H-field inside for Cylinder and Cylinder Segment does not match #703
Description
Magpylib version
4.x (Latest)
What happened?
When computing the H-field inside a cylinder, the values do not match the values obtained with an equivalent cylinder segment.
@OrtnerMichael Shall we wait for the v5 release or make a hotfix for v4 already now?
Code example
import magpylib as magpy
import numpy as np
field = "H"
obs = np.array([(0.1, 0.2, 0.3)])
pols = np.array([(0, 0, 1)] * len(obs))
d,h = 1,1
dims = np.array([(d, h)]*len(obs))
dims_cs = np.array([(0, d/2, h, 0, 360)]*len(obs))
Bc = magpy.core.magnet_cylinder_field(
field=field,
observers=obs,
dimension=dims,
magnetization=pols,
)
Bcs = magpy.core.magnet_cylinder_segment_field(
field=field,
observers=obs,
dimension=dims_cs,
magnetization=pols,
)
print(Bc, Bcs)
# ->output :
#(array([[0.02672707, 0.05345415, 0.50743767]]),
# array([[ 0.02672707, 0.05345415, -0.28833704]]))Additional context
Cylinder field function axial vs transversal mask. seems to be the issue
if any(mask_ax): # ax computes B-field
Bz[mask_tv * mask_inside] -= magz[mask_tv * mask_inside]
return np.concatenate(((Bx,), (By,), (Bz,)), axis=0).T * 10 / 4 / np.pi
```
([permalink](https://github.com/magpylib/magpylib/blob/e35b724a8154903d2c6710edb1d254105d884f88/magpylib/_src/fields/field_BH_cylinder.py#L388C5-L389C65))