PRT Blog

MATLAB Pattern Recognition Open Free and Easy

Dude Where's My Help?

Depending on your setup, you may have recently had one of the following happen:

  1. If you pulled the most recent version of the PRT since October 9, 2013, the PRT no longer shows up in the builtin MATLAB help-browser or
  2. If you updated to MATLAB 2013B, MATLAB freezes during startup.

    Here’s the skinny – there’s a bug in the new version of MATLAB (2013B) that, according to TMW:

This is a known issue with MATLAB 8.2 (R2013b) in the way that the MATLAB startup handles the info.xml file. There is a deadlock between the Help System initialization and the path changes (raised by the startup.m) at the start of MATLAB.

The result of this bug is that MATLAB seems to start up fine, but then just sits there, and never accepts inputs. This is pretty much as bad a bug as can be (besides wrong answers), since it makes MATLAB completely unusable, and you can’t even easily determine what is causing it since… MATLAB is unusable.

There is a patch to fix this bug, but if you don’t have the patch already installed it’s very difficult to figure out what is going wrong and it can be very frustrating. Alternatively, removing (or moving) the XML files will let MATLAB startup, but the automatic help search, prtDoc, etc. will no longer work. We thought that moving the XML files would cause the least amount of pain overall, so that’s what we did. Our XML files that used to live in prtRoot now live in fullfile(prtRoot,‘]xml’) which is by default not on the prtPath, so should not cause you any issues.

If you still want to use the PRT documentation in the MATLAB help browser, simply install the patch by following the instructions below, then move the .xml files from fullfile(prtRoot,‘]xml’) to prtRoot. That should get everything running!

Alternatively just use prtDoc instead of doc to open up the help in your browser (or the MATLAB web browser, depending on your version of MATLAB). For example:

prtDoc prtClassRvm

Sorry about any headaches anyone encountered, and a big “thank you” to Cesar from TMW who helped us get to the bottom of this quickly and professionally. Here are the patch installation instructions from Cesar:

To work around this issue, unzip the patch into your MATLAB root directory (most likely C:\Program Files\MATLAB\R2013b)

Patch Download