Monthly Archives: November 2009

Double.equals for NaN and -0.0

I just fixed two bugs in DrJava that had to do with boxed floating-point comparisons of NaN and -0.0. Both bugs had the same cause, a difference between the behavior of primitive ==and the equals method in DoubleandFloat. According to … Continue reading

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CSEE&T Paper Not Accepted

As expected, the paper I submitted for CSEE&T back in October did not get accepted. But that was a long shot anyway, and I already have something else for it in mind.

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Happy Thanksgiving

Happy Thanksgiving, everyone! I was fortunate to spend a wonderful day with Walid, Corky and Corky’s family. Thank you.

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Remembered Number Significance

Memories can be strange. A lot of people around me are probably now having memories triggered by (turkey) smells. I have memories triggered by numbers. Our Hudson build server just notified us of a unit test failure after a recent … Continue reading

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Mac OS X Race Condition in DrJava Start-Up

A few days ago, I noticed that double-clicking on a *.java file in Windows Explorer caused an AssertionError in DrJava. This wasn’t a huge issue, because it only shows with assertions enabled (i.e. -eain the JVM Arguments for the Main … Continue reading

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Huzzah for Sleeping In!

Today I slept in for the first time in a while. It’s been a tough fortnight, but we finished our PLDI 2010 submission. I feel it is considerably stronger than our previous submissions. Let’s home my confidence is justified.

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Open Source: Don’t Steal What You Can Have for Free

Open source is not the same as public domain material. It is not content that is not owned by anyone. The fact that we give something away for free does not allow you to just steal it. DrJava is an … Continue reading

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Halting Problem in the Style of Dr. Seuss

I found a proof in verse of the undecidability of the halting problem, in the style of Dr Seuss, written by Geoffrey K. Pullum (@ I’m delighted that I have a reason to cite Pullum on my blog here, because … Continue reading

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New Mint Release

I just created a new release of Mint and DrJava with Mint. JavaMint-r14577.tar.gz JavaMint-r14577-binaries.zip drjava-r5130-mint-r14577.jar There were some dramatic performance improvements in the Mint compiler thanks to base type lifting instead of performing cross-stage persistence for them. I also fixed … Continue reading

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Boring Backport

I’m in the process of porting some scientific code originally written in Fortran, which was then ported to Java, which was then ported to Habanero Java, back to Java, while maintaining a Habanero Java feature called array views. It’s incredibly … Continue reading

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In the Thresher!

In light of the upcoming registration period for the Spring 2010 semester, the Rice Thresher (our university newspaper) has published last spring’s course evaluations. It’s kind of cool to be listed in there, even though I probably won’t offer COMP … Continue reading

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Wikipedia and the Right to Know vs Right to Privacy

Sometimes it’s interesting to compare Wikipedia articles in different languages. I just read something about the last school shooting in Germany, the one in Winnenden in March 2009, and decided to search the web for it. The English Wikipedia article … Continue reading

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Twenty Years Ago

Twenty years ago, on 9 November 1989, the Berlin Wall came down. I remember the day, but the TV coverage doesn’t belong to my most intense childhood TV memories: It feels like this event is bracketed by stronger memories of … Continue reading

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Ridiculous Texas Bureaucracy That Doesn’t Make Anyone Safer

Last Tuesday I went back to the DPS to renew my drivers license — temporary visitors now have to do that once a year. I took exactly the same documents with me that allowed me to get a drivers license … Continue reading

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Lifting for Primitive and Boxed Types and Strings

When we examined the code that was generated for the sparse matrix multiplication benchmark of Mint, we noticed that variables containing loop indices had become cross-stage persistent (CSP) variables, which necessitated an array lookup. This was much more expensive than … Continue reading

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DrJava Interactions Pane Output Redirection

We got a question today about how the output of a Java program running in DrJava‘s Interactions pane could be redirected into a file, just like it could be done in a Unix or DOS shell: java Motion > motion.datThe … Continue reading

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