Constrained MDPs and the reward hypothesis

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It's been a looong ago that I posted on this blog. But this should not mean the blog is dead. Slow and steady wins the race, right? Anyhow, I am back and today I want to write about constrained Markovian Decision Process (CMDPs). The post is prompted by a recent visit of Eugene Feinberg , a pioneer of CMDPs, of our department, and also by a growing interest in CMPDs in the RL community (see this , this , or this paper). For impatient readers, a CMDP is like an MDP except that there are multiple reward functions, one of which is used to set the optimization objective, while the others are used to restrict what policies can do. Now, it seems to me that more often than not the problems we want to solve are easiest to specify using multiple objectives (in fact, this is a borderline tautology!). An example, which given our current sad situation is hard to escape, is deciding what interventions a government should apply to limit the spread of a virus while maintaining economic
6 comments

Keynote vs. Powerpoint vs. Beamer

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A few days ago I decided to give Keynote, Apple's presentation software, a try (part of iWork '09). Beforehand I used MS Powerpoint 2003, Impress from NeoOffice 3.0 (OpenOffice's native Mac version) and LaTeX with beamer. Here is a comparison of the ups and downs of these software, mainly to remind myself when I will reconsider my choice in half a year and also to help people decide what to use for their presentation. Comments, suggestions, critics are absolutely welcome, as usual. Btw, while preparing this note I have learned that go-oo.org has a native Mac Aqua version of OpenOffice. Maybe I will try it some day and update the post. It would also be good to include a recent version of Powerpoint in the comparison.

Stability

  • Keynote: Excellent
    After a few days of usage, so take this statement with a grain of salt..
  • MS Powerpoint 2003: Excellent
  • Impress: Poor
    Save your work very often
  • Beamer: Excellent

Creating visually appealing slides, graphics on slides

  • Keynote: Excellent
    Positioning rulers help a lot. The process is really smooth. Keynote forces you to use less text. Built in templates are professional looking. Adding presentation graphics (tables, basic charts) is very easy. Cooler (technical drawing) better done with OmniGraffle. You can also easily animate the graphics, tables. Overall, very impressive.
  • MS Powerpoint 2003: Good
    Aligning to other objects is more cumbersome than in Keynote. The quality of fonts, color palettes, templates is not as good in Keynote.
  • Impress: Good
    Same as MS Powerpoint, maybe somewhat below (but the difference is not big).
  • Beamer: Poor
    The fonts and styles (templates) are great. However, creating slides with lively graphic is a nightmare (due to the lack of a GUI): You will end up with a few standard layouts, you will in general not use graphics, let alone animated graphics (or you will spend days on creating your slides). Also, departing from the styles is difficult and I am just bored of some of these styles that everyone seems to use.

LaTeX (math) support

  • Keynote: Poor
    Supported through LatexIt (free), but overall a cumbersome process. Details below.
  • MS Powerpoint 2003: Medium
    Supported through TexPoint (commercial, USD30) process is roughly same as with LatexIt and Keynote, slightly better integration.
  • Impress: Medium
    Supported through OOoLatex (free), same as MSPowerPoint + TexPoint, the integration is slightly better.
  • Beamer: Excellent
    Beamer is built for this!

Animations

  • Keynote: Near perfect
    Magic slide transition helps a lot with continuity across slides. What does this do? If you have the same object on two consecutive slides, Keynote will create an animation, keeping the object on screen and flying it to its new position. Works with multiple objects, too. I have found this very helpful for presenting a multi-slide argument. In general, Keynote animations are slick, polished, the flexibility is great. I lack some features of Beamer, such as animated highlighting, in-place replacement of some text (these can all be simulated with the existing tools, but with difficulty only).
  • MS Powerpoint 2003: Basic
    I miss Keynote's magic transitions. In general, Keynote is richer in animations. Again, some features of Beamer would be nice to have.
  • Impress: Weak
    Impress is inferior in terms of its animation caps to MS Powerpoint
  • Beamer: Good
    If only someone added support for magic transitions between slides. Some other cool effects would also come handy.

Dual screen presentation support

The idea is to show notes, time left in addition to the current and next slide on your screen, while showing the current slide on the big screen.
  • Keynote: Excellent
    Keynote supports double screen presentations natively. If you need to swap displays, go on the notes screen in the options menu. This will be on the big screen, obviously, if you need to swap the the screens.
  • MS Powerpoint 2003: Not available
    I have no experience with this feature of MS Powerpoint. Maybe you can use and add-on or something, but the basic software does not support it. I am pretty sure newer versions of Powerpoint must support this.
  • Impress: Excellent(?)
    The "Sun Presenter Console" extension supposedly supports dual screen presentations just like Keynote, but I have never had the chance to test it. Hence, the question mark. Some posts on the internet indicate that the extension might leak memory.
  • Beamer: Basic support
    Use Splitshow for this purpose. However, as far as I know, you cannot show the current time or the time remaining on the notes screen.

Interoparability

I want to put my presentations on the web so that people can look at them no matter what (major) operating system they use, without loosing animations or any other features. Another desired feature is the ability to create a compact, printable version of the slides: That is, if you have animations spanning multiple slides, somehow they should get handled intelligently. There is a tradeoff here: The more animation rich your slides are, the more bloated/complicated your printout will be.
  • Keynote: OK
    Proprietary file format. This is my biggest complaint. A keynote presentation is a keynote presentation. Apple likes to lock you in. Export to PDF and PPT works relatively well, but will lose some features of the presentation, like the cool animations. Exporting to PDF without animations to create printable versions seems to work well.
  • MS Powerpoint 2003: Good
    Free powerpoint viewers exist that can play any PPT file. Export to PDF will again lose some features.
  • Impress: Good
    Same as powerpoint.
  • Beamer: Excellent
    Produces PDF outputs: The presentations can be viewed on any computer! Also, the source is later, beamer is available on all systems. Add [handout] to the style and beamer will create an animation free version of your slides that works almost all the cases.

More about using formulae in Keynote (and why it sucks)

I used LatexIt which produces a PDF that can be embedded into the presentation. Style is not matched automatically. The PDF contains the latex source for the formulae, copy paste it back to LatexIt to edit it. When done with the edit, you need to drag and drop the formula back into Keynote. This sucks, since you need to delete the original that you have edited, reposition the new formula and reapply animations if you had any. Horrible.

Another issue is that the source saved with the formula by default does not have the preamble, thus using a command set specific to a presentation is difficult to achieve (you have to set this up manually). Another major headache is that you will not be able to use inline formula (a text is either in LaTeX, or in Keynote, the fonts in general do not match and mix well, alignment is a nightmare), nor will you be able to animate easily formulae (e.g., displaying a multiline formula line by line requires you to split the formula into multiple PDFs and use Keynote animations to show them one by one; this is problematic because formula alignment by hand is time consuming).

Comments

  1. Unknown24 November 2009 at 19:44

    Powerpoint has Presenter View, which puts your presentation on the screen with a separate view of the slides with notes, a timer, and so on. The only thing that I wish it supported was the ability to point with your mouse on the slide view and have a pointer appear on the screen view.

    ReplyDelete
  2. Csaba Szepesvári28 November 2009 at 10:55

    Thanks Tom for the info.
    I should test this in Keynote.
    One another annoyance with Keynote: Imagine you need to add LaTeX labels to some graphics that you create with Keynote. You start in some size, create everything. Then you wish to resize the while thing (formulae and graphics) in a proportional manner. This does not work (at least it did not work for me).

    ReplyDelete
  3. Anonymous17 December 2009 at 04:34

    I'm suprised you are using Powerpoint 2003 as the comparison when Powerpoint 2007 is far more powerful.
    I'm a long time PC user and just bought a MAC.....couldn't wait to open Keynote as I'd heard so much about it and very, very disappointed. It lacks most of the quick and easy things I can do in PPT07...no Smartart, very few standard shapes, no easy to see colour palettes, very limited shape effects (where is 3D??) no quick styles, and so on.

    I haven't tried it yet but the slide transition seems to be far better in Keynote.

    I really want to like Keynote but very disappointed right now. Ihoep someone can prove me wrong as I'd really like to like Keynote!

    ReplyDelete
  4. Csaba Szepesvári28 December 2009 at 01:19

    I compared Powerpoint 2003 because I have experience with that. Maybe, one day I will try Powerpoint 2007 and then will report back.

    ReplyDelete
  5. Jai Pillai23 July 2010 at 04:52

    Relevant post and good comparisons.
    I always have this dilemma. I want to use Beamer as it looks more professional. But ur slides look so dry, with out the animations possible with Powerpoint.

    ReplyDelete

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