Emcee is an MIT licensed pure-Python implementation of Goodman & Weare's Affine Invariant Markov chain Monte Carlo (MCMC) Ensemble sampler and these pages will show you how to use it. This documentation won't teach you too much about MCMC but there are a lot of resources available for that (try this one). An emcee is the person who serves as the host of an event by introducing performers, speakers, or other participants. It comes from the abbreviation MC, which stands for master of ceremonies. Emcee is a less formal way of saying master of ceremonies. Briefing/Emcee/Proctor EPR Bullets - Briefed # psnl on childhood obesity, clinical implications/risk factors/patient outcomes-enhanced peers' scope of practice - Briefed 127 prsnl on suspicious e-mail; fine-tuned proper handling-enhanced sq info sec awareness/procedure. An emcee can play many roles, ranging from reading a few speaker introductions to writing remarks for all speakers. Each occasion has its own unique requirements and challenges, so confirm your role with the meeting organizer and be clear about your responsibilities and the organizer's expectations. Mar 26, 2020 - Explore Harish Arekar's board 'Emcee Script' on Pinterest. See more ideas about emcee, script, debut program.
Note: This tutorial was generated from an IPython notebook that can bedownloaded here.
Note
Some builds of NumPy (including the version included with Anaconda) will automatically parallelize some operations using something like the MKL linear algebra. This can cause problems when used with the parallelization methods described here so it can be good to turn that off (by setting the environment variable OMP_NUM_THREADS=1, for example).
With emcee, it's easy to make use of multiple CPUs to speed up slowsampling. There will always be some computational overhead introduced byparallelization so it will only be beneficial in the case where themodel is expensive, but this is often true for real research problems.All parallelization techniques are accessed using the pool keywordargument in the EnsembleSampler class but, depending on yoursystem and your model, there are a few pool options that you can choosefrom. In general, a pool is any Python object with a map methodthat can be used to apply a function to a list of numpy arrays. Below,we will discuss a few options.
In all of the following examples, we'll test the code with the followingconvoluted model:
This probability function will randomly sleep for a fraction of a secondevery time it is called. This is meant to emulate a more realisticsituation where the model is computationally expensive to compute.
To start, let's sample the usual (serial) way:
Multiprocessing¶
The simplest method of parallelizing emcee is to use themultiprocessing module from the standardlibrary. Toparallelize the above sampling, you could update the code as follows:
I have 4 cores on the machine where this is being tested:
We don't quite get the factor of 4 runtime decrease that you mightexpect because there is some overhead in the parallelization, but we'regetting pretty close with this example and this will get even closer formore expensive models.
MPI¶
Multiprocessing can only be used for distributing calculations acrossprocessors on one machine. If you want to take advantage of a biggercluster, you'll need to use MPI. In that case, you need to execute thecode using the mpiexec executable, so this demo is slightly moreconvoluted. For this example, we'll write the code to a file calledscript.py and then execute it using MPI, but when you really use theMPI pool, you'll probably just want to edit the script directly. To runthis example, you'll first need to install the schwimmbadlibrary because emcee no longerincludes its own MPIPool.
There is often more overhead introduced by MPI than multiprocessing sowe get less of a gain this time. That being said, MPI is much moreflexible and it can be used to scale to huge systems.
Pickling, data transfer & arguments¶
All parallel Python implementations work by spinning up multiplepython processes with identical environments then and passinginformation between the processes using pickle. This means that theprobability function must bepicklable.
Some users might hit issues when they use args to pass data to theirmodel. These args must be pickled and passed every time the model iscalled. This can be a problem if you have a large dataset, as you cansee here:
We basically get no change in performance when we include the dataargument here. Now let's try including this naively usingmultiprocessing:
Brutal.
We can do better than that though. It's a bit ugly, but if we just makedata a global variable and use that variable within the modelcalculation, then we take no hit at all.
That's better! This works because, in the global variable case, thedataset is only pickled and passed between processes once (when the poolis created) instead of once for every model evaluation.
- Briefed # psnl on childhood obesity, clinical implications/risk factors/patient outcomes--enhanced peers' scope of practice
- Briefed 127 prsnl on suspicious e-mail; fine-tuned proper handling--enhanced sq info sec awareness/procedure
- Briefed 2ID/CC f/discipline trends; drove peninsula-wide curfew policy f/10K USA/8 locations--team coined f/merit
- Briefed 60 CCMs on MTI duty; ID'd vital NCO qualities--sparked AF's 'Superior Amn DSD selection change'
- Briefed JTF/CC 2X wkly; SITREP advisor on cyber security/authorized mx time--built comm snapshot for CC
- Briefed retired 8FW/CC; demonstrated targeting pod advancements--showcased 'Take the Fight North' stance
- Briefed two Dedicated Crew Chief classes; explained MOC as a force multiplier--polished own comm skills
Emcee1153
- By name selected/briefed Aviano PA 2W1 AFSC; lauded career fields impact--perpetuated Wg motto 'AV3D'
- Dedicated 20 hrs to mentor 110 hometown high school students; enhanced civilian knowledge of AF life/msn
- Defense ambassador...educated 60+ at FTAC/4 CC calls--increased awareness of ADC mission & mbr rights
- Defense ambassador; briefed 500+ at FTAC/Right Start/CC Call--all Amn aware of rights & defense services
- Defense ambassador; briefed 500+ mbrs at FTAC/Amn and NCO Enhancement--ADC credibility strengthened
- Defense ambassador; educated 1000+ at FTAC/newcomers--increased awareness of mbr rights/ADC mission
- Displayed outstanding military image; handpicked to represent AMXS on Aviano website's 'Airman Spotlight'
- Educated Croatian AF ldrs on MOC prgms, acquainted 12 officers--US-NATO alliance/mil force strengthened
- Eloquent speaker! Briefed ADC/DP roles to 50+ SNCO Induction Seminar attendees...enhanced defense image
- Emceed AMXS CC call; recognized 16 Amn/presnt'd five decorations--upheld tradition/decoration ceremony
- Engaged SNCO; fielded Q&A session for 14 USAF Academy Cadets--cultivated future military officer corps
- Face of Wing! CSAF visit POC/'13 Annual Awds Emcee honoring 'best of the best'--coined by FW CC/CSAF
- Facilitated Combat Nighthawk prgrm; briefed daily participants--enabled 31 FW to meet USAFE program goal
- Guest speaker during hometown HS graduation; mentored grads on military core values--superb AF role model
- Handpicked to brief USAFE/CC mx capes; recv'd CC coin for comm skill--aided AMXS AF-lvl Mx Eff Awd
- Honed speaking techniques; narrated 31 AMXS Cmdr Call--guided event format/recongnized 3 exemplary Amn
- Hosted Rotary Club BPC event; coord'd w/PA to honor civic leaders--briefed wing msn in Italian to 32 guests
- Inspires troops--picked to brief 50+ MSgt-selects on discipline & welcomed 1,300+ FTAC Amn/newcomers
- Logistics Officer Asso Pres; org'd 3 factory/2 unit tours, Wg/CC lunch--expanded logistical insight of 36 offcrs
Emcee Meaning
- Office ambassador; briefed 300+ at FTAC & CC calls...strengthened ADC mission/individual rights awareness
- Orchestrated ADAPT brief; organized 2 hr trng/'drunk cart'/alcohol effects information--safeguarded 82 Amn
- Practiced public speaking w/Amn then put to use; led 6 mbr CC call tm/MC'd event--boosted morale 200 mbrs
- Public face of 178 ISRG; briefed ATAG/SCCM/60+ mbrs at Ohio ELS--enhanced mbrs awareness of Intel missions
- Public face of the ADC; briefed 200+ at monthly FTAC/ALS/ CC call briefings...inspired trust and confidence
- Selfless! Volunteered as emcee MPOY 2010 banquet; embodied AF Heritage--role model for all MXG pers
- Sought after! Briefed Enlisted Force Structure & Amn responsibilities/3 FTAC crses--developed 43 future ldrs
- Taught 20 person basic comp/CSA class; dvlpd hands on/presentation--increased base network sec knowledge
- Touted phase dock for 7th AF Command Chief; briefed maintenance stds--received coin for professionalism
- Vol'd as coordinator for Aviano's Town Hall meeting; POC/coord'd community events--enhanced wg cohesion
Cough up some EPR bullets, you slackers!
- Handpicked to brief USAFE/CC mx capes; recv'd CC coin for comm skill--aided AMXS AF-lvl Mx Eff Awd
- Honed speaking techniques; narrated 31 AMXS Cmdr Call--guided event format/recongnized 3 exemplary Amn
- Hosted Rotary Club BPC event; coord'd w/PA to honor civic leaders--briefed wing msn in Italian to 32 guests
- Inspires troops--picked to brief 50+ MSgt-selects on discipline & welcomed 1,300+ FTAC Amn/newcomers
- Logistics Officer Asso Pres; org'd 3 factory/2 unit tours, Wg/CC lunch--expanded logistical insight of 36 offcrs
Emcee Meaning
- Office ambassador; briefed 300+ at FTAC & CC calls...strengthened ADC mission/individual rights awareness
- Orchestrated ADAPT brief; organized 2 hr trng/'drunk cart'/alcohol effects information--safeguarded 82 Amn
- Practiced public speaking w/Amn then put to use; led 6 mbr CC call tm/MC'd event--boosted morale 200 mbrs
- Public face of 178 ISRG; briefed ATAG/SCCM/60+ mbrs at Ohio ELS--enhanced mbrs awareness of Intel missions
- Public face of the ADC; briefed 200+ at monthly FTAC/ALS/ CC call briefings...inspired trust and confidence
- Selfless! Volunteered as emcee MPOY 2010 banquet; embodied AF Heritage--role model for all MXG pers
- Sought after! Briefed Enlisted Force Structure & Amn responsibilities/3 FTAC crses--developed 43 future ldrs
- Taught 20 person basic comp/CSA class; dvlpd hands on/presentation--increased base network sec knowledge
- Touted phase dock for 7th AF Command Chief; briefed maintenance stds--received coin for professionalism
- Vol'd as coordinator for Aviano's Town Hall meeting; POC/coord'd community events--enhanced wg cohesion
Cough up some EPR bullets, you slackers!
Emceeing
Emcee Python
