Control matrix
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Computing Control Modes
Before proceeding to this step, make sure the required input files are ready:
conf/RMmodesDM/RMmodesDM.fits (response matrix, DM space) conf/RMmodesWFS/RMmodesWFS.fits (response matrix, WFS space) conf/dmmask.fits (DM pixel mask, indicating which actuators are linearly coupled to WFS) conf/wfsmask.fits (WFS pixel mask, indicating which WFS pixels are linearly coupled to DM)
Computing CMs by SVD
Control modes are computed and their representation in both WFS and DM spaces. First, set the SVD limit:
cacao-fpsctrl setval compstrCM svdlim 0.001
Then run the cacao-aorun-039-compstrCM script to compute CM and load it to shared memory:
cacao-aorun-039-compstrCM
Inspect result:
conf/CMmodesDM/CMmodesDM.fits conf/CMmodesWFS/CMmodesWFS.fits Check especially the number of modes controlled.
Conventions:
Control modes are orthogonal in WFS space (dot product between two modes = 0) over the WFS pixel mask (wfsmask)
Control modes are of unity norm in DM space over the DM pixel mask (dmmask)
WFS-space orthogonality ensures that the modal coefficients can be obtained by matrix-vector multiplication (MVM) between CMmodesWFS and the input WFS signal. DM-space normalization ensures that the modal coefficients obtained by the above MVM operation have a physical meaning (unit = micron RMS over dmmask).
Control modes are orthogonal in WFS space (dot product between two modes = 0) over the WFS pixel mask (wfsmask)
Control modes are of unity norm in DM space over the DM pixel mask (dmmask)
WFS-space orthogonality ensures that the modal coefficients can be obtained by matrix-vector multiplication (MVM) between CMmodesWFS and the input WFS signal. DM-space normalization ensures that the modal coefficients obtained by the above MVM operation have a physical meaning (unit = micron RMS over dmmask).
Ordering CMs by Spatial Frequency
The SVD-based process orders modes by singular value, such that DM patterns creating the strongest linear WFS response are first. Ordering CMs by spatial frequency (low-order modes first) is often preferable when implementing and tuning modal control.
# Input:
# ./conf/RMmodesWFS/zrespM-H.fits
# - conf/dmmask.fits
# - conf/wfsmask.fits
#
# Output:
# - conf/CMmodesDM/CMmodesDM_sf.fits
# - conf/CMmodesWFS/CMmodesWFS_sf.fits
#
cacao-aorun-040-compfCM -g 0 -c 25
The cacao-aorun-040-compfCM script allows for much customization. Check options with -h. For a more detailed discussion about how to optimize control modes, check the link.