Re: complex numbers in clojure
I have been thinking along the lines of mikera and Maik - and it seems like
there is no further progress here? I would like to take a crack at creating
a complex number type, but implemented as a library to Clojure. I am not
sure where to start, and if anyone here has suggestions, I'd be happy to
hear them.
A complex number could simply be a vector of two elements, or a map with
:real and :imag keys (or something lightweight) - and I am not sure what it
would require to make this type work happily with code arithmetic functions
in Clojure and Java Math.
It would also have to work with seq operations in Clojure - for instance:
If I have a complex number c = {:real 3 :imag 4}, and a vector v = [1 -2
c], it would be nice to have the call 'map #(Math/abs %) v' produce (1 2
5).
I am having trouble figuring out all the pieces that need to be
implemented. Is it even possible to implement this as a library, or does
this need to be a part of clojure.core?
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Re: complex numbers in clojure
This is what I suspected. Of course, this is not just for abs, but really
for any mathematical operation. Sqrt, Trig operations etc.
I will study the Ratio type more closely, but note that something like
(Math/abs (/ 22 7)) does not work.
On Monday, April 27, 2015 at 12:45:32 PM UTC-4, Gary Verhaegen wrote:
As far as I understand, your example with Math/abs would need to be part
of Java.
You cannot extend the arithmetic operators in Java, and you will not be
able to extend static Java methods like Math/abs.
What you may be able to do is make your custom type play nice with Clojure
operators, like Clojure's rationals and bignums.
I'd suggest looking at the code for these, and considering a Java class
with two primitive attributes rather than a Clojure vector or map (which
have a big overhead compared to a simple number). Depending on what you
want to do, you may also want to consider implementing a vector of
complex type, which could be a single object with two primitive arrays.
If you're targeting a performant implementation, you should probably cross
post to numerical-clojure; people over there have a lot of experience about
numerical optimizations in Clojure.
On Monday, 27 April 2015, endbegin nkri...@gmail.com javascript:
wrote:
I have been thinking along the lines of mikera and Maik - and it seems
like there is no further progress here? I would like to take a crack at
creating a complex number type, but implemented as a library to Clojure. I
am not sure where to start, and if anyone here has suggestions, I'd be
happy to hear them.
A complex number could simply be a vector of two elements, or a map with
:real and :imag keys (or something lightweight) - and I am not sure what it
would require to make this type work happily with code arithmetic functions
in Clojure and Java Math.
It would also have to work with seq operations in Clojure - for instance:
If I have a complex number c = {:real 3 :imag 4}, and a vector v = [1 -2
c], it would be nice to have the call 'map #(Math/abs %) v' produce (1 2
5).
I am having trouble figuring out all the pieces that need to be
implemented. Is it even possible to implement this as a library, or does
this need to be a part of clojure.core?
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Re: complex numbers in clojure
As far as I know, Java Math does not have a complex number type. Some
implementations of a complex number exist (such as Apache Commons Math),
but they create a Complex class that implements Serializeable and a Commons
specific interface.
Modifying clojure.core itself is a bit daunting, and like you said, it
would need to be a priority for the core team.
On Monday, April 27, 2015 at 12:45:46 PM UTC-4, Andy Fingerhut wrote:
Unless the Java Math library handles complex types already, I don't know
of any way to extend it in a way that would let you get the answer you want
from (Math/abs my-complex-number) in Clojure.
If you want code that gives the correct answers, a library using vectors
or maps for complex numbers can get you there. Memory footprint and
performance should be better with Clojure records or a new class written
directly in Java. With a library, I don't know of any way to be able to
mix Clojure's arithmetic operations like + - * / etc. with its existing
numeric types, and your new library-implemented complex types.
Support of Clojure's arithmetic operations on complex numbers might only
be achievable by modifying Clojure itself. Depending upon your goals, the
down side of that approach is that it will not become part of the normal
Clojure distribution unless the Clojure core team wants that addition,
which I would guess would be very low on their priority list (just a guess
-- I have no inside knowledge there).
Andy
On Mon, Apr 27, 2015 at 8:39 AM, endbegin nkri...@gmail.com javascript:
wrote:
I have been thinking along the lines of mikera and Maik - and it seems
like there is no further progress here? I would like to take a crack at
creating a complex number type, but implemented as a library to Clojure. I
am not sure where to start, and if anyone here has suggestions, I'd be
happy to hear them.
A complex number could simply be a vector of two elements, or a map with
:real and :imag keys (or something lightweight) - and I am not sure what it
would require to make this type work happily with code arithmetic functions
in Clojure and Java Math.
It would also have to work with seq operations in Clojure - for instance:
If I have a complex number c = {:real 3 :imag 4}, and a vector v = [1 -2
c], it would be nice to have the call 'map #(Math/abs %) v' produce (1 2
5).
I am having trouble figuring out all the pieces that need to be
implemented. Is it even possible to implement this as a library, or does
this need to be a part of clojure.core?
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Re: IllegalArgumentException when running core.async example
Thanks!! That did it. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
IllegalArgumentException when running core.async example
Hi I was trying to teach myself core.async and tried the rock, paper, scissors example found here: http://tech.puredanger.com/2013/07/10/rps-core-async/ See a gist here: https://gist.github.com/endbegin/b10be6d7a3ba5f6c29db Really, the main difference is in the :require statement at the top, and whenever I use a function from the core.async library, I prepend it with async. For instance, async/go or async/! and so on. I am using CIDER + Emacs, and Clojure 1.5.1, core.async 0.1.303.0-886421-alpha. I created a new app with Lein, and when I do a CTRL+C+k, the file compiles just fine. However, when I try to play the game, I do a (def game (init)) (play game) and get the error: IllegalArgumentException No implementation of method: :take! of protocol: #'clojure.core.async.impl.protocols/ReadPort found for class: clojure.core.async$chan clojure.core/-cache-protocol-fn (core_deftype.clj:541) *What does this mean?!?* *P.S.* If I replace the :require at the top with (:require [clojure.core.async :refer :all])) I can't even get it to compile. I get an error about there being a conflict between the partition-by in clojure.core and in core.async. Thanks for the help! -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: IllegalArgumentException when running core.async example
Just tried it with Clojure 1.6.0. Still no luck! -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: can Clojure 1.3 code always be made as fast as Java for numeric computations?
On Tuesday, March 27, 2012 2:51:41 PM UTC-4, Jay Fields wrote: I recently ran into some code** that was in Java, and ran in single digit microseconds (not millis). I converted it to clojure, and got it running at about the same speed... though it did take me a day to figure out all the tweaks. It can be done, if you're willing to invest the time and learn the tricks. Cheers, Jay That is good to know. Is there a place where the tricks involved were documented? As in, here is what you should think about to get Java-like performance. I've seen fragments in different places, and a lot of them applied to Clojure 1.2 or earlier. Based on what I have seen on Stack Overflow, it seems like if you want Java performance, then you have dig down into direct Java interop, and use things like Java arrays. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: How to add a new type of collection?
I know this isn't exactly what the OP is looking for, but the Incanter project has done something for dense matrices that might work. The Matrix type has been imported (which is a java class), and a whole bunch of functions have been implemented on that class. See here https://github.com/liebke/incanter/blob/master/modules/incanter-core/src/incanter/core.clj -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
extracting the execution time of a function ...
Hi, I am new to learning clojure, and I am hoping there is a solution to something that is not obvious to me ... I have a function that I want to run multiple times, measure the time it takes to execute each function, and put those numbers in a vector. I would like to process that vector further by doing things like max, min and average, and I think I can do that fairly easily, but I'm having trouble generating such a vector in the first place. For instance when I do this: = (dorun (repeatedly 3 myfunc)) I get Elapsed time: 1253.764 msecs Elapsed time: 20003.997 msecs Elapsed time: 653.919 msecs nil I would like to get something like [1253.764 23.997 653.919], which I can post-process. I tried a = (conj [] (dorun (repeatedly 3 myfunc))) but that just gives me a [nil]. Can anyone help? Thanks ... -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: extracting the execution time of a function ...
Thanks Cedric. I did something along the lines of what you suggested (created a function instead of a macro). Here's what I did to get time in seconds: (defn run-myfunc [] (let [starttime (System/nanoTime)] (myfunc) (/ (- (System/nanoTime) starttime) 1e9))) and then to produce timings across 10 runs, (vec (repeatedly 10 run-myfunc)) produces the desired vector. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
