How we can compute Euler angles from Quaternion form?

[Algabri]

I am trying to use the Quaternion form instead of rotation matrices.

I already trained my model, but when I need to test the model, I must compute Euler angles from the Quaternion form as you did with computing Euler angles from rotation matrices.

For example, the output in Quaternion form for B = batch_size = 2 (-> Bx4) is :

 tensor([[ 0.0725, -0.0645,  0.0308,  0.9948],
        [-0.5235, -0.2456,  0.0824,  0.8117]], device='cuda:0')

And, the output in rotation matrices form for B = batch_size = 2 (-> Bx3x3) :

tensor([[[ 0.9933, -0.0871,  0.0755],
         [ 0.0850,  0.9959,  0.0316],
         [-0.0779, -0.0250,  0.9966]],

        [[ 0.7244, -0.0551, -0.6871],
         [ 0.2493,  0.9503,  0.1866],
         [ 0.6427, -0.3065,  0.7021]]], device='cuda:0')

Could you help me with how we can compute Euler angles from Quaternion form?

[papagina]

you could first compute the rotation matrix from quaternion and then compute the Euler angles from the rotation matrix.