Re: [Haskell-cafe] Ideas on a fast and tidy CSV library
Dear All, I now have some example code. I have put it on: http://pastebin.com/D9MPmyVd. vectorBinner is simply of type Vector Int - Int. I am inputting a 1.5GB CSV on stdin, and would like vectorBinner to run over every single record, outputting results as computed, thus running in constant memory. My programme instead quickly approaches full memory use. Is there any way to work around this? Justin On 25 July 2013 17:53, Johan Tibell johan.tib...@gmail.com wrote: You can use the Incremental or Streaming modules to get more fine grained control over when new parsed records are produced. On Thu, Jul 25, 2013 at 11:02 AM, Justin Paston-Cooper paston.coo...@gmail.com wrote: I hadn't yet tried profiling the programme. I actually deleted it a few days ago. I'm going to try to get something new running, and I will report back. On a slightly less related track: Is there any way to use cassava so that I can have pure state and also yield CSV lines while my computation is running instead of everything at the end as would be with the State monad? On 23 July 2013 22:13, Johan Tibell johan.tib...@gmail.com wrote: On Tue, Jul 23, 2013 at 5:45 PM, Ben Gamari bgamari.f...@gmail.com wrote: Justin Paston-Cooper paston.coo...@gmail.com writes: Dear All, Recently I have been doing a lot of CSV processing. I initially tried to use the Data.Csv (cassava) library provided on Hackage, but I found this to still be too slow for my needs. In the meantime I have reverted to hacking something together in C, but I have been left wondering whether a tidy solution might be possible to implement in Haskell. Have you tried profiling your cassava implementation? In my experience I've found it's quite quick. If you have an example of a slow path I'm sure Johan (cc'd) would like to know about it. I'm always interested in examples of code that is not running fast enough. Send me a reproducible example (preferably as a bug on the GitHub bug tracker) and I'll take a look. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Ideas on a fast and tidy CSV library
I hadn't yet tried profiling the programme. I actually deleted it a few days ago. I'm going to try to get something new running, and I will report back. On a slightly less related track: Is there any way to use cassava so that I can have pure state and also yield CSV lines while my computation is running instead of everything at the end as would be with the State monad? On 23 July 2013 22:13, Johan Tibell johan.tib...@gmail.com wrote: On Tue, Jul 23, 2013 at 5:45 PM, Ben Gamari bgamari.f...@gmail.com wrote: Justin Paston-Cooper paston.coo...@gmail.com writes: Dear All, Recently I have been doing a lot of CSV processing. I initially tried to use the Data.Csv (cassava) library provided on Hackage, but I found this to still be too slow for my needs. In the meantime I have reverted to hacking something together in C, but I have been left wondering whether a tidy solution might be possible to implement in Haskell. Have you tried profiling your cassava implementation? In my experience I've found it's quite quick. If you have an example of a slow path I'm sure Johan (cc'd) would like to know about it. I'm always interested in examples of code that is not running fast enough. Send me a reproducible example (preferably as a bug on the GitHub bug tracker) and I'll take a look. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Ideas on a fast and tidy CSV library
Dear All, Recently I have been doing a lot of CSV processing. I initially tried to use the Data.Csv (cassava) library provided on Hackage, but I found this to still be too slow for my needs. In the meantime I have reverted to hacking something together in C, but I have been left wondering whether a tidy solution might be possible to implement in Haskell. I would like to build a library that satisfies the following: 1) Run a function f :: a_1 - ... - a_n - m (Maybe (b_1, ..., b_n)), with m some monad and the as and bs being input and output. 2) Be able to specify a maximum record string length and output record string length, so that the string buffers used for reading and outputting lines can be reused, preventing the need for allocating new strings for each record. 3) Allocate only once, the memory where the parsed input values, and output values are put. 4) The library's main function should take some kind of data structure describing the types of the function, the function itself and the filenames of input and output (could also be stdin/stdout). I am not sure yet what would be that best value of m. I would like to most importantly efficiently, and if possible, purely allow changes in state to a number of variables, such as an aggregation over a certain field in the input. I do not currently have knowledge of the FFI, and how it might be used in this case. I would appreciate any suggestions as to where I should look further. Regards, Justin Paston-Cooper ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Solving integer equations in Haskell
Thanks for all the informative replies. SBV seems the simplest solution right now, and speed isn't too much of an issue here. Anything under 20 seconds per solution should be bearable. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Solving integer equations in Haskell
Hello, Can anyone suggest a library written in Haskell which can solve equations of the form xM(transpose(x)) = y, where x should be an integer vector, M is an integer matrix and y is an integer? I'm aware that Mathematica can do this, but I would like something written in Haskell. I haven't been sure of what exact keywords I should be searching for, hence my asking here. Thanks, Justin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
