PicketFence.result_data 'mlc_positions_by_leaf'

[françois xavier Arnaud]

Dear all, 

I'm trying to understand some results available in picketfence.result_data['mlc_positions_by_leaf'] dictionnary.

For example, using an integrated image with 10 pickets

- 'offsets_from_cax_mm': [65.26953901931351, 50.28011012703084, 35.27186791603355, 20.266991623371677, 5.260303567943333, -9.751371576478455, -24.757808639163564, -39.76862481744024, -54.783193605823556, -69.75075800609807],

- 'mlc_positions_by_leaf':  {

[...]

'15': [131.43360342737398, 146.42161475299872, 161.43251387842128, 176.44624194002458, 191.46825779373773, 206.49736620570349, 221.5258751568509, 236.53135100021882, 251.5530831470596, 266.5205398505989],

 '16': [131.47908671525886, 146.4807264723526, 161.4737616589679, 176.49306290128303, 191.49040290413393, 206.48751214912562, 221.4841243604419, 236.5021192599006, 251.53165394985348, 266.4991951454547],

[...]

I understand that maybe my origin is not the same but i'm struggling to understand the kind of distances I got in mlc_positions_by_leaf' {} ? 

For example for leaf15 my first picket position (picket[0]) is  at 131.43360342737398mm but from cax my 'mean" corresponding picket position is  65.26953901931351mm. 

My corresponding last picket position is 266.5205398505989?

Could youi give me some detail to understand it?

My theoretical position from my RTPlan for picket[0] is 65mm. What is thus my corresponding absolute position error for leaf 15, picket[0] ?

Thanks in advance for your help.

François
 

[James Kerns]

The `mlc_positions_by_leaf` are the absolute position, starting from the left of the image (for an Up/down orientation). To determine the distance from the MLC position to the CAX you can do something like:

pf = PicketFence(...)
cax = pf.image.cax/pf.image.dpmm  # physical position

dist = cax - mlc_positions_by_leaf[13][0]  # leaf 13, picket 0

I.e. the positions are absolute. Shift by the CAX position to get the position relative to the CAX.

[françois xavier Arnaud]

Tanks James

We have to do for each picket and each leaf

dist = cax.x - mlc_positions_by_leaf[13][0]

thanks again it's fine