Matt, Hang

We ran the a2l decoupling optimization code this evening for all test masses and for both pitch and yaw. It successfully reduced the low frequency noise. Please see the attachment (darm_spectrum.png). 

The changes were:
H1:SUS-ETMX_L2_DRIVEALIGN_P2L_GAIN: 0.93 -> 1.21
H1:SUS-ETMX_L2_DRIVEALIGN_Y2L_GAIN: 0.93 -> 1.32
H1:SUS-ETMY_L2_DRIVEALIGN_P2L_GAIN: 0.00 -> -0.02
H1:SUS-ETMY_L2_DRIVEALIGN_Y2L_GAIN: -0.70 -> -0.59
H1:SUS-ITMX_L2_DRIVEALIGN_P2L_GAIN: 1.95 -> 2.04
H1:SUS-ITMX_L2_DRIVEALIGN_Y2L_GAIN: 0.63 -> 0.74
H1:SUS-ITMY_L2_DRIVEALIGN_P2L_GAIN: 1.05 -> 1.06
H1:SUS-ITMY_L2_DRIVEALIGN_Y2L_GAIN: -2.05 -> -1.48

H1:SUS-ETMX_L2_DRIVEALIGN_P2L_GAIN 
More details of the measurements could be found under:
/opt/rtcds/userapps/trunk/isc/h1/scripts/a2l/rec. 
It contained both the raw measured data (I, Q and total), and plots of our linear fits as well as rotation. The optimal a2l gains corresponded to the zeros of rotated I's. Please again note that since our data were likely to be correlated, the errorbars shown should just be treated as a rough estimation.

=================================================================================================================================================================================

Besides, we also wrapped the python code into a bash shell that could be easily called in the future. It could be found under:
/opt/rtcds/userapps/trunk/isc/h1/scripts/a2l

To rerun the optimization, you can simply enter
./run_a2l.sh
in the command line, and the code will do the optimization for all test masses and all angular dofs. 

If you just want to optimize some specific optics and, say, only their pitch to length coupling, you can just edit the 'a2l_input.in' file.

In cases that the interferometer loses lock, please press "ctrl + c" to terminate the code. With this keyboard interruption, it will automatically set the not yet optimized drive align gains back to their original values and disable the dither input. 

For more instructions, please refer to 'readme.txt' under the same directory.