Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Makarius
On 02/11/16 17:30, Lawrence Paulson wrote: > > I think it would be quite straightforward to try the experiment of > building Isabelle with the new compiler, but I would need some help with > our present setup I've been working with David Matthews for some weeks to see the new compiler and

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Lawrence Paulson
Okay then. Obviously proceed with caution, as always. MetiTarski also has high standards, and doesn’t have the added security of a kernel architecture. Every significant change is checked by regression testing using tools that highlight significant changes in the runtime of the full test

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Tobias Nipkow
On 02/11/2016 15:58, Lawrence Paulson wrote: I have to say, I’m absolutely mystified by the response to my suggestion. This is a nontrivial change in the semantics. The programming language community has tried to get away from the "looks ok" approach to "here is some sound reasoning why it

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Makarius
On 02/11/16 15:58, Lawrence Paulson wrote: > I have to say, I’m absolutely mystified by the response to my suggestion. Why? I did not reject the idea, but only put it into the context of Isabelle. MetiTarski is a small research experiment, but Isabelle a huge and complex software product, with

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Lawrence Paulson
I have to say, I’m absolutely mystified by the response to my suggestion. MetiTarski, which during execution relies heavily on large integers, nevertheless benefits to the tune of 30% to having all other integers fixed-precision. During its execution, Isabelle makes very heavy use of small

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Makarius
On 02/11/16 15:30, Lawrence Paulson wrote: > > I actually can’t think of many places where Isabelle would need large > integers, so it would probably benefit even more than MetiTarski does. "Can't think of" merely indicates a lack of empirical tests, against the Isabelle repository and AFP.

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Tobias Nipkow
I value the guarantees we get from having proper integers a lot. No worries. With bounded integers, we would have to worry about what happens to over/underflow exceptions: can handlers for such exceptions in a piece of user code lead to unsoundness in the inference system? At first it seems

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Lawrence Paulson
The difference is substantial and uniform. I attach log files summarising MetiTarski’s performance by nearly 900 examples. You will note that total CPU time is way down, and problems consistently run much faster using fixed-precision arithmetic. Both runs involve the new version of Poly/ML,

Re: [isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Makarius
On 02/11/16 13:07, Lawrence Paulson wrote: > David Matthews is working on a new release of Poly/ML in which the default > type of integers is fixed-precision. A configuration option can restore the > former set up, but that might be a mistake: I modified MetiTarski to use > large integers only

[isabelle-dev] Integers in Poly/ML

2016-11-02 Thread Lawrence Paulson
David Matthews is working on a new release of Poly/ML in which the default type of integers is fixed-precision. A configuration option can restore the former set up, but that might be a mistake: I modified MetiTarski to use large integers only where needed and saw runtime decrease by around