Well, I don't find the question to be irrelevant. It makes me think about a couple issues:
1.) Should Complex and Imaginary extend java.lang.Number? 2.) What do we do with the standard Java math functions? 3.) Is 'i' by itself, valid input as a number? First, I do not propose that just "i" or "j" is enough to indicate the imaginary number, no more than just 'd' means the number 1.0d (the latter is correct way to write a double in Java and in clojure). That said, I would expect the same result that clojure gives now: user=> (Math/pow (Math/E (* 2/5 2 Math/PI i))) java.lang.Exception: Unable to resolve symbol: i in this context (NO_SOURCE_FILE:4) If you use: 1.0i user=> (Math/pow (Math/E (* 2/5 2 Math/PI 1.0i))) java.lang.IllegalArgumentException: No matching method: E (NO_SOURCE_FILE:1) Oops! You have an extra set of parenthesis! If you meant (Math/pow Math/E (* 2/5 2 Math/PI 1.0i)), then the answer depends on whether Imaginary extends Number. If it does logical (but perhaps confusing) answer is: user=> (Math/pow (Math/E (* 2/5 2 Math/PI 1.0i)) 1.0 Why? Because you're forcing java.lang.Math.pow(double, double). Java will then force the cast of the Imaginary number to a double by calling doubleValue() on "2.51327412i" which has no real component, thus, you're finding E^0.0 = 1.0. This is the exact same behavior you would have in Java if you were working with a custom Complex Java type which extends Number. If, however, we choose the route Commons Math chooses (to not extend Number), we should get something like we get now if we pass a non- Number type to Math/pow: user=> (Math/pow Math/E "cat") java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Number (NO_SOURCE_FILE:0) So, I would expect something like: user=> (Math/pow Math/E 5i) java.lang.ClassCastException: clojure.lang.Imaginary cannot be cast to a java.lang.Number (NO_SOURCE_FILE:0) To get something useful, one would have to use a library (a standard clojure math library) which supports the complex type, just as it is in Java. This seems to be the preferable approach. Thanks for the skepticism and the question! -Travis On Jun 8, 11:03 am, Mike Meyer <mwm-keyword-googlegroups. 620...@mired.org> wrote: > On Tue, 8 Jun 2010 10:27:28 -0700 (PDT) > > Steven Devijver <steven.devij...@gmail.com> wrote: > > On 8 jun, 16:38, Mike Meyer <mwm-keyword-googlegroups. > > 620...@mired.org> wrote: > > > > Why? It isn't supported for rationals or exponents. Or are you > > > claiming that because we support "3/4" we should also support > > > > (* (my-complicated-algo val)/(my-other-complicated-algo exp) > > > 1/(another-complicated-algo exp2)) > > > > with similar problems because we support "1e3"? > > > What would (Math/pow (Math/E (* 2/5 2 Math/PI i))) return? > > Why is this relevant to a discussion of whether or not support for > complex literals is desirable? All but "i" is involved with the > semantics of complex values, not the literal. > > <mike > -- > Mike Meyer <m...@mired.org> http://www.mired.org/consulting.html > Independent Network/Unix/Perforce consultant, email for more information. > > O< ascii ribbon campaign - stop html mail -www.asciiribbon.org -- 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
