Who wants to help me balance a segway? ( fun, I hope )

Moderator
Posts: 3,577
Joined: 2003.06
Post: #16
No way! A fifth of a circle is 360/5 -- which as you will note, does not require a constant to communicate Rasp
Quote this message in a reply
Sage
Posts: 1,199
Joined: 2004.10
Post: #17
Well, for what it's worth, internally I use radians. I'm only converting to degrees at the GUI level when I set the display value on the label.

I've always been at odds about the radians/degrees debate. Degrees are more convenient to napkin-level math where I want an actual number. Radians are more convenient when I'm not interested in a number but rather an algorithm.
Quote this message in a reply
Member
Posts: 567
Joined: 2004.07
Post: #18
AnotherJake Wrote:No way! A fifth of a circle is 360/5 -- which as you will note, does not require a constant to communicate Rasp

yes it does—the last time I checked, 360 is a constant. It hasn't become 359 or 361, has it? Sneaky

It's not magic, it's Ruby.
Quote this message in a reply
Moderator
Posts: 3,577
Joined: 2003.06
Post: #19
Nayr Wrote:yes it does—the last time I checked, 360 is a constant. It hasn't become 359 or 361, has it? Sneaky

Haha. Okay, you got me... How about non-numeric symbolic glyph?
Quote this message in a reply
Sage
Posts: 1,199
Joined: 2004.10
Post: #20
I see no problem with M_PI or math.pi...
Quote this message in a reply
DoG
Moderator
Posts: 869
Joined: 2003.01
Post: #21
Degrees start to be a headache when you deal with physical properties or signal processing algorithms, where using degrees would require you to juggle around a lot more useless facors Smile
Quote this message in a reply
Moderator
Posts: 3,577
Joined: 2003.06
Post: #22
DoG Wrote:Degrees start to be a headache when you deal with physical properties or signal processing algorithms, where using degrees would require you to juggle around a lot more useless facors Smile
I agree that there are times when radians are a little more convenient, but I don't use radians for signal analysis and processing either -- if I can avoid it. The only headache to me is the annoyance of constantly converting formulas.

[small math rant] Most engineers and academics *love* writing their precious discoveries in the most esoteric manner possible. And if they don't then the people who study/publish their work do. Degrees are apparently only used by third-graders, even though the resultant math is exactly the same. [/math rant]

BTW, TomorrowPlusX, to be clear, I wasn't complaining about π, that would be silly! I was complaining about how radians have to be described using it.
Quote this message in a reply
Luminary
Posts: 5,143
Joined: 2002.04
Post: #23
Radians are "unitless", that's why they're used. If you use radians, the unit of rotations per second is Hz (1/s); if you use degrees, it's degrees per second (180/Ï€s I think).

I agree that for a user interface, degrees is probably the right choice, but internally, there's no reason at all to use anything other than radians.
Quote this message in a reply
Member
Posts: 567
Joined: 2004.07
Post: #24
well, technically, radians use the radius of the given circle as a unit. Hence the name.

It's not magic, it's Ruby.
Quote this message in a reply
Moderator
Posts: 3,577
Joined: 2003.06
Post: #25
OneSadCookie Wrote:Radians are "unitless", that's why they're used. If you use radians, the unit of rotations per second is Hz (1/s); if you use degrees, it's degrees per second (180/Ï€s I think).

1 cycle per second = 360 degrees per second = 1 Hertz = 2Ï€ radians per second

A radian cannot be unitless because it is a unit of angle! There is no real reason NOT to use degrees internally, other than radians might be more convenient to use in any given formula. Heck, glRotate takes degrees!
Quote this message in a reply
Luminary
Posts: 5,143
Joined: 2002.04
Post: #26
glRotate takes degrees, at which point it does a useless multiplication to turn 'em into radians so that they're useful... one of the silliest APIs ever, given that you'll usually have to convert radians *to* degrees to pass in the angle...

http://mathforum.org/library/drmath/view/64034.html
Quote this message in a reply
DoG
Moderator
Posts: 869
Joined: 2003.01
Post: #27
AnotherJake Wrote:A radian cannot be unitless because it is a unit of angle!

Errr ... sorry to disappoint, but that is wrong. An angle is generally dimensionless. A radian, by definition, is a ratio of two lengths, therefore by definition dimensionless. If a radian wasn't dimensionless you couldn't write 1 Hz = 1/s = 2Ï€ rad/s.
Quote this message in a reply
Moderator
Posts: 3,577
Joined: 2003.06
Post: #28
dimensionless yes, but not unitless
Quote this message in a reply
DoG
Moderator
Posts: 869
Joined: 2003.01
Post: #29
AnotherJake Wrote:dimensionless yes, but not unitless
You'll have to explain that one Smile
Quote this message in a reply
Moderator
Posts: 3,577
Joined: 2003.06
Post: #30
DoG Wrote:You'll have to explain that one Smile

Well, I wish I could, but I'm just going by what I've been told. Radians are clearly units although they describe a unitless ratio. I'm not a mathematician, so maybe I'm getting confused about where radians sit in the grander scheme of things...
Quote this message in a reply
Post Reply