Comments (4)
It's not wrong; it's just the choice I made. I made that choice for consistency with another package I was using at the time. I agree that including the square-root is more common, but some sources do give the norm as simply the sum of the squares. You might also be interested in the abs
method, which does take the square-root.
from quaternion.
For the record: I just realized that this choice for the definitions of abs
and norm
agrees with the same functions in the boost::math::quaternion
implementation, as well as the official C++ standard for complex numbers.
from quaternion.
Very confusing indeed. Why call "norm" something that is not a norm? Renaming it to something like ceyley_seminorm
would be an improvement in my opinion
from quaternion.
Renaming it to something like
ceyley_seminorm
would be an improvement in my opinion
Well, first of all, that would involve misspelling "Cayley". Second, this is not a seminorm as distinct from a norm because it does not send any nonzero quaternion to zero; referring to it as a seminorm would suggest otherwise.
Why call "norm" something that is not a norm?
Well, there are several reasons. First, it actually is a norm — but there are different conventions for what precisely "norm" refers to [see my comments above, or the very wikipedia article that you linked to]. In particular, the wikipedia article you link to defines a norm for a vector space and while quaternions do form a vector space, they also do more than that: they form an algebra. And specifically in the context of algebras, it is more common to use the word "norm" in reference to the squared version.
Second, this is the choice consistent with the Boost implementation of quaternions, as well as python/numpy's implementation of complex numbers, plus the C++ standard for complex numbers [see my comments above, again].
Third, because I don't code for the lowest common denominator, tazr; you should probably learn to read, code for yourself, or stop complaining.
from quaternion.
Related Issues (20)
- osx-arm64 conda HOT 1
- [2022.2.9.19.55.57] Numpy compatibility with Linux wheel HOT 3
- Add a function to rotate vector with a quaternion HOT 6
- Error while running quaternion.as_rotation_matrix HOT 1
- None check fails HOT 1
- angular_velocity() output format HOT 2
- Euler angles are horrible, and so are quaternions HOT 2
- Documentation should clarify that the quaternions are defined using an active rotation convention HOT 2
- `np.sum` breaks in latest Numpy
- Object mode fallback deprecation in numba.jit
- Version number of latest release HOT 1
- Add a rotation example into the documentation HOT 1
- possible docstring error HOT 2
- add from_euler_angles equivalent for Tait-Bryan angles HOT 1
- slight improvement to "Why Euler angles are horrible"
- Identity decorator exception HOT 1
- Scalar quaternion objects are mutable HOT 1
- `cumprod()` with quaternions crashes HOT 5
- Computation Error: from euler angles to quaternion HOT 1
- Build problem on arm32v7 HOT 2
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from quaternion.