Project

General

Profile

sorbit-signs.txt

Kyle Hazelwood, 01/15/2015 12:00 PM

 
1
*+ 10/17/2013 sorbit signs of positions and deltacorrectors
2
                      and corrector/bpm orientations 
3

    
4
Call LSSOL to compute correction angles:
5
 sorbit_ls_lssol(int ncorrectors, int npositions,
6
  float *betacorrectors, float *betapositions,
7
  float *phasecorrectors, float *phasepositions, float tune,
8
  float stepcut, float *positions, float *lbcorrectors, float *ubcorrectors,
9
  float *deltacorrectors, float *predictedpositions, int *lssol_inform)
10

    
11
After deltacorrectors found multiply by stepcut and change sign of angles 
12
		(change sign because have solved for angles which move
13
		 the orbit from 0 to the positions inputed and we want
14
		 the angles which move the beam from the positions inputed
15
		 to 0)
16
    stepcutl = -stepcut;
17
    for(ii=0;ii<ncorrectors;ii++)
18
	{
19
	deltacorrectors[ii] = stepcutl*x[ii];
20
	}
21

    
22
The input positions are number of dx mm to be corrected to 0. 
23
After above sign change on deltacorrectors the deltacorrectors should have right
24
sign of correction angles.
25

    
26
If the input positions flip sign(as in my code pre_bpm:
27

    
28
 for (i = 0; i < num_bpms[pl]; i++) cor->dx1[i] = -cor->o1.mm[i];
29

    
30
  /* the sign of correction is as such: -1 is to correct 1 mm distortion */
31

    
32
 if (pgm.i4[I_DESO]) {
33
    for (i = 0; i < num_bpms[pl]; i++) cor->dx1[i] += cor->deso.mm[i];
34
  }
35

    
36
The signs of the above output correction angles must be reversed. 
37
Fact that for recycler  in pa4196(original pa1850) 'sorbit' output deltacorrectors
38
sign reversed only in horz plane indicate corrector/bpm orientations in horz
39
is 'norm' whereas vertical is opposite.
40

    
41
 - float		signs[2] = {-1,1.};
42
 - for (i = 0; i < num_ob_ceds[pl]; i++) cor->dthet[i] *= signs[pl];
43

    
44
IN MI signs[2] = {1,-1.}  indicate corrector/bpm orientations in vertical plane
45
is 'norm' whereas in horz plane is wrong.