugust 16, 2012 0

Extract the lower triangular elements of a matrix

It is common to want to extract the lower or upper triangular elements of a matrix. For example, if you have a correlation matrix, the lower triangular elements are the nontrivial correlations between variables in your data. As I've written before, you can use the VECH function to extract the

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Advanced Analytics | SAS Events

Waynette TubbsAugust 10, 2012 0

Friday's Innovation Inspiration - Automated reports and poster ideas!

This Post-It Note reminds me of a presentation at SAS Global Forum 2012 about automating reports. Of course, these Post-It Notes always remind me of presentations. This week, instead of pointing you to a bunch of past presentations, I'm going to challenge you to use this note as an idea

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Waynette TubbsAugust 3, 2012 0

Friday's Innovation Inspiration - Ratemaking

In this Innovation Inspiration, a SAS user has developed the insurance rating plans for a country using predictive modeling. How exciting! Additionally, the system adjusts based upon actual experience. This is quite the accomplishment given the complexity of the ratemaking for even a small geographical territory. The comments section reveal the identity of this innovator. Check it out.

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Rick WicklinJuly 11, 2012 0

Visualize the bivariate normal cumulative distribution

When you are working with probability distributions (normal, Poisson, exponential, and so forth), there are four essential functions that a statistical programmer needs. As I've written before, for common univariate distributions, SAS provides the following functions: the PDF function, which returns the probability density at a given point the CDF

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Rick WicklinJuly 9, 2012 0

Reordering data to match a target order

Suppose that you have two data vectors, x and y, with the same number of elements. How can you rearrange the values of y so that they have the same relative order as the values of x? In other words, find a permutation, π, of the elements of y so

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Rick WicklinJuly 5, 2012 0

Compute the multivariate normal density in SAS

I've been working on a new book about Simulating Data with SAS. In researching the chapter on simulation of multivariate data, I've noticed that the probability density function (PDF) of multivariate distributions is often specified in a matrix form. Consequently, the multivariate density can usually be computed by using the

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Waynette TubbsJune 29, 2012 0

Friday's Innovation Inspiration - Extracting data from Oracle

It's so important for companies to build what customers want rather than build a product and then convince the market to buy it. So I love it when I hear or read remarks like the one below - SAS has grown with me. That means that we have listened to

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