Re: [Numpy-discussion] composing Euler rotation matrices

2017-02-01 Thread Seb
On Wed, 1 Feb 2017 09:42:15 +, Matthew Brett wrote: > Hi, > On Wed, Feb 1, 2017 at 8:28 AM, Robert McLeod wrote: >> Instead of trying to decipher what someone wrote on a Wikipedia, why >> don't you look at a working piece of source code? >>

Re: [Numpy-discussion] composing Euler rotation matrices

2017-02-01 Thread Stuart Reynolds
[off topic] Nothing good ever comes from using Euler matrices. All the cool kids a using quaternions these days. They're (in some ways) simpler, can be interpolated easily, don't suffer from gimbal lock (discontinuity), and are not confused about which axis rotation is applied first (for Euler you

Re: [Numpy-discussion] composing Euler rotation matrices

2017-02-01 Thread Matthew Brett
Hi, On Wed, Feb 1, 2017 at 8:28 AM, Robert McLeod wrote: > Instead of trying to decipher what someone wrote on a Wikipedia, why don't > you look at a working piece of source code? > > e.g. > > https://github.com/3dem/relion/blob/master/src/euler.cpp Also - have a look at

Re: [Numpy-discussion] composing Euler rotation matrices

2017-02-01 Thread Robert McLeod
Instead of trying to decipher what someone wrote on a Wikipedia, why don't you look at a working piece of source code? e.g. https://github.com/3dem/relion/blob/master/src/euler.cpp Robert On Wed, Feb 1, 2017 at 4:27 AM, Seb wrote: > On Tue, 31 Jan 2017 21:23:55 -0500, >

Re: [Numpy-discussion] composing Euler rotation matrices

2017-01-31 Thread Seb
On Tue, 31 Jan 2017 21:23:55 -0500, Joseph Fox-Rabinovitz wrote: > Could you show what you are doing to get the statement "However, I > cannot reproduce this matrix via composition; i.e. by multiplying the > underlying rotation matrices.". I would guess something

Re: [Numpy-discussion] composing Euler rotation matrices

2017-01-31 Thread Joseph Fox-Rabinovitz
Could you show what you are doing to get the statement "However, I cannot reproduce this matrix via composition; i.e. by multiplying the underlying rotation matrices.". I would guess something involving the `*` operator instead of `@`, but guessing probably won't help you solve your issue.

[Numpy-discussion] composing Euler rotation matrices

2017-01-31 Thread Seb
Hello, I'm trying to compose Euler rotation matrices shown in https://en.wikipedia.org/wiki/Euler_angles#Rotation_matrix. For example, The Z1Y2X3 Tait-Bryan rotation shown in the table can be represented in Numpy using the function: def z1y2x3(alpha, beta, gamma): """Rotation matrix given