Magpylib

https://magpylib.readthedocs.io/en/latest/
Admin
Magpylib is an open-source Python package for fast, vectorized calculation of static magnetic...
Tokens:148,098
Snippets:1,287
Trust Score:9.6
Update:3 months ago
Show doc for...
Tokens:
Raw
### Define System with Paths

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_vis_subplots.html

Setup a cylinder magnet and a sensor, both with defined motion paths, to be used in subsequent visualization examples.

```python
import numpy as np
import magpylib as magpy

# Define sensor with path
cyl = magpy.magnet.Cylinder(
    polarization=(1, 0, 0),
    dimension=(2, 1),
    position=(4, 0, 0),
)
cyl.rotate_from_angax(angle=np.linspace(0, 300, 40), start=0, axis="z", anchor=0)

# Define magnet with path
sens = magpy.Sensor(
    pixel=[(-.2, 0, 0), (.2, 0, 0)],
    position = np.linspace((0, 0, -3), (0, 0, 3), 40)
)
```

--------------------------------

### Console Output Examples

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_styles.html

Expected console output when running the magnetization style demonstration.

```text
Default magnetization style
```

```text
Custom magnetization style
```

--------------------------------

### Install Magpylib via pip

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/guide_start_01_install.html

Standard installation method using the Python package manager.

```bash
pip install magpylib
```

--------------------------------

### Setup Magnet Simulation Parameters

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/examples/examples_tutorial_modeling_magnets.md.txt

Initializes the simulation environment and defines the linear motion path for the magnet.

```python
import numpy as np
import matplotlib.pyplot as plt
import magpylib as magpy

# Testbench positioning
xs = np.linspace(-15, 15, 61)
```

--------------------------------

### Minimal Force Computation Example

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_forcecomp.html

A complete example demonstrating the computation of force and torque between a cuboid magnet and a current loop.

```python
import numpy as np
import magpylib as magpy

cube = magpy.magnet.Cuboid(dimension=(1, 1, 1), polarization=(0.1, 0.2, 0.3))
loop = magpy.current.Circle(
    diameter=2,
    current=1e3,
    position=(0, 0, 1),
    meshing=40,
)
F, T = magpy.getFT(cube, loop)

print(f"force: {np.round(F, decimals=2)} N")
# force: [ 13.67  27.33 -82.  ] N

print(f"torque: {np.round(T, decimals=2)} N*m")
# torque: [-8.54  4.27  0.  ] N*m
```

--------------------------------

### Install Magpylib via conda

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/guide_start_01_install.html

Installation method for users managing environments with conda.

```bash
conda install -c conda-forge magpylib
```

--------------------------------

### Compute B-field of a TriangularMesh

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.magnet.html

Example demonstrating the initialization of a TriangularMesh and the computation of the B-field at a specific observer position.

```python
>>> import numpy as np
>>> import magpylib as magpy
>>> vv = ((0, 0, 0), (0.01, 0.0, 0.0), (0.0, 0.01, 0.0), (0.0, 0.0, 0.01))
>>> tt = ((0, 1, 2), (0, 1, 3), (0, 2, 3), (1, 2, 3))
>>> trim = magpy.magnet.TriangularMesh(
...     polarization=(0.1, 0.2, 0.3), vertices=vv, faces=tt,
... )
>>> with np.printoptions(precision=3):
...     print(trim.getB((0.01, 0.01, 0.01)) * 1000)
[2.602 2.082 1.561]
```

--------------------------------

### Minimal field computation example

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_fieldcomp.html

A basic workflow defining a source and observer to compute the magnetic field.

```python
import magpylib as magpy

# Define source and observer objects
loop = magpy.current.Circle(current=1, diameter=0.001)
sens = magpy.Sensor()

# Compute field
B = magpy.getB(loop, sens)

print(B)
#  --> [0.         0.         0.00125664]
```

--------------------------------

### Load and Simulate Magnetic Field

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/examples/examples_tutorial_modeling_magnets.md.txt

Initial setup for loading experimental data and simulating the magnetic field of a cylinder magnet.

```python
# Load experimental data
data_path = '../../../_static/data/Bomatec_LD025_scan0.npy'
Bexp = np.load(data_path)  # shape should be (61, 3)

# Simulation setup
sensor = magpy.Sensor(position=(0, 0, 0))
magnet = magpy.magnet.Cylinder(
    polarization=(0, 0, 1200), # in mT
    dimension=(8, 2),          # in mm
    position=[(x,0,7) for x in xs], # z=7 mm center height
)
Bsim = sensor.getB(magnet)

# Plotting function
def plot_field(Bsim, Bexp, xs):
    """Plot results."""
    fig, axes = plt.subplots(1, 3, figsize=(12, 3.5), sharey=True)

    labels = ['Bx Field (mT)', 'By Field (mT)', 'Bz Field (mT)']
    for i,ax in enumerate(axes):
        ax.plot(xs, Bsim[:, i], color='b', label='Simulation')
        ax.plot(xs, Bexp[:, i], ls='', marker='.', color='orange', label='Experiment')

        ax.set_title(labels[i])
        ax.set_xlabel('Magnet Position (mm)')
        ax.grid(color='.85')
        ax.legend(loc='upper right')

    plt.tight_layout()
    plt.show()

plot_field(Bsim, Bexp, xs)
```

--------------------------------

### Calculate B-field with Magpylib

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Examples demonstrating magnetic field calculation for various source and observer configurations.

```python
>>> import numpy as np
>>> import magpylib as magpy
>>> loop = magpy.current.Circle(current=100, diameter=0.002)
>>> sph = magpy.magnet.Sphere(polarization=(0.0, 0.0, 0.1), diameter=0.001)
>>> B = magpy.getB([loop, sph], (0.01, 0.01, 0.01))
>>> with np.printoptions(precision=3):
...     print(B)
[[ 6.054e-06  6.054e-06  2.357e-08]
[ 8.019e-07  8.019e-07 -9.056e-23]]
```

```python
>>> s1 = magpy.Sensor(position=(0.01, 0.01, 0.01))
>>> s2 = s1.copy(position=(0.01, 0.01, -0.01))
>>> B = magpy.getB([loop, sph], [s1, s2])
>>> with np.printoptions(precision=3):
...     print(B)
[[[ 6.054e-06  6.054e-06  2.357e-08]
[-6.054e-06 -6.054e-06  2.357e-08]]

[[ 8.019e-07  8.019e-07 -9.056e-23]
[-8.019e-07 -8.019e-07 -9.056e-23]]]
```

--------------------------------

### Configure Individual Object Styles

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_styles.html

Demonstrates setting individual styles at initialization versus after initialization, noting the performance implications of deferred style loading.

```python
import magpylib as magpy

# Reset defaults from previous example
magpy.defaults.reset()

# Default style
cube = magpy.magnet.Cuboid(
    polarization=(1, 0, 0),
    dimension=(1, 1, 1),
)

# Good practice: define individual style at object init
cylinder = magpy.magnet.Cylinder(
    polarization=(0, 1, 0),
    dimension=(1, 1),
    position=(2, 0, 0),
    style_magnetization_color_mode="tricycle",
)

# Bad practice: set individual style after object init
sphere = magpy.magnet.Sphere(
    polarization=(0, 1, 1),
    diameter=1,
    position=(4, 0, 0),
)
sphere.style.magnetization.color.mode = "bicolor"

# Show styled objects
magpy.show(cube, cylinder, sphere, backend="plotly")
```

--------------------------------

### Apply move operation with start index

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.misc.html

Applies a displacement starting from a specific path index.

```python
>>> sens.move((0, 0, 2), start=2)
Sensor(id=...)
>>> print(sens.position)
[[2. 2. 2.]
 [3. 3. 3.]
 [4. 4. 6.]
 [5. 5. 7.]]
```

--------------------------------

### Applying Magnet Color Schemes

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_vis_magnet_colors.html

Demonstrates configuring magnetization styles using dictionaries, direct keyword arguments, and object attribute assignment.

```python
import magpylib as magpy

print('APPLYING DIFFERENT MAGNET COLOR SCHEMES')

# Create a magnetization style dictionary
mstyle = dict(
    mode="color+arrow",
    color=dict(north="magenta", middle="white", south="turquoise"),
    arrow=dict(width=2, color="k")
)

# Create magnet and apply style
sphere = magpy.magnet.Sphere(
    polarization=(1, 1, 1),
    diameter=1,
    position=(-1, 1, 0),
    style_magnetization=mstyle,
)

# Create a second magnet with different style
cube = magpy.magnet.Cuboid(
    polarization=(1, 0, 0),
    dimension=(1, .2, .2),
    position=(1, 1, 0),
    style_magnetization_color_mode="bicolor",
    style_magnetization_color_north="r",
    style_magnetization_color_south="g",
    style_magnetization_color_transition=0,
)

# Create a third magnet with different style
cyl = magpy.magnet.CylinderSegment(
    polarization=(1, 0, 0),
    dimension=(1.7, 2, .3, -145, -35),
)
cyl.style.magnetization.color.north = "cornflowerblue"
cyl.style.magnetization.color.south = "orange"

# Show all three
magpy.show(sphere, cube, cyl, backend='plotly', style_legend_show=False)
```

--------------------------------

### Iterate and display with supported backends

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_graphics.html

Demonstrates how to iterate through all supported plotting backends and render objects using each one.

```python
import magpylib as magpy
import numpy as np

# Define sources and paths
loop = magpy.current.Circle(
    current=1, diameter=1, position=np.linspace((0, 0, -3), (0, 0, 3), 40)
)
cylinder = magpy.magnet.Cylinder(
    polarization=(0, -1, 0), dimension=(1, 2), position=(0, -3, 0)
)
cylinder.rotate_from_angax(np.linspace(0, 300, 40), "z", anchor=0, start=0)

for backend in magpy.SUPPORTED_PLOTTING_BACKENDS:
    print(backend)
    magpy.show(loop, cylinder, backend=backend)
```

--------------------------------

### Initialize and compute field for MagnetRing

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_misc_compound.html

Demonstrates instantiating the custom MagnetRing, performing transformations, and computing the magnetic field at a sensor.

```python
# Continuation from above - ensure previous code is executed

# Add a sensor
sensor = magpy.Sensor(position=(0, 0, 0))

# Create a MagnetRing object
ring = MagnetRing()

# Move MagnetRing around
ring.rotate_from_angax(angle=45, axis='x')

# Compute field
print(f"B-field at sensor → {ring.getB(sensor).round(2)}")

# Display graphically
magpy.show(ring, sensor, backend='plotly')
```

```text
B-field at sensor → [ 0.    0.04 -0.04]
```

--------------------------------

### Rotate objects using scipy Rotation

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Examples of rotating objects about the origin, about themselves, and creating rotation paths.

```python
>>> from scipy.spatial.transform import Rotation as R
>>> import magpylib as magpy
>>> sens = magpy.Sensor(position=(1, 0, 0))
>>> sens.rotate(R.from_euler('z', 45, degrees=True), anchor=0)
Sensor(id=...)
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 45.]
```

```python
>>> sens.rotate(R.from_euler('z', 45, degrees=True))
Sensor(id=...)
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 90.]
```

```python
>>> sens.rotate(R.from_euler('z', [[15], [30], [45]], degrees=True), anchor=(0, 0, 0))
Sensor(id=...)
>>> print(sens.position)
[[ 7.07106781e-01  7.07106781e-01  0.00000000e+00]
 [ 5.00000000e-01  8.66025404e-01  0.00000000e+00]
 [ 2.58819045e-01  9.65925826e-01  0.00000000e+00]
 [-2.22044605e-16  1.00000000e+00  0.00000000e+00]]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[[  0.   0.  90.]
 [  0.   0. 105.]
 [  0.   0. 120.]
 [  0.   0. 135.]]
```

--------------------------------

### Configure Moving and Rotating Sensors

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/examples/examples_tutorial_field_computation.md.txt

Demonstrates defining a sensor with multiple pixels and applying movement and rotation paths alongside moving source objects.

```python
import numpy as np
import magpylib as magpy

# Reset defaults set in previous example
magpy.defaults.reset()


# Define sensor with path
sensor = magpy.Sensor(pixel=[(0, 0, -0.0005), (0, 0, 0.0005)], style_size=1.5)
sensor.position = np.linspace((0, 0, -0.003), (0, 0, 0.003), 37)

angles = np.linspace(0, 360, 37)
sensor.rotate_from_angax(angles, "z", start=0)

# Define source with path
cyl1 = magpy.magnet.Cylinder(
    polarization=(0.1, 0, 0), dimension=(0.001, 0.002), position=(0.003, 0, 0)
)
cyl2 = cyl1.copy(position=(-0.003, 0, 0))
coll = magpy.Collection(cyl1, cyl2)
coll.rotate gen_from_angax(-angles, "z", start=0)

# Display system and field at sensor
with magpy.show_context(sensor, coll, animation=True, backend="plotly"):
    magpy.show(col=1)
    magpy.show(output="Bx", col=2, pixel_agg=None)
```

--------------------------------

### Add objects to a collection

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Shows how to initialize a collection with objects and add additional sensors dynamically.

```python
>>> import magpylib as magpy
>>> x1 = magpy.Sensor(style_label='x1')
>>> coll = magpy.Collection(x1, style_label='coll')
>>> coll.describe(format='label')
coll
└── x1
```

```python
>>> x2 = magpy.Sensor(style_label='x2')
>>> coll.add(x2)
Collection(id=...)
>>> coll.describe(format='label')
coll
├── x1
└── x2
```

--------------------------------

### Create Sources and Observers

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/guide_start_02_fundamentals.html

Instantiate magnetic sources like Cuboids and measurement sensors as Python objects.

```python
import magpylib as magpy

# Create a Cuboid magnet with magnetic polarization
# of 1 T pointing in x-direction and sides of
# 1, 2 and 3 cm respectively (notice the use of SI units).

cube = magpy.magnet.Cuboid(polarization=(1, 0, 0), dimension=(0.01, 0.02, 0.03))

# Create a Sensor for measuring the field

sensor = magpy.Sensor()
```

--------------------------------

### Using Show Context Manager

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/examples/examples_vis_subplots.md.txt

Utilizes a context manager to easily arrange multiple field outputs and the 3D model into a grid layout.

```python
with magpy.show_context([cyl, sens], backend='plotly') as sc:
    sc.show(output="Bx", col=1, row=1)
    sc.show(output="By", col=1, row=2)
    sc.show(output="Bz", col=2, row=1)
    sc.show(output="model3d", col=2, row=2)
```

--------------------------------

### Compute Magpylib field

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_graphics.html

Basic setup for computing magnetic fields using a circular loop and a sensor array.

```python
import magpylib as magpy
import numpy as np

# Magpylib field computation
loop = magpy.current.Circle(current=1, diameter=0.1)
sens = magpy.Sensor(position=np.linspace((0, 0, -0.1), (0, 0, 0.1), 100))
B = loop.getB(sens)
```

--------------------------------

### Add and manipulate 3D traces with generic backend

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_styles.html

Demonstrates adding multiple Scatter3d traces to a sensor and manipulating copied Trace3d objects.

```python
# Continuation from above - ensure previous code is executed

import copy
import numpy as np

# Generate trace and add to sensor
ts = np.linspace(0, 2 * np.pi, 30)
trace_scatter3d = {
    "backend": "generic",
    "constructor": "Scatter3d",
    "kwargs": {
        "x": 1.2*np.cos(ts),
        "y": 1.2*np.sin(ts),
        "z": np.zeros(30),
        "mode": "lines",
    },
}
sensor.style.model3d.add_trace(trace_scatter3d)

# Generate new trace from Trace3d object
trace2 = copy.deepcopy(sensor.style.model3d.data[1])
trace2.kwargs["x"] = np.zeros(30)
trace2.kwargs["z"] = 1.2*np.cos(ts)

sensor.style.model3d.add_trace(trace2)

# Show
magpy.show(sensor)
```

--------------------------------

### Create a simple animation

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_vis_animations.html

Uses the show() function with animation=True to animate objects defined with motion paths.

```python
import magpylib as magpy
import numpy as np

# Define magnet with path
magnet = magpy.magnet.Cylinder(
    polarization=(1, 0, 0),
    dimension=(2, 1),
    position=(4, 0, 0),
    style_label="magnet",
)
magnet.rotate_from_angax(angle=np.linspace(0, 300, 40), start=0, axis="z", anchor=0)

# Define sensor with path
sensor = magpy.Sensor(
    pixel=[(-0.2, 0, 0), (0.2, 0, 0)],
    position=np.linspace((0, 0, -3), (0, 0, 3), 40),
    style_label="sensor",
)

# Display as animation - prefers plotly backend
magpy.show(sensor, magnet, animation=True, backend="plotly")
```

--------------------------------

### Pyvista backend warning message

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_styles.html

Warning message displayed when using the Pyvista backend in a notebook environment without trame installed.

```text
2026-07-09 13:01:48.039 (   0.289s) [    789BA1ABBB80]vtkXOpenGLRenderWindow.:1460  WARN| bad X server connection. DISPLAY=
/home/docs/checkouts/readthedocs.org/user_builds/magpylib/checkouts/latest/src/magpylib/_src/display/backend_pyvista.py:366: UserWarning:

Using static image for notebook display.
Install trame for interactive backends: pip install "pyvista[jupyter]"
```

--------------------------------

### Pyvista Deprecation Error Traceback

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_vis_pv_streamlines.html

Example of a DeprecationError encountered when using the deprecated max_time parameter in Pyvista's streamlines_from_source method.

```text
---------------------------------------------------------------------------
DeprecationError                          Traceback (most recent call last)
Cell In[1], line 19
     15 grid["B"] = magnet.getB(grid.points) * 1000  # T -> mT
     16 
     17 # Compute the field lines
     18 seed = pv.Disc(inner=0.001, outer=0.003, r_res=1, c_res=9)
---> 19 strl = grid.streamlines_from_source(
     20     seed,
     21     vectors="B",
     22     max_step_length=0.1,

File ~/checkouts/readthedocs.org/user_builds/magpylib/checkouts/latest/.venv/lib/python3.13/site-packages/pyvista/_deprecate_positional_args.py:243, in _deprecate_positional_args.<locals>._inner_deprecate_positional_args.<locals>.inner_f(*args, **kwargs)
    239             warn_external(msg, PyVistaDeprecationWarning)
    241         warn_positional_args()
--> 243 return f(*args, **kwargs)

File ~/checkouts/readthedocs.org/user_builds/magpylib/checkouts/latest/.venv/lib/python3.13/site-packages/pyvista/core/filters/data_set.py:3675, in DataSetFilters.streamlines_from_source(self, source, vectors, integrator_type, integration_direction, surface_streamlines, initial_step_length, step_unit, min_step_length, max_step_length, max_steps, terminal_speed, max_error, max_time, compute_vorticity, rotation_scale, interpolator_type, progress_bar, max_length)
   3670 if max_time is not None:
   3671     msg = (
   3672         '``max_time`` parameter is deprecated and no longer supported. '
   3673         'Use ``max_length`` instead.'
   3674     )
-> 3675     raise DeprecationError(msg)
   3677 if max_length is None:
   3678     max_length = 4.0 * self.GetLength()

DeprecationError: ``max_time`` parameter is deprecated and no longer supported. Use ``max_length`` instead.
```

--------------------------------

### Initialize TriangularMesh

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_classes.html

Constructor signature for creating a TriangularMesh object with specified geometry and magnetization properties.

```python
magpylib.magnet.TriangularMesh(
    position,
    orientation,
    vertices,
    faces,
    polarization,
    magnetization,
    meshing,
    check_open,
    check_disconnected,
    check_selfintersecting,
    reorient_faces,
    style,
)
```

--------------------------------

### Merge Multiple Path Operations

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_tutorial_paths.html

Combine linear movement and multiple rotations by specifying start indices to create complex motion paths.

```python
import numpy as np
from magpylib.magnet import Cuboid

# Create cube and set linear path
cube = Cuboid(polarization=(0, 0, 0.1), dimension=(0.02, 0.02, 0.02))
cube.position = np.linspace((0, 0, 0), (0.1, 0, 0), 60)

# Apply rotation about self - starting at index 0
cube.rotate_from_rotvec(np.linspace((0, 0, 0), (0, 0, 360), 30), start=0)

# Apply rotation about origin - starting at index 30
cube.rotate_from_rotvec(np.linspace((0, 0, 0), (0, 0, 360), 30), anchor=0, start=30)

# Display paths as animation
cube.show(backend="plotly", animation=True)
```

--------------------------------

### Equivalent show_context Usage Patterns

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/docs/docs_graphics.md.txt

Demonstrates that calling show() on the context manager object is equivalent to calling magpy.show() directly within the context block.

```python
import magpylib as magpy

obj1 = magpy.magnet.Cuboid()
obj2 = magpy.magnet.Cylinder()

with magpy.show_context() as sc:
    sc.show(obj1, col=1)
    sc.show(obj2, col=2)
```

```python
import magpylib as magpy

obj1 = magpy.magnet.Cuboid()
obj2 = magpy.magnet.Cylinder()

with magpy.show_context():
    magpy.show(obj1, col=1)
    magpy.show(obj2, col=2)
```

--------------------------------

### Rotate an object using angle-axis

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.misc.html

Examples of rotating objects using the rotate_from_angax method, covering rotation about the origin, about the object itself, and creating multi-step paths.

```python
>>> import magpylib as magpy
>>> sens = magpy.Sensor(position=(1, 0, 0))
>>> sens.rotate_from_angax(45, axis='z', anchor=0)
Sensor(id=...)
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 45.]
```

```python
>>> sens.rotate_from_angax(45, axis=(0, 0, 1))
Sensor(id=...)
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 90.]
```

```python
>>> sens.rotate_from_angax((15, 30, 45), axis='z', anchor=(0, 0, 0))
Sensor(id=...)
>>> print(sens.position)
[[ 7.07106781e-01  7.07106781e-01  0.00000000e+00]
 [ 5.00000000e-01  8.66025404e-01  0.00000000e+00]
 [ 2.58819045e-01  9.65925826e-01  0.00000000e+00]
 [-2.22044605e-16  1.00000000e+00  0.00000000e+00]]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[[  0.   0.  90.]
 [  0.   0. 105.]
 [  0.   0. 120.]
 [  0.   0. 135.]]
```

--------------------------------

### Compute B-field with Sensor

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Compute the magnetic B-field in Tesla as seen by a sensor. Examples demonstrate basic computation, rotation, and pixel-based field sensing.

```python
>>> import numpy as np
>>> import magpylib as magpy
>>> sens = magpy.Sensor()
>>> loop = magpy.current.Circle(current=1, diameter=0.01)
>>> B = sens.getB(loop)
>>> with np.printoptions(precision=3):
...     print(B*1000)
[0.    0.    0.126]
```

```python
>>> sens.rotate_from_rotvec((45, 0, 0))
Sensor(id=...)
>>> B = sens.getB(loop)
>>> with np.printoptions(precision=3):
...     print(B)
[0.000e+00 8.886e-05 8.886e-05]
```

```python
>>> sens.pixel = ((0, 0, 0), (0.001, 0, 0), (0.002, 0, 0))
>>> B = sens.getB(loop)
>>> with np.printoptions(precision=3):
...     print(B)
[[0.000e+00 8.886e-05 8.886e-05]
 [0.000e+00 9.163e-05 9.163e-05]
 [0.000e+00 1.014e-04 1.014e-04]]
```

--------------------------------

### Convergence Analysis with Reciprocity

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_force_intro.html

Demonstrates how to evaluate force and torque convergence by comparing numerical results against an exact solution using reciprocity.

```python
import numpy as np
import magpylib as magpy

dipole = magpy.misc.Dipole(moment=(0, 0, 1e6), position=(1, 1, 1))
loop = magpy.current.Circle(diameter=1, current=1)

# Forward (exact)
F0, T0 = magpy.getFT(loop, dipole, pivot=(0, 0, 0))

# Backward (numerical), has opposite sign
for meshing in [8, 40, 200, 1000]:

    # Set meshing parameter
    loop.meshing = meshing

    # Compute backward force and torque
    F1, T1 = magpy.getFT(dipole, loop, pivot=(0, 0, 0))

    # Compute vectorwise relative error
    errF = np.linalg.norm(F1 + F0) / np.linalg.norm(F0)
    errT = np.linalg.norm(T1 + T0) / np.linalg.norm(T0)

    print(f"Meshing: {meshing:>4}, Force Error: {errF:.2e}, Torque Error: {errT:.2e}")

# Meshing:    8, Force Error: 1.02e-02, Torque Error: 3.93e-03
# Meshing:   40, Force Error: 3.82e-04, Torque Error: 8.30e-05
# Meshing:  200, Force Error: 1.53e-05, Torque Error: 3.31e-06
# Meshing: 1000, Force Error: 6.12e-07, Torque Error: 1.33e-07
```

--------------------------------

### Initialize CylinderSegment Magnet

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_classes.html

Defines a magnet as a cylindrical ring section with dimensions (inner radius, outer radius, height, start angle, end angle).

```python
magpylib.magnet.CylinderSegment(
    position, orientation, dimension, polarization, magnetization, meshing, style
)
```

--------------------------------

### Use and manipulate the MagnetRing compound

Source: https://magpylib.readthedocs.io/en/latest/_sources/_pages/user_guide/examples/examples_misc_compound.md.txt

Demonstrates initializing the custom compound, applying transformations, and computing magnetic fields.

```python
# Continuation from above - ensure previous code is executed

# Add a sensor
sensor = magpy.Sensor(position=(0, 0, 0))

# Create a MagnetRing object
ring = MagnetRing()

# Move MagnetRing around
ring.rotate_from_angax(angle=45, axis='x')

# Compute field
print(f"B-field at sensor → {ring.getB(sensor).round(2)}")

# Display graphically
magpy.show(ring, sensor, backend='plotly')
```

--------------------------------

### Manipulating Object Paths with Move

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_pos_ori.html

Demonstrates how scalar and vector inputs affect object paths, including the use of the start parameter to control where operations are applied.

```python
import magpylib as magpy

# Note that all units are in SI

sensor = magpy.Sensor()
print(sensor.position)  # Default value
#   --> [0. 0. 0.]

sensor.move((1, 1, 1))  # Scalar input is by default applied
print(sensor.position)  # to the whole path
#   --> [1. 1. 1.]

sensor.move([(1, 1, 1), (2, 2, 2)])  # Vector input is by default appended
print(sensor.position)  # to the existing path
#   --> [[1. 1. 1.]  [2. 2. 2.]  [3. 3. 3.]]

sensor.move((1, 1, 1), start=1)  # Scalar input and start=1 is applied
print(sensor.position)  # to whole path starting at index 1
#   --> [[1. 1. 1.]  [3. 3. 3.]  [4. 4. 4.]]

sensor.move([(0, 0, 10), (0, 0, 20)], start=1)  # Vector input and start=1 merges
print(sensor.position)  # the input with the existing path
#   --> [[ 1.  1.  1.]  [ 3.  3. 13.]  [ 4.  4. 24.]]     # starting at index 1.
```

--------------------------------

### Rotate Object using Euler Angles

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Examples of rotating objects using Euler angles, including rotation about the origin, about the object itself, and creating a rotation path.

```python
>>> import magpylib as magpy
>>> sens = magpy.Sensor(position=(1, 0, 0))
>>> sens.rotate_from_euler(45, 'z', anchor=0)
Sensor...
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 45.]
```

```python
>>> sens.rotate_from_euler(45, 'z')
Sensor(id=...)
>>> print(sens.position)
[0.70710678 0.70710678 0.        ]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[ 0.  0. 90.]
```

```python
>>> sens.rotate_from_euler((15, 30, 45), 'z', anchor=(0, 0, 0))
Sensor(id=...)
>>> print(sens.position)
[[ 7.07106781e-01  7.07106781e-01  0.00000000e+00]
 [ 5.00000000e-01  8.66025404e-01  0.00000000e+00]
 [ 2.58819045e-01  9.65925826e-01  0.00000000e+00]
 [-2.22044605e-16  1.00000000e+00  0.00000000e+00]]
>>> print(sens.orientation.as_euler('xyz', degrees=True))
[[  0.   0.  90.]
 [  0.   0. 105.]
 [  0.   0. 120.]
 [  0.   0. 135.]]
```

--------------------------------

### show

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Displays objects and their paths graphically.

```APIDOC
## show(*, backend=None, canvas=None, animation=None, zoom=None, markers=None, return_fig=None, canvas_update=None, row=None, col=None, output=None, sumup=None, pixel_agg=None, style=None, **kwargs)

### Description
Display objects and paths graphically. Global graphic styles can be set using kwargs or style dictionaries.
```

--------------------------------

### Initialize CustomSource

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/docs/docs_classes.html

Creates a user-defined source using a custom field computation function that must accept field type and observer positions.

```python
magpylib.misc.CustomSource(field_func, position, orientation, style)
```

--------------------------------

### Create and Manipulate a Collection

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Demonstrates creating a collection with two sources and moving the entire group, which updates the positions of all children.

```python
>>> import numpy as np
>>> import magpylib as magpy
>>> src1 = magpy.magnet.Sphere(position=(2, 0, 0), diameter=1, polarization=(0.1, 0.2, 0.3))
>>> src2 = magpy.current.Circle(position=(-2, 0, 0), diameter=1, current=1)
>>> col = magpy.Collection(src1, src2)
>>> col.move((0, 0, 2))
Collection(id=...)
>>> print(src1.position)
[2. 0. 2.]
>>> print(src2.position)
[-2.  0.  2.]
>>> print(col.position)
[0. 0. 2.]
```

--------------------------------

### Manipulate Collections and Animations

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_tutorial_collection.html

Demonstrates creating a Helmholtz coil collection, applying movement and rotation to sub-groups, and generating an animation.

```python
import numpy as np
import magpylib as magpy

# Construct two coils from windings
coil1 = magpy.Collection(style_label="coil1")
for z in np.linspace(-0.0005, 0.0005, 5):
    coil1.add(magpy.current.Circle(current=1, diameter=0.02, position=(0, 0, z)))
coil1.position = (0, 0, -0.005)
coil2 = coil1.copy(position=(0, 0, 0.005))

# Helmholtz consists of two coils
helmholtz = coil1 + coil2

# Move the helmholtz
helmholtz.position = np.linspace((0, 0, 0), (0.01, 0, 0), 15)
helmholtz.rotate_from_angax(np.linspace(0, 180, 15), "x", start=0)

# Move the coils
coil1.move(np.linspace((0, 0, 0), (0.005, 0, 0), 15))
coil2.move(np.linspace((0, 0, 0), (-0.005, 0, 0), 15))

# Move the windings
for coil in [coil1, coil2]:
    for i, wind in enumerate(coil):
        wind.move(np.linspace((0, 0, 0), (0, 0, (2 - i) * 0.001), 15))

# Display as animation
magpy.show(*helmholtz, animation=True, style_path_show=False)
```

--------------------------------

### Verifying convergence with meshing parameters

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_force_intro.html

Test convergence by iterating through different meshing densities to ensure result stability.

```python
# Test multiple mesh densities
meshings = [50, 100, 200]
for m in meshings:
    target.meshing = m
    F, T = magpy.getFT(source, target)
    # Compare results...
```

--------------------------------

### Create a Cuboctahedron Magnet with Triangles

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_shapes_triangle.html

Demonstrates defining a collection of triangles to form a cuboctahedron shape and visualizing it with PyVista.

```python
import magpylib as magpy
import numpy as np

# Create collection of triangles
triangles_cm = [
    ([0, 1, -1], [-1, 1, 0], [1, 1, 0]),
    ([0, 1, 1], [1, 1, 0], [-1, 1, 0]),
    ([0, 1, 1], [-1, 0, 1], [0, -1, 1]),
    ([0, 1, 1], [0, -1, 1], [1, 0, 1]),
    ([0, 1, -1], [1, 0, -1], [0, -1, -1]),
    ([0, 1, -1], [0, -1, -1], [-1, 0, -1]),
    ([0, -1, 1], [-1, -1, 0], [1, -1, 0]),
    ([0, -1, -1], [1, -1, 0], [-1, -1, 0]),
    ([-1, 1, 0], [-1, 0, -1], [-1, 0, 1]),
    ([-1, -1, 0], [-1, 0, 1], [-1, 0, -1]),
    ([1, 1, 0], [1, 0, 1], [1, 0, -1]),
    ([1, -1, 0], [1, 0, -1], [1, 0, 1]),
    ([0, 1, 1], [-1, 1, 0], [-1, 0, 1]),
    ([0, 1, 1], [1, 0, 1], [1, 1, 0]),
    ([0, 1, -1], [-1, 0, -1], [-1, 1, 0]),
    ([0, 1, -1], [1, 1, 0], [1, 0, -1]),
    ([0, -1, -1], [-1, -1, 0], [-1, 0, -1]),
    ([0, -1, -1], [1, 0, -1], [1, -1, 0]),
    ([0, -1, 1], [-1, 0, 1], [-1, -1, 0]),
    ([0, -1, 1], [1, -1, 0], [1, 0, 1]),
]
triangles = np.array(triangles_cm) / 100  # cm -> m
cuboc = magpy.Collection()
for t in triangles:
    cuboc.add(
        magpy.misc.Triangle(
            polarization=(0.1, 0.2, 0.3),
            vertices=t,
        )
    )

# Display collection of triangles
magpy.show(
    cuboc,
    backend="pyvista",
    style_magnetization_mode="arrow",
    style_orientation_color="yellow",
)
```

--------------------------------

### Simulate and Visualize Magnetic Image Method

Source: https://magpylib.readthedocs.io/en/latest/_pages/user_guide/examples/examples_misc_image_method.html

Uses Magpylib to define a magnet and its mirror image, then computes and renders the magnetic field lines using PyVista.

```python
import pyvista as pv
import magpylib as magpy
from scipy.spatial.transform import Rotation as R

# Magnet Parameters
height = 1
angle = 30

# Create a cuboid magnet above the mirror plane
magnet = magpy.magnet.Cylinder(
    polarization=(0, 0, 1),
    dimension=(1, 1),
    position=(0, 0, height),
    orientation=R.from_euler('y', angle, degrees=True)
)

# Create mirror image of the magnet
mirror_magnet = magnet.copy(
    position=(0, 0, -1),  # Mirror position
    orientation=R.from_euler('y', -angle, degrees=True)  # Mirror orientation
)

# Create a 3D grid with Pyvista
grid = pv.ImageData(
    dimensions=(61, 61, 61),
    spacing=(0.1, 0.1, 0.1),
    origin=(-3, -3, 0),
)

# Compute B-field and add as data to grid
col = magnet + mirror_magnet
grid["B"] = col.getB(grid.points)*1000 # Convert to mT

# Compute the field lines
seed = pv.Disc(center=(0, 0, 0), inner=2, outer=3, r_res=1, c_res=12)
strl = grid.streamlines_from_source(
    seed,
    vectors="B",
    max_step_length=0.02,
    integration_direction="backward",
)

# Create a Pyvista plotting scene
pl = pv.Plotter()

# Add magnet to scene - streamlines units in (m)
magpy.show(magnet, canvas=pl, units_length="m", backend="pyvista")

# Prepare legend parameters
legend_args = {
    "title": "B (mT)",
    "title_font_size": 20,
    "color": "black",
    "position_y": 0.25,
    "vertical": True,
}

# Add streamlines and legend to scene
pl.add_mesh(
    strl.tube(radius=0.02),
    cmap="bwr",
    scalar_bar_args=legend_args,
)

# Add mirror to the scene
disc = pv.Disc(center=(0, 0, 0), inner=0.0, outer=4, normal=(0, 0, 1), r_res=1, c_res=100)
pl.add_mesh(disc, color='lightblue', show_edges=False)

# Prepare and show scene
pl.camera.position = (5, 15, 10)
pl.show()
```

--------------------------------

### Configure Magpylib Object Styling

Source: https://magpylib.readthedocs.io/en/latest/_autogen/magpylib.html

Demonstrates setting global and individual object styles for visualization, including path visibility and magnetization representation.

```python
>>> import magpylib as magpy
>>> src1 = magpy.magnet.Sphere(position=[(0, 0, 0), (0, 0, 3)], diameter=1, polarization=(1, 1, 1))
>>> src2 = magpy.magnet.Sphere(
...     position=[(1, 0, 0), (1, 0, 3)],
...     diameter=1,
...     polarization=(1, 1, 1),
...     style_path_show=False
... )
>>> magpy.defaults.display.style.magnet.magnetization.size = 2
>>> src1.style.magnetization.size = 1
>>> magpy.show(src1, src2, style_color='r') 
>>> # graphic output
```
Tokens:
Raw