Source code for freegs.test_filament_coil

import numpy as np

from .coil import Coil
from .filament_coil import FilamentCoil
from .machine import Circuit




def test_single():
    """
    Test that a single turn FilamentCoil is the same as a Coil
    """

    fcoil = FilamentCoil(1.1, 0.2, current=100.0)
    coil = Coil(1.1, 0.2, current=100.0)

    assert np.isclose(coil.controlPsi(0.3, 0.1), fcoil.controlPsi(0.3, 0.1))

    assert np.isclose(coil.controlBr(0.3, 0.1), fcoil.controlBr(0.3, 0.1))





def test_two_filaments():
    """
    FilamentCoil with two filaments same as circuit with two coils at half current
    """

    fcoil = FilamentCoil([1.1, 1.2], [0.2, -0.3])

    circuit = Circuit(
        [
            ("A", FilamentCoil(1.1, 0.2), 0.5),
            ("B", FilamentCoil(1.2, -0.3), 0.5),
        ]
    )

    # Check the Greens functions (field produced by unit circuit current)
    assert np.isclose(circuit.controlPsi(0.3, 0.1), fcoil.controlPsi(0.3, 0.1))
    assert np.isclose(circuit.controlBr(0.3, 0.1), fcoil.controlBr(0.3, 0.1))
    assert np.isclose(circuit.controlBz(0.3, 0.1), fcoil.controlBz(0.3, 0.1))

    # Check the field, putting the same current
    fcoil.current = 100
    circuit.current = 100
    assert np.isclose(circuit.psi(0.3, 0.1), fcoil.psi(0.3, 0.1))
    assert np.isclose(circuit.Br(0.3, 0.1), fcoil.Br(0.3, 0.1))
    assert np.isclose(circuit.Bz(0.3, 0.1), fcoil.Bz(0.3, 0.1))





def test_two_turns():
    """
    FilamentCoil with two turns same as circuit with two coils
    """

    fcoil = FilamentCoil(1.1, 1.2, turns=2)

    circuit = Circuit(
        [
            ("A", FilamentCoil(1.1, 1.2), 1.0),
            ("B", FilamentCoil(1.1, 1.2), 1.0),
        ]
    )

    # Check the Greens functions (field produced by unit circuit current)
    assert np.isclose(circuit.controlPsi(0.3, 0.1), fcoil.controlPsi(0.3, 0.1))
    assert np.isclose(circuit.controlBr(0.3, 0.1), fcoil.controlBr(0.3, 0.1))
    assert np.isclose(circuit.controlBz(0.3, 0.1), fcoil.controlBz(0.3, 0.1))





def test_mirrored():
    """
    Mirrored FilamentCoil the same as two coils in a circuit at half current

    Filaments in a FilamentCoil are wired in parallel, not in serial.
    """
    fcoil = FilamentCoil([1.1, 1.1], [0.2, -0.2])

    circuit = Circuit(
        [
            ("A", Coil(1.1, 0.2), 0.5),
            ("B", Coil(1.1, -0.2), 0.5),
        ]
    )

    # Check
    assert np.isclose(circuit.controlPsi(0.3, 0.1), fcoil.controlPsi(0.3, 0.1))
    assert np.isclose(circuit.controlBr(0.3, 0.1), fcoil.controlBr(0.3, 0.1))
    assert np.isclose(circuit.controlBz(0.3, 0.1), fcoil.controlBz(0.3, 0.1))





def test_move_R():
    """
    Changing major radius property R changes all filament locations
    """

    dR = 0.6
    coil1 = FilamentCoil([1.1, 0.2], [1.2, -0.3], current=100.0)
    coil2 = FilamentCoil([1.1 + dR, 0.2 + dR], [1.2, -0.3], current=100.0)

    # Shift coil1 to same location as coil2
    coil1.R += dR

    assert np.isclose(coil1.controlPsi(0.4, 0.5), coil2.controlPsi(0.4, 0.5))

    assert np.isclose(coil1.controlBr(0.3, -0.2), coil2.controlBr(0.3, -0.2))

    assert np.isclose(coil1.controlBz(1.75, 1.2), coil2.controlBz(1.75, 1.2))





def test_move_Z():
    """
    Changing height property Z changes all filament locations
    """

    dZ = 0.4
    coil1 = FilamentCoil([1.1, 0.2], [1.2, -0.3], current=100.0)
    coil2 = FilamentCoil([1.1, 0.2], [1.2 + dZ, -0.3 + dZ], current=100.0)

    # Shift coil1 to same location as coil2
    coil1.Z += dZ

    assert np.isclose(coil1.controlPsi(0.4, 0.5), coil2.controlPsi(0.4, 0.5))

    assert np.isclose(coil1.controlBr(0.3, -0.2), coil2.controlBr(0.3, -0.2))

    assert np.isclose(coil1.controlBz(1.75, 1.2), coil2.controlBz(1.75, 1.2))