All posts by Erik Erhardt

Erik Barry Erhardt, PhD, is an Associate Professor of Statistics at the University of New Mexico Department of Mathematics and Statistics, where he has served as Director of the Statistics Consulting Clinic, and is currently Director of the Biostatistics and NeuroInformatics (BNI) Core for the second phase of the Center for Biomedical Research Excellence (COBRE) in Brain Function and Mental Illness at the Mind Research Network. His research interests include Bayesian and Frequentist statistical methods for stable isotope sourcing and brain imaging. Erik is a Howard Hughes Medical Institute Interfaces Scholar collaborating in interdisciplinary research and offering consulting services in statistics.

Penalized-x, new pool solitaire game

I developed a solitaire game for pool (pocket billiards) that stresses the importance of making every shot count and developing your balls-per-inning potential for those of us who often run between 2 and 10 balls, based on straight pool.  I call it “Penalized-x”, where “Penalized-5” would specify 5 penalty balls. The rules:
  1. Rack all 15 in the standard way, start with cue on the head spot.
  2. Choose a number of penalty balls, a number of balls from 1 to 14.
  3. All shots except the break must be made with the intention of sinking a called ball in a called pocket; shots taken explicitly to spread the balls are not allowed.
  4. On any miss, foul, or scratch return the number of penalty balls to the table, spotted in the standard way starting at the foot spot along the foot line to the foot of the table, and continuing at the foot spot toward the head of the table.
  5. On a scratch, additionally, the cue is placed on the head spot if unobstructed, else on the center spot if unobstructed, else in the kitchen.
  6. The game ends when the last ball is potted with a legal stroke.
  7. The game is scored by the two numbers balls/innings, which also gives balls per inning. For example, 78/23=3.39 indicates 78 balls potted in 23 innings for 3.39 balls per inning.
Leave a comment to let me know what you think, or if you have any suggestions for improvement. My games so far: Penalized-5 (date – balls/innings=bpi)
  1. 20081230 – 78/23=3.39, end run 9,11
  2. 20081231 – 45/12=3.75, end run 15
  3. 20090101 – 71/21=3.38, end run 15
  4. 20090101 – 61/15=4.07, end run 15
  5. 20090102 – 270/63=4.28, end run 7,13 (made it to 1 ball 3 times)

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The Calamitous Milkcrate Caper, a contra dance

The Calamitous Milkcrate Caper

by Erik B. Erhardt, 2003.05.27 Duple Improper Contra Dance [Pulses Call] A1: 4 Circle Left 1/2 4 Gent Roll Partner [Lady] Left into (no sashay, Gents are anchored in place) 4 Gents Chain across by the Right [hand] (the Gents are doing a Ladies chain) 4 Ladies Courtesy turn Gents (give Left hands, wheel around) A2: 4 Circle Right 1/2 4 Lady Roll Partner [Gent] Right into (no sashay, Ladies are anchored in place) 8 Ladies Left shoulder 1/2 Hay B1: (the tease) 6 Gypsy Partner 3/4 around (until the gents are facing in) 2 Gents cross set (by right shoulders) into 8 Swing Neighbor on Lady’s side B2: 4 Ring Balance 4 Active Lady California twirl Partner/Gent (Lady lift right hand, gent turn under, and pull into a swing) 8 Actives Swing while Inactives cast alone over outside shoulder [can alternate actives and inactives role in B2 if long sets and very sharp dancers, caller may need to cue actives/inactives for swing throughout] Dance Notes:
  • This dance was written with gender role reversal in mind. It’s about time the guys get the dance action! Also, if the gypsy is done meaningfully, it can be a real tease.
  • It’s probably worth a little extra instruction to get the Gents Chain across correct. Most people only dance one gender role. As such, they have difficulty when called upon to reverse roles. I suggest two walk-thrus of the Gents chain across. The first one suggest the traditional courtesy turn with the right hands on the waist/lower back. The second one suggest an underarm twirl. This will give the dancers a wider vocabulary of moves.
  • Also, I would suggest that if the man is much taller than the lady, that they resort to the traditional courtesy turn rather than the underarm twirl to avoid injury. In this case there is a nice “whip” twirl where, if they take hands in front for the turn, at the end the lady can whip the guy for an unspotted spin (guy spins counter-clockwise) at the end. More advanced dancers will find this on their own.
  • 12/30/09 – Made two corrections (B1 gypsy 1/2, B2 Actives only Cali turn) and expanded explanations.
  • 2008: I’m starting to dance again, after developing (2004ish) and having surgery (Dec 2006) to remove a Morton’s Neuroma in my left foot from dancing in beautiful shoes that were too narrow; it’s hard to find dance shoes in a 11-4E. To celebrate, here’s a contra I wrote some years ago, which I first called at CCDS 2009.

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Original Music from the 1990s

In high school I mostly played guitar, and in college I mostly composed music on the computer. Here’s a selection of that work.

Liquid Mazes, 1993 (High school)

I wrote (most) and recorded these songs while in high school. I played guitar, was significantly influenced by Steve Vai, Joe Satriani, and JS Bach. “Joy” and “Satch” are probably my favorites. My mom was holding a dieing tape recording the the audience for “Satch”, which is why the speed and pitch both increase slightly over the course of the recording.
Title Formats Recommended
One Funny Dream mp3
Love is More Thicker Than Forget mp3 *
Laura’s Lullaby mp3 *
The Joy of Dawn mp3 *
Ballarina 12/24 mp3
Eleven at Night mp3 *
Bach 2-part Inventions 8 and 13 (live) mp3
Bluesion mp3 *
We Are People mp3
Satch Covers (live) mp3 **

Computer Music, college (1995-1997)

Encore music composing software seemed pretty advanced, even over ten years ago, and enabled me to compose some simple multipart pieces. You can listen quickly from the “mid” link (for midi) and see the notation using “ps” or “pdf”. The first two and the last are probably my favorite.
Date Number Title Formats Recommended
19950714 EBE001 Prima Fuga en G enc mid ps pdf *
19950716 EBE002 Fugue for Frank and Kathy enc mid ps pdf *
19950805 EBE003 Fugue in C (with Brian Coakley) enc mid ps pdf
19960120 EBE004 Song for Kent and Kate enc mid ps pdf *
19960131 EBE005 kamawanai (it doesn’t matter) enc mid ps pdf
19960305 EBE006 For Dimitri enc mid ps pdf
19960305 EBE007 Study in C minor enc mid ps pdf
19960223 EBE008 The Sun came out enc mid ps pdf
19960422 EBE009 Song for Spring enc mid ps pdf
19961209 EBE010 Choral 1 enc mid ps pdf *
19961215 EBE011 Choral 2 enc mid ps pdf *
19970305 EBE012 Early Morning Play enc mid ps pdf *
19970314 EBE013 At the Carnival enc mid ps pdf *
19970428 EBE014 Fugue in D minor enc mid ps pdf **

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R> print(“Hello, world”)

[caption id="attachment_34" align="alignright" width="149" caption="C MPI implementation of waves equation on 16 processors, init + 10 time steps."]courses[/caption] Thanks to Matthew Bohnsack for setting my site up on wordpress. Matt and I worked together on projects in CS 442 Introduction to Parallel Processing in Fall 2006. He’s hosted my site since April, 2007, and there have been terrific benefits. First, the server is beautifully configured and fast, and he’s given me plenty of space. Working with him has allowed me to provide my SISUS software prototype, which is an R package which I haven’t released, yet. He discusses his implementation of the software needed in his blog post. He is quick to respond, works meticulously, and understands the big picture as well as the individual pixels.
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