- Glasgow-haskell-users

Re: Fundeps and type equality
by Iavor Diatchki 11 Jan '13

11 Jan '13

Hello Conal, GHC implementation of functional dependencies is incomplete: it will use functional dependencies during type inference (i.e., to determine the values of free type variables), but it will not use them in proofs, which is what is needed in examples like the one you posted. The reason some proving is needed is that the compiler needs to figure out that for each instantiation of the type `ta` and `tb` will be the same (which, of course, follows directly from the FD on the class). As far as I understand, the reason that GHC does not construct such proofs is that it can't express them in its internal proof language (System FC). It seems to me that it should be fairly straight-forward to extend FC to support this sort of proof, but I have not been able to convince folks that this is the case. I could elaborate, if there's interest. In the mean time, the way forward would probably be to express the dependency using type families, which I find tends to be more verbose but, at present, is better supported in GHC. Cheers, -Iavor PS: cc-ing the GHC users' list, as there was some talk of closing the ghc-bugs list, but I am not sure if the transition happened yet. On Tue, Dec 25, 2012 at 6:15 PM, Conal Elliott <conal(a)conal.net> wrote: > I ran into a simple falure with functional dependencies (in GHC 7.4.1): > > > class Foo a ta | a -> ta > > > > foo :: (Foo a ta, Foo a tb, Eq ta) => ta -> tb -> Bool > > foo = (==) > > I expected that the `a -> ta` functional dependency would suffice to prove > that `ta ~ tb`, but > > Pixie/Bug1.hs:9:7: > Could not deduce (ta ~ tb) > from the context (Foo a ta, Foo a tb, Eq ta) > bound by the type signature for > foo :: (Foo a ta, Foo a tb, Eq ta) => ta -> tb -> Bool > at Pixie/Bug1.hs:9:1-10 > `ta' is a rigid type variable bound by > the type signature for > foo :: (Foo a ta, Foo a tb, Eq ta) => ta -> tb -> Bool > at Pixie/Bug1.hs:9:1 > `tb' is a rigid type variable bound by > the type signature for > foo :: (Foo a ta, Foo a tb, Eq ta) => ta -> tb -> Bool > at Pixie/Bug1.hs:9:1 > Expected type: ta -> tb -> Bool > Actual type: ta -> ta -> Bool > In the expression: (==) > In an equation for `foo': foo = (==) > Failed, modules loaded: none. > > Any insights about what's going wrong here? > > -- Conal > > _______________________________________________ > Glasgow-haskell-bugs mailing list > Glasgow-haskell-bugs(a)haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs > >

9 20

(mips64el) Cross-building GHC
by jugree＠lavabit.com 11 Jan '13

11 Jan '13

Hello. I would like to port GHC to mips64el. I have never tried cross-building before. So I will probably post more questions later. Actually, I am not sure that I am using the right term. I am going to use my i686 machine to build GHC for mips64el. In terms of this page(0): B = i686-unknown-linux H = mips64el-unknown-linux T = mips64el-unknown-linux Is the above correct? What I did: 1. Downloaded this(1) tarball (on i686) and unpacked it. 2. Executed the following commands(2): ghc-7.6.1$ cp /bin/pwd utils/ghc-pwd/ghc-pwd ghc-7.6.1$ perl boot ghc-7.6.1$ ./configure --enable-hc-boot --build=i686-unknown-linux --host=mips64el-unknown-linux --target=mips64el-unknown-linux Output: checking for gfind... no checking for find... /usr/bin/find checking for sort... /usr/bin/sort checking for ghc... /usr/bin/ghc checking version of ghc... 6.12.1 checking build system type... i686-unknown-linux-gnu checking host system type... mips64el-unknown-linux-gnu checking target system type... mips64el-unknown-linux-gnu HOST: mips64el-unknown-linux-gnu GHC build : i386-unknown-linux GHC host : mips-unknown-linux GHC target : mips-unknown-linux configure: Building in-tree ghc-pwd ghc: unrecognised flags: -no-user- Usage: For basic information, try the `--help' option. configure: error: Building ghc-pwd failed /ghc-7.6.1$ grep "no-user" ./* ./aclocal.m4: if ! "$WithGhc" -v0 -no-user-$GHC_PACKAGE_DB_FLAG -hidir utils/ghc-pwd/dist-boot -odir utils/ghc-pwd/dist-boot -stubdir utils/ghc-pwd/dist-boot --make utils/ghc-pwd/Main.hs -o utils/ghc-pwd/dist-boot/ghc-pwd ./configure: if ! "$WithGhc" -v0 -no-user-$GHC_PACKAGE_DB_FLAG -hidir utils/ghc-pwd/dist-boot -odir utils/ghc-pwd/dist-boot -stubdir utils/ghc-pwd/dist-boot --make utils/ghc-pwd/Main.hs -o utils/ghc-pwd/dist-boot/ghc-pwd How can I fix this? I can't find any information about this option. Thank you. PS: I only use free software (as defined by the FSF). Can I be sure that I won't install any non-free programs during the process? (0) http://hackage.haskell.org/trac/ghc/wiki/CrossCompilation (1) http://www.haskell.org/ghc/dist/7.6.1/ghc-7.6.1-src.tar.bz2 (2) http://hackage.haskell.org/trac/ghc/wiki/Building/Porting

3 4

missing mtl (which exists) when installing filemanip package
by HP Wei 10 Jan '13

10 Jan '13

I did the following: download filemanip-0.3.6.2.tar.gz tar xvf ... cd filemanip-0.3.6.2 runhaskell Setup configure --prefix=$HOME/ghc --> it tells me Setup: At least the following dependencies are missing: mtl -any, unix-compat -any So, I did the following: download unix-compat-0.4.1.0.tar.gz tar xvf ... cd unix-compat-0.4.1.0 runhaskell Setup configure --prefix=$HOME/ghc runhaskell Setup build runhaskell Setup install --> under $HOME/ghc/lib I see unix-compat-0.4.1.0/ that was newly added by the Setup processes. --> under $HOME/ghc/lib I also see mtl-2.0.1.0/ This was there already before the above operations. Then, I went back cd filemanip-0.3.6.2 runhaskell Setup configure --prefix=$HOME/ghc --> it tells me Setup: At least the following dependencies are missing: mtl -any Question: why can't $HOME/ghc/lib/mtl-2.0.1.0/ be recognized during the above Setup configure ?? What do I need to do ? thanks HP

3 2

Suppress "Duplicate constraints" warning?
by Conal Elliott 03 Jan '13

03 Jan '13

Is there a way to suppress GHC's "Duplicate constraints" warning? I'm auto-generating some code, and it's a lot more convenient for me to leave the duplicates than filter them out. -- Conal

3 5

Error building ghc on raspberry pi.
by roconnor＠theorem.ca 03 Jan '13

03 Jan '13

I'm trying to build ghc-7.4.1 using ghc-7.4.1 on my raspberry pi (armv6l) and I get the following error: "inplace/bin/ghc-stage1" -H32m -O -package-name ghc-prim-0.2.0.0 -hide-all-packages -i -ilibraries/ghc-prim/. -ilibraries/ghc-prim/dist-install/build -ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/dist-install/build -Ilibraries/ghc-prim/dist-install/build/autogen -Ilibraries/ghc-prim/. -optP-include -optPlibraries/ghc-prim/dist-install/build/autogen/cabal_macros.h -package rts-1.0 -package-name ghc-prim -XHaskell98 -XCPP -XMagicHash -XForeignFunctionInterface -XUnliftedFFITypes -XUnboxedTuples -XEmptyDataDecls -XNoImplicitPrelude -O2 -no-user-package-conf -rtsopts -odir libraries/ghc-prim/dist-install/build -hidir libraries/ghc-prim/dist-install/build -stubdir libraries/ghc-prim/dist-install/build -hisuf hi -osuf o -hcsuf hc -c libraries/ghc-prim/./GHC/Types.hs -o libraries/ghc-prim/dist-install/build/GHC/Types.o Stack dump: 0. Program arguments: llc -O3 -relocation-model=static /tmp/ghc6324_0/ghc6324_0.bc -o /tmp/ghc6324_0/ghc6324_0.lm_s 1. Running pass 'Function Pass Manager' on module '/tmp/ghc6324_0/ghc6324_0.bc'. 2. Running pass 'ARM Instruction Selection' on function '@ghczmprim_GHCziTypes_Czh_info' /tmp/ghc6324_0/ghc6324_0.lm_s: openBinaryFile: does not exist (No such file or directory) make[1]: *** [libraries/ghc-prim/dist-install/build/GHC/Types.o] Error 1 make: *** [all] Error 2 Anyone have any thoughts on what might be the matter and what I can do to fix it. (If only openBinaryFile said which file doesn't exist.) -- Russell O'Connor <http://r6.ca/> ``All talk about `theft,''' the general counsel of the American Graphophone Company wrote, ``is the merest claptrap, for there exists no property in ideas musical, literary or artistic, except as defined by statute.''

3 4

Re: DoCon and GHC
by Serge D. Mechveliani 03 Jan '13

03 Jan '13

On Wed, Jan 02, 2013 at 05:21:43PM +0000, Simon Peyton-Jones wrote: > Serge > > That's odd. I've tried with both 7.6 and HEAD, and both fail on T_cubeext > thus: > T_cubeext.hs:102:10: > Overlapping instances for LinSolvRing (UPol k) > arising from a use of `upEucRing' > Matching instances: > instance [overlap ok] EuclideanRing a => LinSolvRing (UPol a) > -- Defined in `docon-2.12:Pol2_' > instance [overlap ok] (LinSolvRing (Pol a), CommutativeRing a) => > LinSolvRing (UPol (Pol a)) > -- Defined in `docon-2.12:Pol3_' > (The choice depends on the instantiation of `k' > To pick the first instance above, use -XIncoherentInstances > when compiling the other instance declarations) > In the expression: upEucRing unA Map.empty > In an equation for `dA': dA = upEucRing unA Map.empty > > I am using ghc-7.6 from Dec 3 (ie *later* than the released GHC 7.6.1), > so perhaps the difference in error message is due to a bug in 7.6.1 that's > fixed in my version. I suggest you use the 7.6.2 release candidate. Yes, the candidate of 7.6.1.20121207 > Anyway, the error message looks entirely legitimate. It really does > matter how 'k' is instantiated! I have no idea how it compiled before. ghc-7.4.1 compiles everything in DoCon, and it is the last such version. > The solution is to add (EuclideanRing k) to the type sig of cubicExt. > Then it compiles all the way up to the top. But the DoCon declares class (EuclideanRing a, FactorizationRing a) => Field a (EuclideanRing is a superclass for Field), and the test declares cubicExt :: (Field k, FactorizationRing (UPol k)) => k -> k -> Domains1 k -> (Domains1 (E k), [E k], k -> E k) So, why the compiler does not `extract' EuclideanRing k from Field k ? Regards, ------ Sergei > | -----Original Message----- > | From: glasgow-haskell-bugs-bounces(a)haskell.org [mailto:glasgow-haskell- > | bugs-bounces(a)haskell.org] On Behalf Of Serge D. Mechveliani > | Sent: 21 December 2012 18:46 > | To: Simon Peyton-Jones > | Cc: glasgow-haskell-bugs(a)haskell.org > | Subject: Re: DoCon and GHC > | > | On Fri, Dec 21, 2012 at 01:45:04PM +0000, Simon Peyton-Jones wrote: > | > OK, do this > | > > | > * {-# LANGUAGE ScopedTypeVariables, MonoLocalBinds #-} > | > > | > * import Categs( Domains1 ) > | > > | > * Add type sig for dP' > | > dP' :: (LinSolvRing (Pol a), CommutativeRing a) => Domains1 (Pol > | > a) > | > > | > Then it compiles. > | > > | > You are very close to the edge of what can be done! > | > | > | It works. Thank you. > | > | There remains only a single unlucky module: T_cubeext. > | The test demotest/Main works with exception of T_cubeext, but I need > | T_cubeext.cubicExt to work. > | > | Please, continue the test with > | > | make install > | cd demotest > | ghc $doconCpOpt --make Main > | > | (for $doconCpOpt = > | -fwarn-unused-matches -fwarn-unused-binds -fwarn-unused-imports > | -fno-warn-overlapping-patterns -XRecordWildCards -XNamedFieldPuns > | -XFlexibleContexts -XMultiParamTypeClasses -XUndecidableInstances > | -XTypeSynonymInstances -XFlexibleInstances -XOverlappingInstances ). > | > | It reports > | > | ------------------------------------------------------------------ > | ... > | T_cubeext.hs:102:20: > | Could not deduce (k ~ k1) > | from the context (Field k, FactorizationRing (UPol k)) > | bound by the type signature for > | cubicExt :: (Field k, FactorizationRing (UPol k)) => > | k -> k -> Domains1 k -> (Domains1 (E k), [E > | k], k -> E k) > | at T_cubeext.hs:(79,13)-(80,69) > | or from (Field k1, FactorizationRing (UPol k1)) > | bound by the type signature for > | unA :: (Field k1, FactorizationRing (UPol k1)) => UPol > | k1 > | at T_cubeext.hs:101:9-56 > | `k' is a rigid type variable bound by > | the type signature for > | cubicExt :: (Field k, FactorizationRing (UPol k)) => > | k -> k -> Domains1 k -> (Domains1 (E k), [E k], > | k -> E k) > | at T_cubeext.hs:79:13 > | `k1' is a rigid type variable bound by > | the type signature for > | unA :: (Field k1, FactorizationRing (UPol k1)) => UPol k1 > | at T_cubeext.hs:101:9 > | Expected type: Domains1 k1 > | Actual type: Domains1 k > | In the second argument of `cToUPol', namely `dK' > | In the expression: cToUPol "d" dK unK > | In an equation for `unA': unA = cToUPol "d" dK unK > | > | T_cubeext.hs:105:7: > | Overlapping instances for LinSolvRing (UPol k1) > | arising from a use of `upEucRing' > | Matching instances: > | instance [overlap ok] EuclideanRing a => LinSolvRing (UPol a) > | -- Defined in `docon-2.12:Pol2_' > | instance [overlap ok] (LinSolvRing (Pol a), CommutativeRing a) => > | LinSolvRing (UPol (Pol a)) ... > | ------------------------------------------------------------------ > | > | I tried {-# LANGUAGE ScopedTypeVariables, MonoLocalBinds #-}, and > | setting type signatures in various parts in cubicExt. > | But this does not help. > | > | There is another point. In > | ``cubicExt :: (Field k, FactorizationRing (UPol k)) => ...'' > | > | the part ``, FactorizationRing (UPol k)'' (1) > | > | was always considered as parasitic. ghc-7.4.1 needs (1) to work, and > | at least ghc-7.4.1 does compile the test. > | > | I thought, may be, the future compilers will allow to omit this part. > | At least it is desirable for ghc-7.6.2 to do the test in any variant, > | with (1) or without it.

3 7

Re: ANNOUNCE: GHC 7.6.2 Release Candidate 1
by Christian Maeder 03 Jan '13

03 Jan '13

worked for me under x86 SunOS 5.10 Cheers Christian OVERALL SUMMARY for test run started at Donnerstag, 3. Januar 2013, 09:52:19 Uhr CET 3402 total tests, which gave rise to 13556 test cases, of which 10 caused framework failures 10486 were skipped 2954 expected passes 47 had missing libraries 36 expected failures 0 unexpected passes 33 unexpected failures Unexpected failures: ../../libraries/base/tests/IO openFile003 [bad stdout] (normal) ../../libraries/process/tests 3994 [bad exit code] (threaded1) ../../libraries/process/tests process007 [bad stdout] (normal) ../../libraries/unix/tests 3816 [bad exit code] (normal) ../../libraries/unix/tests user001 [bad stdout] (normal) ../../libraries/unix/tests/libposix posix002 [bad exit code] (normal) ../../libraries/unix/tests/libposix posix005 [bad stdout] (normal) cabal/cabal01 cabal01 [bad exit code] (normal) cabal/cabal03 cabal03 [bad exit code] (normal) cabal/cabal04 cabal04 [bad exit code] (normal) lib/integer IntegerConversionRules [bad stderr] (normal) lib/integer T7041 [bad stderr] (normal) lib/integer integerConstantFolding [bad exit code] (normal) perf/haddock haddock.Cabal [stat too good] (normal) perf/haddock haddock.base [stat too good] (normal) perf/haddock haddock.compiler [stat too good] (normal) plugins plugins01 [bad exit code] (normal) plugins plugins02 [stderr mismatch] (normal) plugins plugins03 [stderr mismatch] (normal) rts exec_signals [bad exit code] (normal) safeHaskell/check/pkg01 ImpSafeOnly01 [exit code non-0] (normal) safeHaskell/check/pkg01 ImpSafeOnly02 [exit code non-0] (normal) safeHaskell/check/pkg01 ImpSafeOnly03 [stderr mismatch] (normal) safeHaskell/check/pkg01 ImpSafeOnly04 [exit code non-0] (normal) safeHaskell/check/pkg01 ImpSafeOnly05 [stderr mismatch] (normal) safeHaskell/check/pkg01 ImpSafeOnly06 [exit code non-0] (normal) safeHaskell/check/pkg01 ImpSafeOnly07 [stderr mismatch] (normal) safeHaskell/check/pkg01 ImpSafeOnly08 [stderr mismatch] (normal) safeHaskell/check/pkg01 ImpSafeOnly09 [stderr mismatch] (normal) safeHaskell/check/pkg01 ImpSafeOnly10 [exit code non-0] (normal) safeHaskell/check/pkg01 safePkg01 [bad exit code] (normal) simplCore/should_compile T5658b [bad exit code] (normal) simplCore/should_compile T5776 [bad exit code] (normal) On 09/12/12 21:39, Ian Lynagh wrote: > > We are pleased to announce the first release candidate for GHC 7.6.2: > > http://www.haskell.org/ghc/dist/7.6.2-rc1/ > > This includes the source tarball, installers for Windows, and > bindists for Windows, Linux, OS X and FreeBSD, on x86 and x86_64. > > We plan to make the 7.6.2 release early in 2013. > > Please test as much as possible; bugs are much cheaper if we find them > before the release!

1 0

Re: Error building ghc on raspberry pi.
by Thijs Alkemade 03 Jan '13

03 Jan '13

(Sorry, forgot to CC the list) -------- Original Message -------- From: Thijs Alkemade <me(a)thijsalkema.de> Sent: Thu Jan 03 10:31:50 CET 2013 To: roconnor(a)theorem.ca Subject: Re: Error building ghc on raspberry pi. roconnor(a)theorem.ca wrote: >Some further information it seems that llc is segfaulting: > >pi@raspberrypi /tmp/ghc-7.4.1 $ llc -O3 -relocation-model=static >/tmp/ghc7189_0/ghc7189_0.bc -o /tmp/ghc7189_0/ghc7189_0.lm_s >Stack dump: >0. Program arguments: llc -O3 -relocation-model=static >/tmp/ghc7189_0/ghc7189_0.bc -o /tmp/ghc7189_0/ghc7189_0.lm_s >1. Running pass 'Function Pass Manager' on module >'/tmp/ghc7189_0/ghc7189_0.bc'. >2. Running pass 'ARM Instruction Selection' on function >'@ghczmprim_GHCziTypes_Czh_info' >Segmentation fault >pi@raspberrypi /tmp/ghc-7.4.1 $ llc --version >Low Level Virtual Machine (http://llvm.org/) > llvm version 3.0 > (Debian 3.0-10)Optimized build. > Built Jul 26 2012 (20:20:52). > Host: arm-unknown-linux-gnueabihf > Host CPU: (unknown) > > Registered Targets: > alpha - Alpha [experimental] > arm - ARM > bfin - Analog Devices Blackfin [experimental] > c - C backend > cellspu - STI CBEA Cell SPU [experimental] > cpp - C++ backend > mblaze - MBlaze > mips - Mips > mips64 - Mips64 [experimental] > mips64el - Mips64el [experimental] > mipsel - Mipsel > msp430 - MSP430 [experimental] > ppc32 - PowerPC 32 > ppc64 - PowerPC 64 > ptx32 - PTX (32-bit) [Experimental] > ptx64 - PTX (64-bit) [Experimental] > sparc - Sparc > sparcv9 - Sparc V9 > systemz - SystemZ > thumb - Thumb > x86 - 32-bit X86: Pentium-Pro and above > x86-64 - 64-bit X86: EM64T and AMD64 > xcore - XCore > >On Wed, 2 Jan 2013, roconnor(a)theorem.ca wrote: > >> I'm trying to build ghc-7.4.1 using ghc-7.4.1 on my raspberry pi >(armv6l) and >> I get the following error: >> >> "inplace/bin/ghc-stage1" -H32m -O -package-name ghc-prim-0.2.0.0 > >> -hide-all-packages -i -ilibraries/ghc-prim/. >> -ilibraries/ghc-prim/dist-install/build >> -ilibraries/ghc-prim/dist-install/build/autogen >> -Ilibraries/ghc-prim/dist-install/build >> -Ilibraries/ghc-prim/dist-install/build/autogen >-Ilibraries/ghc-prim/. >> -optP-include >> -optPlibraries/ghc-prim/dist-install/build/autogen/cabal_macros.h >-package >> rts-1.0 -package-name ghc-prim -XHaskell98 -XCPP -XMagicHash >> -XForeignFunctionInterface -XUnliftedFFITypes -XUnboxedTuples >> -XEmptyDataDecls -XNoImplicitPrelude -O2 -no-user-package-conf >-rtsopts >> -odir libraries/ghc-prim/dist-install/build -hidir >> libraries/ghc-prim/dist-install/build -stubdir >> libraries/ghc-prim/dist-install/build -hisuf hi -osuf o -hcsuf hc -c > >> libraries/ghc-prim/./GHC/Types.hs -o >> libraries/ghc-prim/dist-install/build/GHC/Types.o >> Stack dump: >> 0. Program arguments: llc -O3 -relocation-model=static >> /tmp/ghc6324_0/ghc6324_0.bc -o /tmp/ghc6324_0/ghc6324_0.lm_s 1. >Running >> pass 'Function Pass Manager' on module '/tmp/ghc6324_0/ghc6324_0.bc'. >> 2. Running pass 'ARM Instruction Selection' on function >> '@ghczmprim_GHCziTypes_Czh_info' >> /tmp/ghc6324_0/ghc6324_0.lm_s: openBinaryFile: does not exist (No >such file >> or directory) >> make[1]: *** [libraries/ghc-prim/dist-install/build/GHC/Types.o] >Error 1 >> make: *** [all] Error 2 >> >> Anyone have any thoughts on what might be the matter and what I can >do to fix >> it. (If only openBinaryFile said which file doesn't exist.) >> >> I believe I had the same problem, which disappeared after upgrading llvm from 3.0 to 3.1, and using that instead for ./configure. Hope this helps, Thijs

1 0

Re: [Haskell-cafe] [Haskell-beginners] ghc and android
by Bernhard Urban 02 Jan '13

02 Jan '13

On Tue, Jan 1, 2013 at 1:13 PM, Ivan Perez <ivanperezdominguez(a)gmail.com> wrote: > Please, let us know if you manage to compile it. There are some comments regarding porting git-annex to android, in order to make it useable from shell (that is, not as android app). http://git-annex.branchable.com/design/assistant/android/ The main issue: The GHC runtime relies on glibc, which is not used on android. Also, glibc cannot be (fully) linked statically. Probably someone with more knowledge about GHC internals and glibc can came up with a clean solution to this problem. > An additional issue: ghci (and Template Haskell because it uses the > bytecode interpreter of ghci internally) currently(?) requires its own > custom linker instead of being able to use the system linker. Said linker > has no support for ARM. The correct fix for this is to redesign ghci so it > doesn't need its own linker; there has been some work in this direction, > but I don't know how complete it is, and it interacts with other issues > such as building Haskell libraries as shared objects. http://www.haskell.org/pipermail/glasgow-haskell-users/2012-December/023163… I don't know the situation on ARM though. I added ghc-users mailinglist to CC. Regards, Bernhard

3 3

Is there a workaround for this bug?
by Dominic Steinitz 01 Jan '13

01 Jan '13

AFAICT this bug fix http://hackage.haskell.org/trac/ghc/ticket/7239 did not make it into 7.6.1. Also I am happily working on the Haskell Platform with 7.4.1 and I'd rather avoid upgrading if possible. Is there a workaround? I've attached my code below along with the error message (which is the same as in the above bug report). I'm rather hoping I won't have to build HEAD. Thanks, Dominic. bash-3.2$ ghc -fext-core --make Test.hs [1 of 1] Compiling Main ( Test.hs, Test.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.4.1 for x86_64-apple-darwin): MkExternalCore died: make_lit {-# LANGUAGE FlexibleContexts #-} {-# OPTIONS_GHC -Wall -fno-warn-name-shadowing -fno-warn-type-defaults #-} import Data.Array.Repa as Repa import Data.Array.Repa.Eval import Control.Monad r, sigma, k, t, xMax, deltaX, deltaT :: Double m, n :: Int r = 0.05 sigma = 0.2 k = 50.0 t = 3.0 m = 80 xMax = 150 deltaX = xMax / (fromIntegral m) n = 800 deltaT = t / (fromIntegral n) data PointedArrayU a = PointedArrayU Int (Array U DIM1 a) deriving Show f :: PointedArrayU Double -> Double f (PointedArrayU j _x) | j == 0 = 0.0 f (PointedArrayU j _x) | j == m = xMax - k f (PointedArrayU j x) = a * x! (Z :. j-1) + b * x! (Z :. j) + c * x! (Z :. j+1) where a = deltaT * (sigma^2 * (fromIntegral j)^2 - r * (fromIntegral j)) / 2 b = 1 - deltaT * (r + sigma^2 * (fromIntegral j)^2) c = deltaT * (sigma^2 * (fromIntegral j)^2 + r * (fromIntegral j)) / 2 priceAtT :: PointedArrayU Double priceAtT = PointedArrayU 0 (fromListUnboxed (Z :. m+1) [ max 0 (deltaX * (fromIntegral j) - k) | j <- [0..m] ]) coBindU :: (Source U a, Source U b, Target U b, Monad m) => PointedArrayU a -> (PointedArrayU a -> b) -> m (PointedArrayU b) coBindU (PointedArrayU i a) f = computeP newArr >>= return . PointedArrayU i where newArr = traverse a id g where g _get (Z :. j) = f $ PointedArrayU j a testN :: Int -> IO (PointedArrayU Double) testN n = h priceAtT where h = foldr (>=>) return (take n $ Prelude.zipWith flip (repeat coBindU) (repeat f)) main :: IO () main = do r <- testN n putStrLn $ show r

3 3