Re: [Haskell-cafe] The case of the missing module
Hi, import Paths_haddock( getDataDir ) Haddock requires to be built with Cabal (which generates this module), and as far as I can remember, its a Cabal that isn't released anywhere. When I did some work on haddock I commented this out, and made getDataDir return an empty list and then made sure to set the -l flag (I think) and was able to work around this. Of course, the solution is to get Cabal working. I broke Cabal long ago, but you might have more luck. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] ANNOUNCE: An index-aware linear algebra library in Haskell
It is really counterintuitive! I will study carefully your library and the Implicit Configurations paper. Using static dimension checking we can write very solid code for matrix computations... However, I don't know how to write some definitions. For instance, this is ok: m = $(dAM [[1,2,3]]) but with: x = [[1,2,3]] :: [[Double]] m1 = $(dAM x) m2 = listMat x main = do print m1 print m2 I get: Vector/examples.hs:35:11: GHC stage restriction: `x' is used in a top-level splice, and must be imported, not defined locally In the first argument of `dAM', namely `x' In the definition of `m1': m1 = $[splice](dAM x) Vector/examples.hs:40:10: Inferred type is less polymorphic than expected Quantified type variable `m' escapes Quantified type variable `n' escapes Expected type: (v (L m, L n) - w) - t Inferred type: (forall n1 m1. (ReflectNum n1, ReflectNum m1) = v (L m1, L n1) - w) - w In the first argument of `print', namely `m2' In the result of a 'do' expression: print m2 I would also like to create a matrix from a data file: main = do let m1 = $(dAM [[1,2],[3,4::Double]]) s - readFile data.txt let list = read s :: [[Double]] --let m2 = $(dAM list) let m2 = listMat list print $ m2 * trans m1 But I get a similar error. Perhaps I must provide information about the expected dimensions, but I don't know how to do it. -- Alberto On Saturday 15 April 2006 22:09, Frederik Eaton wrote: Yes, certainly... Otherwise the library would not be much use! If it seems counterintuitive, as it did to me at first, you should check out the Implicit Configurations paper, which uses modular arithmetic as an example. My version of their code is in http://ofb.net/~frederik/futility/src/Prepose.hs The function I mainly use is: reifyIntegral :: Integral a = a - (forall s. ReflectNum s = s - w) - w which turns an integral value into a type of the ReflectNum class which represents that value, and calls the provided polymorphic function with a dummy value (actually 'undefined') of that type; then returning the function's result. Frederik On Sat, Apr 15, 2006 at 06:14:44PM +0200, Alberto Ruiz wrote: On Friday 14 April 2006 17:02, Frederik Eaton wrote: An index-aware linear algebra library in Haskell Excellent work! Is it possible to create a vector or matrix whose size is not known at compile time? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Code Review: Sudoku solver
I have added 'solve method F', aka X-wing, swordfish... (www.sudokusolver.co.uk) to my solver, that reduced the number of puzzles needing guesses to 5306, so I suppose that's it. I haven't yet implemented it efficiently, so it was devastating for performance - and solving thirteen puzzles more by pure logic (or should we rather say without using any assumptions except that the puzzle is solvable, uniquely or not?) isn't such a big step, I had hoped for more. Cheers, Daniel Am Freitag, 14. April 2006 21:40 schrieb Chris Kuklewicz: I believe if you change the representation of puzzles from [(pos,range)] to an Array, you'll get a significant speedup yet because I only recently removed a logic bug that slowed down the search instead of speading it up; ..). so the more interesting bit is that our solvers disagree on which are the most difficult puzzles (requiring the largest number of guesses): df puzzles involving guesses: 5319 If that's not a typo, I'm baffled. My original needed to guess in 5309 Rot! Typo in _my_ previous message, 5319 is correct. After posting my cleaned up dancing links solver, I went back to my logical solver. I sent the 36628 line sudoku17 puzzle through it and it could solve 31322 of the puzzles, leaving 5306 resistant. I haven't check my algorithms against your code, but it does not seem like I do any spectacularly more clever. I don't have any time to clean up my code, but I may try turning off some steps to see if one of them gives my the same 5319 number you are seeing. -- In My Egotistical Opinion, most people's C programs should be indented six feet downward and covered with dirt. -- Blair P. Houghton ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: [Haskell] ANNOUNCE: An index-aware linear algebra library in Haskell
Hi Alberto, Those are good questions, I've added some examples which hopefully clarify the situation. Input and output of vectors is not a strong point of the library, but I don't think there is a good alternative to the way I do it. http://ofb.net/~frederik/futility/src/Vector/read-example.hs (also, your example exposed some missing functionality. I've added three new functions; in addition to listMat, now there are listMatCol, listMatRow, and listMatSquare. Hopefully these should cover almost all use cases. http://ofb.net/~frederik/futility/src/Vector/Base.hs ) By the way, here is how I would download and run the thing, although you seem to have figured it out: $ wget http://ofb.net/~frederik/futility/futility-devel.tar.gz $ tar -xvzf futility-devel.tar.gz $ cd futility-devel/ $ ghc -fth --make Vector/read-example.hs -o read-example $ ./read-example # 11.0, 23.0; 14.0, 30.0; 15.0, 33.0; 18.0, 40.0 # 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 # 1.0, 5.0; 2.0, 6.0; 3.0, 6.0; 4.0, 7.0 # # 11.0, 23.0; 14.0, 30.0; 15.0, 33.0; 18.0, 40.0 # # -3.0, -5.0; -5.0, -7.0 # # 7.0, 10.0; 15.0, 22.0 # As for your questions: Vector/examples.hs:35:11: GHC stage restriction: `x' is used in a top-level splice, and must be imported, not defined locally In the first argument of `dAM', namely `x' In the definition of `m1': m1 = $[splice](dAM x) This is a shortcoming of Template Haskell - it will not let you call a function from a splice if that function is defined in the same file as the splice. It should be possible to remove this shortcoming, but I don't know what is planned. m2 = listMat x This is not how listMat is used, see the example file above. listMat takes a list of lists and a function, and passes the matrix version of the list of lists to the function. I would also like to create a matrix from a data file: See 'v3' in the example. Cheers, Frederik On Sun, Apr 16, 2006 at 05:06:55PM +0200, Alberto Ruiz wrote: It is really counterintuitive! I will study carefully your library and the Implicit Configurations paper. Using static dimension checking we can write very solid code for matrix computations... However, I don't know how to write some definitions. For instance, this is ok: m = $(dAM [[1,2,3]]) but with: x = [[1,2,3]] :: [[Double]] m1 = $(dAM x) m2 = listMat x main = do print m1 print m2 I get: Vector/examples.hs:35:11: GHC stage restriction: `x' is used in a top-level splice, and must be imported, not defined locally In the first argument of `dAM', namely `x' In the definition of `m1': m1 = $[splice](dAM x) Vector/examples.hs:40:10: Inferred type is less polymorphic than expected Quantified type variable `m' escapes Quantified type variable `n' escapes Expected type: (v (L m, L n) - w) - t Inferred type: (forall n1 m1. (ReflectNum n1, ReflectNum m1) = v (L m1, L n1) - w) - w In the first argument of `print', namely `m2' In the result of a 'do' expression: print m2 I would also like to create a matrix from a data file: main = do let m1 = $(dAM [[1,2],[3,4::Double]]) s - readFile data.txt let list = read s :: [[Double]] --let m2 = $(dAM list) let m2 = listMat list print $ m2 * trans m1 But I get a similar error. Perhaps I must provide information about the expected dimensions, but I don't know how to do it. -- Alberto On Saturday 15 April 2006 22:09, Frederik Eaton wrote: Yes, certainly... Otherwise the library would not be much use! If it seems counterintuitive, as it did to me at first, you should check out the Implicit Configurations paper, which uses modular arithmetic as an example. My version of their code is in http://ofb.net/~frederik/futility/src/Prepose.hs The function I mainly use is: reifyIntegral :: Integral a = a - (forall s. ReflectNum s = s - w) - w which turns an integral value into a type of the ReflectNum class which represents that value, and calls the provided polymorphic function with a dummy value (actually 'undefined') of that type; then returning the function's result. Frederik On Sat, Apr 15, 2006 at 06:14:44PM +0200, Alberto Ruiz wrote: On Friday 14 April 2006 17:02, Frederik Eaton wrote: An index-aware linear algebra library in Haskell Excellent work! Is it possible to create a vector or matrix whose size is not known at compile time? -- http://ofb.net/~frederik/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Re: coherence when overlapping?
Coherence may also arise because of an ambiguous type.
Here's the classic example.
class Read a where read :: String - a
class Show a where show :: a - String
f s = show (read s)
f has type String-String, therefore we can pick
some arbitrary Read/Show classes.
If you want to know more about coherence/ambiguity in the Haskell context.
Check out
@TechReport{jones:coherence,
author = M. P. Jones,
title =Coherence for qualified types,
institution = Yale University, Department of Computer Science,
year = 1993,
month = September,
type = Research Report,
number = YALEU/DCS/RR-989
}
and
@Article{overloading-journal,
author = {P.~J.~Stuckey and M.~Sulzmann },
title ={A Theory of Overloading},
journal = {ACM Transactions on Programming Languages and Systems
(TOPLAS)},
publisher = ACM Press,
year = 2005,
pages = 1-54,
volume = 27,
number = 6,
preprint =
{http://www.comp.nus.edu.sg/~sulzmann/chr/download/theory-journal.ps.gz}}
As far as I know, the term coherence was coined by
@article{breazu-tannen-etal:inhertiance-coercion,
author = V. Breazu{-}Tannen and T. Coquand and C. Gunter
and A. Scedrov,
title = Inheritance as Implicit Coercion,
journal = Information and Computation,
volume = 93,
number = 1,
month = jul,
year =1991,
pages = 172--221
}
Martin
william kim writes:
Thank you Martin.
Coherence (roughly) means that the program's semantics is independent
of the program's typing.
In case of your example below, I could type the program
either use the first or the second instance (assuming
g has type Int-Int). That's clearly bound.
If g has type Int-Int, it is not hard to say the first instance should
apply.
But how about g having a polymorphic type? In this case it seems to me
choosing the second instance is an acceptable choice as that is the only
applicable one at the moment. What is the definition of a coherent
behaviour here? Or is there one?
Non-overlapping instances are necessary but not sufficient to
obtain coherence. We also need that types/programs are unambiguous.
Do you therefore imply that coherence is not defined without the
non-overlapping assumption?
--william
_
Get MSN Hotmail alerts on your mobile.
http://mobile.msn.com/ac.aspx?cid=uuhp_hotmail
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
