Re: [Haskell] Haskell 6.4 perfomance
Keean, thank you. Does any tests/benchmarks available? Regards, /Alexandre. On Mar 25, 2005, at 00:47, Keean Schupke wrote: Think this should really go to glasgow-haskell-users... If this is true - how do I get ghc to use C--, and is it really faster than using gcc as a backend with all the bells whistles turned on (for a pentium-III) something like -O3 -mcpu=pentium3 -march=pentium3 -pipe -fomit-frame-pointer -momit-leaf-frame-pointer -ftracer -fno-crossjumping -mfpmath=sse,387 -ffast-math -fsched-spec-load -fprefetch-loop-arrays -maccumulate-outgoing-args -fmove-all-movables -freduce-all-givs Keean. Alexandre wrote: As I heard, 6.4 version of the Haskell using C-- backend and make lots of the resulting code perfomance (programs executed faster). If so, does any test/comparison with other languages available? Thank you in advance, Regards, /Alexandre. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Allowing duplicate instances in GHC 6.4
Hi all, I need to use duplicate instances. I read in the documentation on GHC 6.4, that overlapping class instances checks are lazy instead of gready in 6.4. However, my code still gives duplicate instance errors when compiling in GHC 6.4. Is the duplicate instance check still gready? Is there a way to overwrite that behaviour? Right now, I have two instance of a class Datasource. Datasource allows the user to read (key,value) pairs. class Datasource ds k v where ... Now, I wanted to make a special datasource that combines two datasources, namely data JoinedDS left right = JoinedDS left right instance (Datasource left k v) = Datasource (JoinedDS left right) k v where ... instance (Datasource right k v) = Datasource (JoinedDS left right) k v where ... The idea is that when you combine 2 datasources in one JoinedDS, the user can read both types from the JoinedDS. I do not need to allow to combine 2 different datasources that have the same types of (key,value) pairs, so the duplicate instances will not occur and when they do, this will be by mistake. Hence, the two premisses in the instance declaration will never be fulfilled both at the same time and I do not want a duplicate instance error here. Is there a solution to this problem? Thanks, Robert ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Biographical Profiling
Hallo! The ghc user guide says that there are 4 states a heap object may be in. Unfortunately in my program there are 5 states (inherent_use, use, drag, lag, void) with inherent_use being the biggest part (many MBs) and the one not mentioned in the users guide. My question is what does it mean? What can I do to get rid of it? Thanks, Andreas ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Robert van Herk wrote: Hi all, I need to use duplicate instances. I read in the documentation on GHC 6.4, that overlapping class instances checks are lazy instead of gready in 6.4. However, my code still gives duplicate instance errors when compiling in GHC 6.4. Is the duplicate instance check still gready? Is there a way to overwrite that behaviour? Right now, I have two instance of a class Datasource. Datasource allows the user to read (key,value) pairs. class Datasource ds k v where ... Now, I wanted to make a special datasource that combines two datasources, namely data JoinedDS left right = JoinedDS left right instance (Datasource left k v) = Datasource (JoinedDS left right) k v where ... instance (Datasource right k v) = Datasource (JoinedDS left right) k v where ... The idea is that when you combine 2 datasources in one JoinedDS, the user can read both types from the JoinedDS. I do not need to allow to combine 2 different datasources that have the same types of (key,value) pairs, so the duplicate instances will not occur and when they do, this will be by mistake. Hence, the two premisses in the instance declaration will never be fulfilled both at the same time and I do not want a duplicate instance error here. Is there a solution to this problem? To resolve overlap the HEAD of the instance must be different... Might I suggest: -- as value depends on source and key, requires functional dependancy class Datasource s k v | s k - v ... data JoinedDS l r = JoinedDS l r instance (Datasource l k v1,Datasource r k v2) = Datasource (JoinedDS l r) k (v1,v2) ... Now a joined datasource resturns a pair of values instead of a single value. Keean. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Keean Schupke wrote: Robert van Herk wrote: Hi all, I need to use duplicate instances. I read in the documentation on GHC 6.4, that overlapping class instances checks are lazy instead of gready in 6.4. However, my code still gives duplicate instance errors when compiling in GHC 6.4. Is the duplicate instance check still gready? Is there a way to overwrite that behaviour? Right now, I have two instance of a class Datasource. Datasource allows the user to read (key,value) pairs. class Datasource ds k v where ... Now, I wanted to make a special datasource that combines two datasources, namely data JoinedDS left right = JoinedDS left right instance (Datasource left k v) = Datasource (JoinedDS left right) k v where ... instance (Datasource right k v) = Datasource (JoinedDS left right) k v where ... The idea is that when you combine 2 datasources in one JoinedDS, the user can read both types from the JoinedDS. I do not need to allow to combine 2 different datasources that have the same types of (key,value) pairs, so the duplicate instances will not occur and when they do, this will be by mistake. Hence, the two premisses in the instance declaration will never be fulfilled both at the same time and I do not want a duplicate instance error here. Is there a solution to this problem? To resolve overlap the HEAD of the instance must be different... Might I suggest: -- as value depends on source and key, requires functional dependancy class Datasource s k v | s k - v ... data JoinedDS l r = JoinedDS l r instance (Datasource l k v1,Datasource r k v2) = Datasource (JoinedDS l r) k (v1,v2) ... Now a joined datasource resturns a pair of values instead of a single value. Further to this to get the exact behaviour you want, if a datasource can return the result using a type lifted maybe on a lookup failure then: class Datasource s k v | s k - v ... data JoinedDS l r = JoinedDS l r instance (Datasource l k v1, Datasource r k v2, JoinDS v1 v2 v) = Datasource (JoinedDS l r) k v class Fail data This_should_never_happen data TNothing = TNothing data TJust a = TJust a class JoinDS l r t | l r - t instance JoinDS TNothing TNothing TNothing instance JoinDS TNothing (TJust v) (TJust v) instance JoinDS (TJust u) TNothing (TJust u) instance Fail This_should_never_happen = JoinDS (TJust u) (TJust v) TNothing Now you datasources just need to return the type TJust v on success and TNothing on failure. Keean. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Keean Schupke wrote: Robert van Herk wrote: Hi all, I need to use duplicate instances. I read in the documentation on GHC 6.4, that overlapping class instances checks are lazy instead of gready in 6.4. However, my code still gives duplicate instance errors when compiling in GHC 6.4. Is the duplicate instance check still gready? Is there a way to overwrite that behaviour? Right now, I have two instance of a class Datasource. Datasource allows the user to read (key,value) pairs. class Datasource ds k v where ... Now, I wanted to make a special datasource that combines two datasources, namely data JoinedDS left right = JoinedDS left right instance (Datasource left k v) = Datasource (JoinedDS left right) k v where ... instance (Datasource right k v) = Datasource (JoinedDS left right) k v where ... The idea is that when you combine 2 datasources in one JoinedDS, the user can read both types from the JoinedDS. I do not need to allow to combine 2 different datasources that have the same types of (key,value) pairs, so the duplicate instances will not occur and when they do, this will be by mistake. Hence, the two premisses in the instance declaration will never be fulfilled both at the same time and I do not want a duplicate instance error here. Is there a solution to this problem? To resolve overlap the HEAD of the instance must be different... Might I suggest: -- as value depends on source and key, requires functional dependancy class Datasource s k v | s k - v ... Yes, I already had that, forgot to mention it though... data JoinedDS l r = JoinedDS l r instance (Datasource l k v1,Datasource r k v2) = Datasource (JoinedDS l r) k (v1,v2) ... Now a joined datasource resturns a pair of values instead of a single value. Yes, but this is not what I want. I want to be able to give a key that either the left or the right data source would take, and then return the appropriate value. Thus: if I pass it a key that would normally go into l, I want the value l returns me to be returned, and if I pass it the key that would normally go into r, I want to return the value r returns me. The datasource class has a function dsread :: ds - k - (ds, v) -- read may have a side effect Thus I want want to do something like: instance (Datasource l k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (l, v) = dsread l k in (JoinedDS l r, v) instance (Datasource r k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (r, v) = dsread r k in (JoinedDS l r, v) It would be perfectly okay to me when the compiler would complain if the key and value that go into l and r are the same, but for any useful purpose I can think of (e.g. glueing two database couplings together, since I also made a Datasource instance for database access), this will not happen and the duplicate instances should not really occur, since the context of the instances makes sure only 1 will be possible. However, GHC only looks at the RHS (thus: Datasource (JoinedDS l r) k v) and then decides that both instances are the same. So, my question was: how to overcome this. Thanks, Robert ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
There was a typo in the code I posted: class Fail data This_should_never_happen should read: class Fail x data This_should_never_happen Keean. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Just thought I ought to point out that all this is only necessary if the datasources may return different types... If you want them to return the same type you only need: instance (Datasource l k v,Datasource r k v) = Datasource (JoinedDS l r) k v ... As both datasources have the same key and value types, you then choose which 'v' to return at the value level. I am not sure whether you intended Datasources to contain heterogeneous key or value types, and whether the loolup is supposed to be value or type driven. My original answer assumed a single Datasource contains values of different types, selected by the type of the key... Keean. Robert van Herk wrote: Yes, but this is not what I want. I want to be able to give a key that either the left or the right data source would take, and then return the appropriate value. Thus: if I pass it a key that would normally go into l, I want the value l returns me to be returned, and if I pass it the key that would normally go into r, I want to return the value r returns me. The datasource class has a function dsread :: ds - k - (ds, v) -- read may have a side effect Thus I want want to do something like: instance (Datasource l k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (l, v) = dsread l k in (JoinedDS l r, v) instance (Datasource r k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (r, v) = dsread r k in (JoinedDS l r, v) It would be perfectly okay to me when the compiler would complain if the key and value that go into l and r are the same, but for any useful purpose I can think of (e.g. glueing two database couplings together, since I also made a Datasource instance for database access), this will not happen and the duplicate instances should not really occur, since the context of the instances makes sure only 1 will be possible. However, GHC only looks at the RHS (thus: Datasource (JoinedDS l r) k v) and then decides that both instances are the same. So, my question was: how to overcome this. Thanks, Robert ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Keean Schupke wrote: Just thought I ought to point out that all this is only necessary if the datasources may return different types... If you want them to return the same type you only need: instance (Datasource l k v,Datasource r k v) = Datasource (JoinedDS l r) k v ... As both datasources have the same key and value types, you then choose which 'v' to return at the value level. Nono, the datasources I have implemented are a type safe means to extract (key,value) pairs from a data store. The idea is that this way, in a type safe fashion, e.g. database access can be abstract. I use HaskellDB as the database access layer, and then define a datasource instance for any given database, so that the user does not need to think about the details of the actual database access: he can just read and write from the datasource, and the datasource will make sure the actual queries will be executed. My idea now was that if I have 2 databases, and I construct datasources for them, it would be really cool if I was able to unite them, so that the programmer in the end could talk two 1 datasource, that allowed for accessing the 2 databases at one entry point. This was what I was making the JoinedDS for. So, suppose I have 2 datasources for two different databases. One may have keys: data KeysOfDS1 = KDB1_Table1 Int | KDB1_Table2 Int and values data ValuesOfDS1 = VDB1_Table1 (Int,Int,String) | VDB2_Table2 (Int,Int,String) and the other one: data KeysOfDS2 = KDB2_Table1 String | KDB2_Table2 String data ValuesOfDS2 = VDB2_Table1 (String, Float) | VDB2_Table2 (String, Float, Int) Now, these datastructures correspond to the actual tables in the database. My toolset will generate datasources for these types, thus we have instances: instance Datasource Database1 KeysOfDS1 ValuesOfDS1 instance Datasource Database2 KeysOfDS2 ValuesOfDS2 and the cool thing would be, to combine these two datasources at a higher level in my datasources graph, so that I would have 1 datasource that found out by itself which actual datasource to use, thus: x::JoinedDS x = JoinedDS db1 db2 -- where dbx is a datasource Databasex KeysOfDSx ValuesOfDSx Now, I would want the user to be able to read both KeysOfDS1 (which would yield a ValuesOfDS1) as well as KeysOfDS2 (which would yield a ValuesOfDS2) from x. Herefore, I need the instances mentioned before: instance (Datasource l k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (l, v) = dsread l k in (JoinedDS l r, v) instance (Datasource r k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (r, v) = dsread r k in (JoinedDS l r, v) But this, thus, yields duplicate instance errors, which I don't like :-). Robert P.S. Sorry for any typos, I am enjoying a rather nice bottle of wine :-). I am not sure whether you intended Datasources to contain heterogeneous key or value types, and whether the loolup is supposed to be value or type driven. My original answer assumed a single Datasource contains values of different types, selected by the type of the key... Keean. Robert van Herk wrote: Yes, but this is not what I want. I want to be able to give a key that either the left or the right data source would take, and then return the appropriate value. Thus: if I pass it a key that would normally go into l, I want the value l returns me to be returned, and if I pass it the key that would normally go into r, I want to return the value r returns me. The datasource class has a function dsread :: ds - k - (ds, v) -- read may have a side effect Thus I want want to do something like: instance (Datasource l k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (l, v) = dsread l k in (JoinedDS l r, v) instance (Datasource r k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (r, v) = dsread r k in (JoinedDS l r, v) It would be perfectly okay to me when the compiler would complain if the key and value that go into l and r are the same, but for any useful purpose I can think of (e.g. glueing two database couplings together, since I also made a Datasource instance for database access), this will not happen and the duplicate instances should not really occur, since the context of the instances makes sure only 1 will be possible. However, GHC only looks at the RHS (thus: Datasource (JoinedDS l r) k v) and then decides that both instances are the same. So, my question was: how to overcome this. Thanks, Robert ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Allowing duplicate instances in GHC 6.4
Robert van Herk wrote: Keean Schupke wrote: Just thought I ought to point out that all this is only necessary if the datasources may return different types... If you want them to return the same type you only need: instance (Datasource l k v,Datasource r k v) = Datasource (JoinedDS l r) k v ... As both datasources have the same key and value types, you then choose which 'v' to return at the value level. Nono, the datasources I have implemented are a type safe means to extract (key,value) pairs from a data store. The idea is that this way, in a type safe fashion, e.g. database access can be abstract. I use HaskellDB as the database access layer, and then define a datasource instance for any given database, so that the user does not need to think about the details of the actual database access: he can just read and write from the datasource, and the datasource will make sure the actual queries will be executed. My idea now was that if I have 2 databases, and I construct datasources for them, it would be really cool if I was able to unite them, so that the programmer in the end could talk two 1 datasource, that allowed for accessing the 2 databases at one entry point. This was what I was making the JoinedDS for. So, suppose I have 2 datasources for two different databases. One may have keys: data KeysOfDS1 = KDB1_Table1 Int | KDB1_Table2 Int and values data ValuesOfDS1 = VDB1_Table1 (Int,Int,String) | VDB2_Table2 (Int,Int,String) and the other one: data KeysOfDS2 = KDB2_Table1 String | KDB2_Table2 String data ValuesOfDS2 = VDB2_Table1 (String, Float) | VDB2_Table2 (String, Float, Int) Now, these datastructures correspond to the actual tables in the database. My toolset will generate datasources for these types, thus we have instances: instance Datasource Database1 KeysOfDS1 ValuesOfDS1 instance Datasource Database2 KeysOfDS2 ValuesOfDS2 and the cool thing would be, to combine these two datasources at a higher level in my datasources graph, so that I would have 1 datasource that found out by itself which actual datasource to use, thus: x::JoinedDS x = JoinedDS db1 db2 -- where dbx is a datasource Databasex KeysOfDSx ValuesOfDSx Now, I would want the user to be able to read both KeysOfDS1 (which would yield a ValuesOfDS1) as well as KeysOfDS2 (which would yield a ValuesOfDS2) from x. Herefore, I need the instances mentioned before: instance (Datasource l k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (l, v) = dsread l k in (JoinedDS l r, v) instance (Datasource r k v) = Datasource (JoinedDS l r) k v where dsread (JoinedDS l r) k = let (r, v) = dsread r k in (JoinedDS l r, v) But this, thus, yields duplicate instance errors, which I don't like :-). Robert P.S. Sorry for any typos, I am enjoying a rather nice bottle of wine :-). Thats because they overlap in 'k'. However you can change the fundep: class Datasource s k v | s - k v instance Datasource DB1 K1 V1 instance Datasource DB2 K2 V2 instance (Datasource l k' v',TypeEq k k' z,Datasource' z l r k v) = Datasource (JoinedDS l r) k v where class Datasource' z l r k v | z l r - k v instance Datasource l k v = Datasource' TTrue l r k v instance Datasource r k v = Datasource' TFalse l r k v Here I have used TypeEq from the HList library to determine if the type parameter k is the same type as the k' from datasource l. This lets k determine which instance from the other class gets used. Keean. ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: [Haskell] The FunctorM library
Simon Peyton-Jones wrote: | | class Functor f where fmap :: ... | class Functor m = Monad m where | ...the usual stuff... | fmap = liftM | It seems overkill to have a whole new language feature to deal with one library issue. Perhaps it is... For example, what if Functor T *is* defined explicitly, but in a later module? I guess it would be the same as what happens now if you accidentally declare the same instance in different modules, i.e., the system would complain about overlapping instances. -- Thomas H ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Profiling strategies
Hallo! Does anybody have some profiling strategies other than from the ghc user guide? Any references, suggestions and so on are very welcome. Thanks, Andreas ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell-cafe] Question on leazy evaluation
Still on the same subject, I solved one problem but don't really understand why it didn't work in the first place ! Although it seems to be a difference between newtype and data ! I have a newtype defined as : data Fct s a = Fct (s - [a]) and a function defined by : plus :: Fct a b - Fct a b - Fct a b plus (Fct f1) (Fct f2) = Fct ( \ a - (f1 a) ++ (f2 a) ) For some reason, this function does not use leazy evaluation ! I can test it using : test_fct :: Fct Int Int test_fct = Fct( \ i - [i] ) value = head $ apply (foldr plus test_fct $ repeat test_fct) 12 ... trying to get value does not terminate ! But if I change the type declaration into : newtype Fct s a = Fct (s - [a]) ... it works ! The plus function uses leazy evaluation and value can be computed. Now, I didn't really understood the difference between newtype and data. Can anyone explain that behaviour ? Thank you, Pierre -- Pierre Barbier de Reuille INRA - UMR Cirad/Inra/Cnrs/Univ.MontpellierII AMAP Botanique et Bio-informatique de l'Architecture des Plantes TA40/PSII, Boulevard de la Lironde 34398 MONTPELLIER CEDEX 5, France tel : (33) 4 67 61 65 77fax : (33) 4 67 61 56 68 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Question on leazy evaluation
On Fri, Mar 25, 2005 at 03:13:48PM +0100, Pierre Barbier de Reuille wrote: plus :: Fct a b - Fct a b - Fct a b plus (Fct f1) (Fct f2) = Fct ( \ a - (f1 a) ++ (f2 a) ) For some reason, this function does not use leazy evaluation ! I can test it using : test_fct :: Fct Int Int test_fct = Fct( \ i - [i] ) value = head $ apply (foldr plus test_fct $ repeat test_fct) 12 ... trying to get value does not terminate ! That's because you pattern match on (Fct f2) in plus. If Fct is defined with 'data', this causes the second argument of plus to be evaluated. But if I change the type declaration into : newtype Fct s a = Fct (s - [a]) ... it works ! The plus function uses leazy evaluation and value can be computed. If Fct is defined with 'newtype', it doesn't cause evaluation, because Fct is a kind of virtual / non-existent / zero-cost data constructor, so there is nothing to evaluate. Try these definitions: plus (Fct f1) ~(Fct f2) = Fct ( \ a - (f1 a) ++ (f2 a) ) plus (Fct f1) f2 = Fct ( \ a - (f1 a) ++ (apply f2 a) ) The first uses an irrefutable pattern, the second doesn't pattern match on Fct in the second argument. Best regards Tomasz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
