Thanks Daniel,
I see. So I need to use "=" for numerical comparisons. "equal?" is only true if
the types are the same, too:
(equal? 1.0 1)
; #f
(= 1.0 1)
; #t
Sorry for filing a bug report. Feel free to close the bug.
Regards
Jan
On November 22, 2017 3:53:00 PM GMT, Daniel Llorens <daniel.llor...@bluewin.ch>
wrote:
>
>> From: Jan Wedekind <j...@wedesoft.de>
>> Subject: bug#29387: Guile-2.2.2 complex numbers edge case
>> Date: 21 Nov 2017 23:09:57 GMT+1
>> To: 29...@debbugs.gnu.org
>> Reply-To: Jan Wedekind <j...@wedesoft.de>
>>
>>
>> Hi,
>> I think I encountered a bug in the numerical stack.
>> i times i should equal -1:
>>
>> (equal? -1 (* 0+i 0+i))
>> ; #f
>>
>> i times i plus one is zero (which is correct):
>> (zero? (+ (* 0+i 0+i) 1))
>> ; #t
>>
>> Regards
>> Jan
>
>In Guile 0+i and (* 0+i 0+i) are inexact numbers, but -1 is exact.
>That's why equal? fails.
>
>You can check that either of
>
>(equal? -1.+0. (* 0+i 0+i))
>
>or
>
> (= -1 (* 0+i 0+i))
>
>return true, as expected.
>
>I don't know if the fact that Guile doesn't have exact complex numbers
>could be considered a bug. AFAIR none of the standards require them to
>be implemented. On the other hand I just checked and both Racket and
>Chez seem to have them, so...
>
>regards
>
> Daniel
