Change 'j' for imaginary unit into an 'i'

[Retro]

BPO	10562
Nosy	@malemburg, @gvanrossum, @ncoghlan, @merwok, @briancurtin, @ericsnowcurrently

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2011-11-21.19:26:59.297>
created_at = <Date 2010-11-28.15:19:14.854>
labels = ['interpreter-core', 'type-feature']
title = "Change 'j' for imaginary unit into an 'i'"
updated_at = <Date 2011-11-21.20:12:36.555>
user = 'https://bugs.python.org/Retro'

bugs.python.org fields:

activity = <Date 2011-11-21.20:12:36.555>
actor = 'gvanrossum'
assignee = 'none'
closed = True
closed_date = <Date 2011-11-21.19:26:59.297>
closer = 'brian.curtin'
components = ['Interpreter Core']
creation = <Date 2010-11-28.15:19:14.854>
creator = 'Retro'
dependencies = []
files = []
hgrepos = []
issue_num = 10562
keywords = []
message_count = 60.0
messages = ['122662', '122663', '122669', '122672', '122722', '122728', '122729', '122730', '122731', '122732', '122733', '122734', '123101', '123102', '123105', '123106', '123108', '123110', '123111', '123112', '123114', '123115', '123117', '123118', '123119', '123120', '123121', '123122', '123127', '123131', '123134', '123135', '123140', '123146', '123179', '123188', '123189', '123200', '123208', '123212', '123217', '123219', '123220', '123235', '123245', '123256', '123269', '123272', '123274', '123276', '123279', '123281', '148010', '148011', '148015', '148071', '148072', '148073', '148081', '148083']
nosy_count = 8.0
nosy_names = ['lemburg', 'gvanrossum', 'ncoghlan', 'lehmannro', 'eric.araujo', 'Retro', 'brian.curtin', 'eric.snow']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue10562'
versions = ['Python 3.3']

[Retro]

In Python, the letter 'j' denotes the imaginary unit. It would be great if we would follow mathematics in this regard and let the imaginary unit be denoted with an 'i'.

[voidspace]

We follow engineering which uses j.

(I was about to close this as wontfix but Antoine is particularly keen that Mark deals with this issue...)

[mdickinson]

Glad to oblige. :-)

[mdickinson]

Just to add my own thoughts: 'j' for *a* (not *the* </pedantry>) square root of -1 has, as Michael points out, a history of use in engineering (particularly electrical engineering) and physics. Personally, I would have preferred 'i' to 'j' here, but changing it now would cause (IMO) gratuitous breakage. It really doesn't seem a big enough issue to be worth making a fuss about.

[Retro]

"The Python programming language also uses j to denote the imaginary unit.
MATLAB associates both i and j with the imaginary unit."
-Wikipedia<http://en.wikipedia.org/wiki/Imaginary_unit#Alternative_notations\>

It would be a welcome feature in Python if the programming language would,
like MATLAB, associate both i and j with the imaginary unit.

[abalkin]

Why not allow complex('1i')?

(Tongue in cheek: I am really looking for arguments against lax parsing in number builtins. See bpo-10557.)

[mdickinson]

It would be a welcome feature in Python if the programming language
would, like MATLAB, associate both i and j with the imaginary unit.

I suggest taking this to the python-ideas mailing list. A working patch might increase the idea's chances.

[mdickinson]

Why not allow complex('1i')?

Indeed, if 4i were permitted as an imaginary literal, I'd expect to allow complex('3 + 4i') as well.

(And possible just plain complex('i') too, since complex('j') is currently allowed. Grr.)

[abalkin]

On Sun, Nov 28, 2010 at 3:58 PM, Mark Dickinson <report@bugs.python.org> wrote:
..

I'd expect to allow complex('3 + 4i') as well.

And with spaces surrounding '+' too.

[Retro]

It would be great if the feature of having both j and i would exist in the
interpreter core, as well as the built-in function complex() to accept i.

[pitrou]

There should be an environment variable to make the symbol settable.

$ PYTHONIMAGINARYSYMBOL=i python -c "import cmath; print(cmath.sqrt(-1))"
1i