* Is there something wrong with complex atan in guile?
@ 2015-07-22 11:07 Tommi Höynälänmaa
2015-07-22 22:42 ` Mark H Weaver
0 siblings, 1 reply; 3+ messages in thread
From: Tommi Höynälänmaa @ 2015-07-22 11:07 UTC (permalink / raw)
To: guile-devel
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I get the following results with guile 2.0.9:
---cut here---
scheme@(guile-user)> (atan (tan -0.5+2.0i))
$1 = 1.070796326794897+1.9999999999999996i
scheme@(guile-user)> (tan (atan -0.5+2.0i))
$2 = 0.1176470588235294+0.4705882352941177i
---cut here---
Although there are multiple branches in the complex atan function the
previous results do not seem correct. Is there something wrong here.
- Tommi
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Is there something wrong with complex atan in guile?
2015-07-22 11:07 Is there something wrong with complex atan in guile? Tommi Höynälänmaa
@ 2015-07-22 22:42 ` Mark H Weaver
2015-07-23 1:04 ` Mark H Weaver
0 siblings, 1 reply; 3+ messages in thread
From: Mark H Weaver @ 2015-07-22 22:42 UTC (permalink / raw)
To: Tommi Höynälänmaa; +Cc: guile-devel
Tommi Höynälänmaa <tommi.hoynalanmaa@gmail.com> writes:
> I get the following results with guile 2.0.9:
>
> ---cut here---
> scheme@(guile-user)> (atan (tan -0.5+2.0i))
> $1 = 1.070796326794897+1.9999999999999996i
> scheme@(guile-user)> (tan (atan -0.5+2.0i))
> $2 = 0.1176470588235294+0.4705882352941177i
> ---cut here---
>
> Although there are multiple branches in the complex atan function the
> previous results do not seem correct. Is there something wrong here.
You're right, our atan procedure was broken in commit
ad79736c68a803a59814fbfc0cb4b092c2b4cddf. I will fix it before the
2.0.12 release, and review the other changes made in that commit.
Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Is there something wrong with complex atan in guile?
2015-07-22 22:42 ` Mark H Weaver
@ 2015-07-23 1:04 ` Mark H Weaver
0 siblings, 0 replies; 3+ messages in thread
From: Mark H Weaver @ 2015-07-23 1:04 UTC (permalink / raw)
To: Tommi Höynälänmaa; +Cc: guile-devel
Mark H Weaver <mhw@netris.org> writes:
> Tommi Höynälänmaa <tommi.hoynalanmaa@gmail.com> writes:
>
>> I get the following results with guile 2.0.9:
>>
>> ---cut here---
>> scheme@(guile-user)> (atan (tan -0.5+2.0i))
>> $1 = 1.070796326794897+1.9999999999999996i
>> scheme@(guile-user)> (tan (atan -0.5+2.0i))
>> $2 = 0.1176470588235294+0.4705882352941177i
>> ---cut here---
>>
>> Although there are multiple branches in the complex atan function the
>> previous results do not seem correct. Is there something wrong here.
>
> You're right, our atan procedure was broken in commit
> ad79736c68a803a59814fbfc0cb4b092c2b4cddf. I will fix it before the
> 2.0.12 release, and review the other changes made in that commit.
Fixed in commit e3c59bfb8d822526d8cff3993ff653ac0d2b2961 on the
stable-2.0 branch.
Thanks,
Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
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