On Mar 27, 2012 6:26 PM, "Andrea Chiavazza" <ndrch...@gmail.com> wrote:
>
> Hello everyone
>
> I had a go at adding support for complex numbers, it's at:
> https://github.com/andrea-chiavazza/clojure/tree/complex
>
> Some repl usage examples:
>
> user=> (/ (complex 73 13) (complex 15 25))
> #<Complex (142/85 -163/85i)>
>
> user=> (/ (complex 73 13) (complex 15.0 25.0))
> #<Complex (1.6705882352941177 -1.9176470588235295i)>
>
> user=> (+ (complex 13 34) (complex 29 -34))
> 42
>
> user=> (require 'clojure.math)
>
> user=> (clojure.math/abs (complex -14.94 21))
> 25.772147756832375
>
> user=> (clojure.math/sqrt -3)
> #<Complex (0 +1.7320508075688772i)>
>
> user=> (clojure.math/sqrt 2)
> 1.4142135623730951
>
> user=> (clojure.math/sqrt (complex 2 3))
> #<Complex (1.6741492280355401 +0.895977476129838i)>
>
> user=> (= (complex 12 34) (complex 12 34.0))
> false
> user=> (== (complex 12 34) (complex 12 34.0))
> true
>
> I'm still not sure why #<Complex comes up, while #<Ratio doesn't with
similar operations.
You need to define a custom print-method for Complex.
> What also worries me a bit is that I changed a bunch of methods in
Numbers.java from accepting Object to being overloaded to accept Number and
Complex.
My intuition here is that the "public interface" of Numbers.java always
operates on Objects (essentially data with an unknown type at compile
time). The methods in Numbers.java that take more specific types are for
the compiler's use when optimizing, via inlining, type hinting, and
intrinsics.
> For example, this:
> static public Number add(Object x, Object y){
> return ops(x).combine(ops(y)).add((Number)x, (Number)y);
> }
>
> Has become:
> static public Number add(Number x, Number y){
> return ops(x).combine(ops(y)).add(x, y);
> }
>
> So that I could overload with this:
> static public Object add(Complex x, Complex y) {
> Number r = add(x.real, y.real);
> Number im = add(x.imaginary, y.imaginary);
> if (isZero(im))
> return r;
> else
> return new Complex(r, im);
> }
>
> A consequence is that this test:
> (is (thrown? ClassCastException (+ "ab" "cd"))) ) ; no string
concatenation
> Has become:
> (is (thrown? IllegalArgumentException (+ "ab" "cd"))) ) ; no string
concatenation
>
> I thought that overloading would be nicer and would avoid having to check
for the class of the Object.
> On the other hand all methods seem to accept an Object and then cast to
Number rather than just accepting a Number, so there might be a good reason
for that.
> Could somebody please enlighten me on this so that I can do it the right
way ?
>
> --
> 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 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
