2009/8/13 <[email protected]>: > For the mathematical part yes. Now, submiting to all the list, I want to > propose a modification in the code based on Smalltalk style (the comments > w/"csr" are only for my explanation and should not go to the production > code!): > > < other > "Can only compare with pure real or imaginary parts" > ((self imaginary = 0) and: [other imaginary = 0]) > ifTrue: [^ self real < other real]. "csr: if it's true you
i think, if imaginary part is zero , then Complex values should be normalized back to real ones (obviously to conserve the memory), and therefore the test 'self imaginary = 0' is redundant. > returned, so no need the iFalse part" > ((self real = 0) and: [other real = 0]) > ifTrue: [^self imaginary < other imaginary]. "csr: same here" > ArithmeticError new signal: 'Complex numbers are not generally comparable' > "csr: Only will happen if no one of the above blocks returned" > But back to the question: in given form, i really don't see what is the meaning of #< operator on Complex numbers? Because , obviously, in first place, i expecting that #< method serves to compare Complex numbers, not mix of real and complex, but implemented in such form, the value of such method is nearly zero (in complex plane ;). So, the question remains the same: is it worth adding it, just for the sake of complete protocol(s)? P.S. diving into complex plane uncovers many potential pitfalls to those who expecting a certain behavior of mathematical functions over a real numbers. In first place square and square root. It is good that with introduction of a complex numbers we can be sure that x sqrt squared = x for any real x. The complex numbers gives us a impression that from now on, the square function and squared root functions is reversable. But they are not for a complex numbers. In practice this means, that one, who using a complex math in his code, should know well the properties of complex numbers, because this is not so trivial as with real numbers & school algebra. And such people, basically don't need the things with questionable or controversial behavior such as #< operators on a complex plane. Then the aim of Complex package developer should be to not introduce more confusion to people who is not using/learnt the complex numbers, and leave attempts to help people who can - because they could care for themselves well. > HTH > > Em 12/08/2009 21:39, Ken.Dickey < [email protected] > escreveu: > > OK, here is a strict version. Complex>>< only compares numbers on the real > or > imaginal axis and throws an "incomparable" error otherwise. The > ComplexTest>>textCompare checks obvious cases. > > Is this version (more) acceptable? > > As usual, please feel free to correct (or send me corrections) for better > coding style (e.g a shorter/better error message) as well as any dumbness on > my part. > > Cheers, > -KenD > ------------------------Complex > < other > "Can only compare with pure real or imaginary parts" > ((self imaginary = 0) and: [other imaginary = 0]) > ifTrue: [^ self real < other real] > ifFalse: [((self real = 0) and: [other real = 0]) > ifTrue: [^self imaginary < other imaginary] > ifFalse: [ArithmeticError new > signal: 'Complex numbers are not generally co mparable'.] > ] > ------------------------ > > > > _______________________________________________ > Pharo-project mailing list > [email protected] > http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project > -- Best regards, Igor Stasenko AKA sig. _______________________________________________ Pharo-project mailing list [email protected] http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
