test_ligo_quad¶

tests.quad_damping.test_ligo_quad

Unit tests and examples for damping the LIGO QUAD suspensions

Provided by Kevin Kuns

Functions

`test_convert_zpk_ss`()	Converts a LIGO damping filter from ZPK to statespace and back to test numerical stability
`test_damp_quad`(quad_type)	Damp the undamped LIGO QUAD state space model

Details

test_convert_zpk_ss()[source]¶

Converts a LIGO damping filter from ZPK to statespace and back to test numerical stability

code

docstring

"""
Converts a LIGO damping filter from ZPK to statespace and back to test numerical stability
"""

def test_convert_zpk_ss():

    fname = fjoin('damping_filters.h5')
    zpk = load(fname).L
    dprint('testing!')
    filt_zpk = SISO.zpk(zpk.z, zpk.p, zpk.k)
    filt_ss = filt_zpk.asSS
    filt_zpk2 = filt_ss.asZPK

    # TODO - no reason to think these sets are sorted the same way for a direct comparison
    dprint(np.allclose(filt_zpk.z, filt_zpk2.z))
    # TODO - no reason to think these sets are sorted the same way for a direct comparison
    dprint(np.allclose(filt_zpk.p, filt_zpk2.p))
    # this should be True
    dprint(np.isclose(filt_zpk.k, filt_zpk2.k))

pytest information

This code is wrapped in a pytest function using conventions detailed in Pytest Conventions. The full name of this test, as known by the documentation, is:

tests.quad_damping.test_ligo_quad.test_convert_zpk_ss

The full name is useful when building documentation, to link a reference to this page using :func:`name`, or directly include it with an autofunction directive. The collapse nodes below show every instance of the test run. There may only be one, but if the test was run multiple times through pytest parametrizations, the list can be longer.

test_convert_zpk_ss

output

status: passed
duration: 0.094s
Captured stderr call
'testing!'
False
False
True

capture.txt

test_damp_quad(quad_type)[source]¶

Damp the undamped LIGO QUAD state space model

Tests calculation of frequency responses and conversion of the resulting damped state space plant to ZPK

code

docstring

"""
Damp the undamped LIGO QUAD state space model

Tests calculation of frequency responses and conversion of the resulting damped state space
plant to ZPK
"""

@pytest.mark.parametrize('quad_type', ['quad_full', 'quad_small'])
def test_damp_quad(quad_type):

    # load quad state space
    ss_data = load(fjoin(quad_type + '.h5'))
    udamp_plant = MIMO.MIMOStateSpace(
        ss_data.A, ss_data.B, ss_data.C, ss_data.D,
        inputs=dict(ss_data.inputs), outputs=dict(ss_data.outputs),
    )

    # load ZPK damping filters and convert to state space
    zpk_data = load(fjoin('damping_filters.h5'))
    damp_filts = Bunch()
    for dof, zpk in zpk_data.items():
        damp_filts[dof] = SISO.zpk(zpk.z, zpk.p, zpk.k).asSS

    # Need to make the SISO damping filters into 1-1 MIMO filters with specified
    # inputs and outputs for making the feedback connections
    damp_plant = MIMO.ssjoinsum(
        udamp_plant,
        damp_filts.L.mimo('M0.L.o', 'M0.L.i'),
        damp_filts.T.mimo('M0.T.o', 'M0.T.i'),
        damp_filts.V.mimo('M0.V.o', 'M0.V.i'),
        damp_filts.P.mimo('M0.P.o', 'M0.P.i'),
        damp_filts.Y.mimo('M0.Y.o', 'M0.Y.i'),
        damp_filts.R.mimo('M0.R.o', 'M0.R.i'),
    )
    # connect the displacements to the inputs to the damping filters
    # and then connect the outputs from the filters to the drives
    connections = [
        ('M0.L.i', 'M0.disp.L'), ('M0.drive.L', 'M0.L.o'),
        ('M0.T.i', 'M0.disp.T'), ('M0.drive.T', 'M0.T.o'),
        ('M0.V.i', 'M0.disp.V'), ('M0.drive.V', 'M0.V.o'),
        ('M0.P.i', 'M0.disp.P'), ('M0.drive.P', 'M0.P.o'),
        ('M0.Y.i', 'M0.disp.Y'), ('M0.drive.Y', 'M0.Y.o'),
        ('M0.R.i', 'M0.disp.R'), ('M0.drive.R', 'M0.R.o'),
    ]
    # make the feedback and balance for numerical stability
    damp_plant = damp_plant.feedback_connect(connections=connections)
    udamp_plant = udamp_plant.balance()
    damp_plant = damp_plant.balance()

    # plot some transfer functions
    F_Hz = np.geomspace(0.05, 10, 1000)
    dprint('Calculating undamped L3')
    udamp_fresp_L3 = udamp_plant.siso('L3.disp.L', 'L3.drive.L').fresponse(f=F_Hz).tf
    dprint('Calculating damped L3')
    damp_fresp_L3 = damp_plant.siso('L3.disp.L', 'L3.drive.L').fresponse(f=F_Hz).tf
    dprint('Calculating undamped M0')
    udamp_fresp_M0 = udamp_plant.siso('M0.disp.L', 'M0.drive.L').fresponse(f=F_Hz).tf
    dprint('Calculating damped M0')
    damp_fresp_M0 = damp_plant.siso('M0.disp.L', 'M0.drive.L').fresponse(f=F_Hz).tf

    fig = plotTF(F_Hz, udamp_fresp_L3, label='Undamped')
    plotTF(F_Hz, damp_fresp_L3, *fig.axes, label='Damped', ls='--')
    fig.axes[0].legend()
    fig.axes[0].set_title('L3 to L3')
    fig.savefig(tjoin('L3.pdf'))

    fig = plotTF(F_Hz, udamp_fresp_M0, label='Undamped')
    plotTF(F_Hz, damp_fresp_M0, *fig.axes, label='Damped', ls='--')
    fig.axes[0].legend()
    fig.axes[0].set_title('M0 to M0')
    fig.savefig(tjoin('M0.pdf'))

    # make zpk filters and convert back to SS
    for (to, fr) in zip(['L3.disp.L', 'M0.disp.L'], ['L3.drive.L', 'M0.drive.L']):
        siso_udamp = damp_plant.siso(to, fr)
        siso_damp = udamp_plant.siso(to, fr)
        zpk_udamp = siso_udamp.asZPK
        zpk_damp = siso_damp.asZPK
        zpk_udamp.asSS
        zpk_damp.asSS

pytest information

This code is wrapped in a pytest function using conventions detailed in Pytest Conventions. The full name of this test, as known by the documentation, is:

tests.quad_damping.test_ligo_quad.test_damp_quad

test_damp_quad[quad_full]

output

status: passed
duration: 275.147s
Captured stderr call
'Calculating undamped L3'
'Calculating damped L3'
'Calculating undamped M0'
'Calculating damped M0'

test_damp_quad[quad_small]

output

status: passed
duration: 2.907s
Captured stderr call
'Calculating undamped L3'
'Calculating damped L3'
'Calculating undamped M0'
'Calculating damped M0'