Being a bit nasty...  ;-)

Why do you say it is broken?
Modulo an error bound of 10^(-15) it looks OK.

Do you expect exact values when you compute with floating point numbers?

Ralf

(7) -> a := (-1.0 :: Complex(Float))^(0.5)

   (7)  0.2022266248_7959507324 E -20 + %i
                                   Type: Complex(Float)
(8) -> b := (-1.0 :: Complex(DoubleFloat))^(0.5)

   (8)  6.123233995736766e-17 - %i
                                   Type: Complex(DoubleFloat)
(9) -> a^2

   (9)  - 1.0 + 0.4044532497_5919014648 E -20 %i
                                    Type: Complex(Float)
(10) -> b^2

   (10)  - 1.0 - 1.2246467991473532e-16 %i
                                    Type: Complex(DoubleFloat)


On 18.02.21 22:55, Tobias Neumann wrote:
> Thank you. As it turns out, complex exponentiation (^ : % -> %) with a 
> Complex(DoubleFloat) exponent is also broken:
> 
> Good:
> (7) -> (-1.0 :: Complex(Float))^(0.5)
> 
>    (7)  0.2022266248_7959507324 E -20 + %i
>                                                          Type: 
> Complex(Float)
> 
> Broken:
> (6) -> (-1.0 :: Complex(DoubleFloat))^(0.5)
> 
>    (6)  6.123233995736766e-17 - %i
>                                                    Type: 
> Complex(DoubleFloat)
> 
> 
>>
> 

-- 
You received this message because you are subscribed to the Google Groups 
"FriCAS - computer algebra system" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/fricas-devel/d540695f-c238-fad0-c052-1c67821be013%40hemmecke.org.

Reply via email to