Matthew, would it make more sense to have unsafe-vector-ref (and related functions) be the more general function and unsafe-vector*-ref be the one that doesn't work on chaperoned vectors? That is just swap the definitions. That way user code that is already using unsafe-vector-ref (etc) will continue to work. As it stands, existing code that has unsafe-vector-ref (etc) will often still work (in the sense of not getting any error or crashing), but just gives the wrong results. For example, if you run science-test.ss from the examples directory in the science collection, there are no errors. But, some of the answers are wrong - for example the very first one, the gamma function. [In other cases, like the FFT routines, there are either run-time errors or crashes.] Anyway, if it isn't too late, I think swapping the definitions would make more sense and be safer. Doug <div class="gmail_quote">On Wed, Oct 20, 2010 at 8:56 AM, Matthew Flatt <<a href="mailto:mflatt@cs.utah.edu">mflatt@cs.utah.edu</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">At Wed, 20 Oct 2010 07:48:20 -0700, John Clements wrote: > > On Oct 20, 2010, at 7:39 AM, Doug Williams wrote: > > > I downloaded the pre-release version this morning - 10/20 (I believe it was > a build from 10/16). The plot package and plot extensions in the science > collection all work as expected. But, I am getting different numeric answers > for some of my science collection routines (for example, the gamma function) > and some of my newer code (for example, FFT) either fails with an error > message or DrRacket just dies. All of this code uses unsafe operations and the > problem may lie there somewhere. I'll try digging more deeply this evening. > > Focus first on uses of unsafe-vector-ref and unsafe-vector-set!. (Not the fx > and fl variants, just the plain ones). I wound up removing these from the FFT > code in order to get it to work. > > Check out bug PR 11264. > > Also, very late flash of insight: my response (getting rid of > unsafe-vector-ref and unsafe-vector-set!) might explain my performance issues > with the FFT library. </div>Overall, keep in mind that changes to vector contracts mean that vectors can be wrapped with chaperones. That's why `unsafe-vector-ref' may need to change to `unsafe-vector*-ref', and it may explain performance differences in general. </blockquote></div>