4 implement magnet hardware link by gupichon · Pull Request #25 · python-accelerator-middle-layer/pyaml

gupichon · 2025-10-01T08:58:04Z

Implementation of an identity model to access to hardware and/or physics values in the control system.

…system

…. First tests but not complete yet.

JeanLucPons · 2025-10-01T09:21:16Z

Thanks for the PR.

Regarding this code, it seems that there is a misunderstanding.

    def compute_hardware_values(self, strengths: np.array) -> np.array:
        raise PyAMLException("The identity model does not support computation")

    def compute_strengths(self, currents: np.array) -> np.array:
        raise PyAMLException("The identity model does not support computation")

When working in hardware units, to work with a simulator, you need a conversion model so when using an identity model it is not possible to compute_strengths(). But when working in physic units, then access to the simulator is possible as no conversion is required.

I do not see the point of the identity_cfm_model module. If your control system provides access to strength, a combined function magnet is necessarily already split into several single function magnets, so the simple identity model applies.

gupichon · 2025-10-01T11:19:57Z

Thanks @JeanLucPons for the review. The simulator access is indeed handled via the get/set methods. The compute methods are only intended to delegate to a conversion model when one exists, which is not the case for an identity model.

gupichon · 2025-10-01T11:21:35Z

The identity_cfm_model is clearly not mandatory but I think it's more user friendly to have it.

JeanLucPons · 2025-10-01T11:42:53Z

Thanks @JeanLucPons for the review. The simulator access is indeed handled via the get/set methods. The compute methods are only intended to delegate to a conversion model when one exists, which is not the case for an identity model.

Not only. The compute_strengths() is used if you want to use aggregator.
Working in hardware units on a control system that handle strengths is possible and means that hardware units are in fact strengths.
This is tricky and this is the purpose of the identity model.
Theoretically, an identity model should just map strength to hardware.
However to make the configuration clearer for the user and to know if link to the simulator is possible or not, we use 2 configuration fields: physics and hardware (or powerconverter).
So in our case:

If the powerconverted is defined, no link to simulator.
If the physics field is defined link to simulator is possible.
In any case, make 1 to 1 relationship strength<->hardware.

This is just a matter to implement correctly compute_hardware_values() and compute_strengths() in function of defined fields.

JeanLucPons · 2025-10-01T14:06:32Z

In the identity model, I expect that either a power supply or a magnet device (physics) is specified but not both.

Mapping strengh:

type: pyaml.magnet.quadrupole
name: QF1A-C01
model:
  type: pyaml.magnet.identity_model
  unit: 1/m
  physics:
    type: tango.pyaml.attribute
    attribute: srmag/m-qf1/c05-a/strength

# 2 following lines are equivalent
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010)
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(0.000010)

# 2 following lines are equivalent
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010)
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(0.000010)

print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").strength.unit()) # 1/m
print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").hardware.unit()) # 1/m

Mapping current (no access to simulator):

type: pyaml.magnet.quadrupole
name: QF1A-C01
model:
  type: pyaml.magnet.identity_model
  unit: A
  powerconverter:
    type: tango.pyaml.attribute
    attribute: srmag/vps-qf1/c05-a/current

sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010) # throw an exception
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(82) #  throw an exception

sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010) # throw an exception
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(82) # Write 82A

print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").strength.unit()) #  throw an exception
print(sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").hardware.unit()) # A

gupichon · 2025-10-02T08:19:54Z

I'll turn your example into a test.

gupichon · 2025-10-06T09:29:10Z

@JeanLucPons, I'm coming back to you about the identity_cfm_model. It is actually necessary to address the element in the design, as there will be only one thick element in the lattice.
By the way, this also raises the question of how sub-elements should be retrieved. For example, if I have a multipole that contains a sextupole and correctors, will the correctors be found with a command like:

sr.live.get_magnets(MagnetType.HCorrector)`

Note that this last point should be addressed in a new issue if a change is needed.

JeanLucPons · 2025-10-06T11:52:04Z

I'm not sure to fully understand.

For an arrays, the type is defined in the config file.
If you want an array of HCORR and SEXT coming from a single element (combined function magnet), you can have:

    arrays:
      - type: pyaml.arrays.hcorrector
        name: HCORR
        elements:
          - SD1A-C01-H
          - SD1A-C02-H
      - type: pyaml.arrays.sextupole
        name: SEXT
        elements:
          - SD1A-C01-S
          - SD1A-C02-S
   devices:
      type: pyaml.magnet.cfm_magnet
      name: SD1A-C01        #Name of the element in the lattice
      mapping:
        - [B0, SD1A-C01-H]
        - [A0, SD1A-C01-V]
        - [B2, SD1A-C01-S]
      model: 
         ...
      type: pyaml.magnet.cfm_magnet
      name: SD1A-C02        #Name of the element in the lattice
      mapping:
        - [B0, SD1A-C02-H]
        - [A0, SD1A-C02-V]
        - [B2, SD1A-C02-S]
      model: 
         ...

    sr.design.get_magnets("HCORR").strengths.set([0.000010,-0.000008])
    sr.design.get_magnets("SEXT").strengths.set([-14.103,-14.107])

If you want to use an identity model, it means that either:
-your control system supports strength
-each multipole are well separated
In that case:

    arrays:
      - type: pyaml.arrays.hcorrector
        name: HCORR
        elements:
          - SD1A-C01
          - SD1A-C02
      - type: pyaml.arrays.sextupole
        name: SEXT
        elements:
          - SD1A-C01
          - SD1A-C02
   devices:
      type: pyaml.magnet.hcorrector
      name: SD1A-C01        #Name of the element in the lattice
      model:
        type: pyaml.magnet.identity_model
        physics:
          type: tango.pyaml.attribute
          attribute: srmag/m-sd1a/c01-a/h_strength
      type: pyaml.magnet.sextupole
      name: SD1A-C01        #Name of the element in the lattice
      model:
        type: pyaml.magnet.identity_model
        physics:
          type: tango.pyaml.attribute
          attribute: srmag/m-sd1a/c01-a/strength
      type: pyaml.magnet.hcorrector
      name: SD1A-C02        #Name of the element in the lattice
      model:
        type: pyaml.magnet.identity_model
        physics:
          type: tango.pyaml.attribute
          attribute: srmag/m-sd1a/c02-a/h_strength
      type: pyaml.magnet.sextupole
      name: SD1A-C02        #Name of the element in the lattice
      model:
        type: pyaml.magnet.identity_model
        physics:
          type: tango.pyaml.attribute
          attribute: srmag/m-sd1a/c02-a/strength

Important: In the config file the element name is not unique. It is the couple type,name (i.e. HCorrector,SD1A-C01) which is unique.

gupichon · 2025-10-06T12:22:35Z

@JeanLucPons, ok the file will be a bit long, but that's fine.

JeanLucPons · 2025-10-06T12:29:39Z

In order to reduce the number of line, you can implement an identity_cfm_model as below:

devices:
      type: pyaml.magnet.cfm_magnet
      name: SD1A-C01        #Name of the element in the lattice
      mapping:
        - [B0, SD1A-C01-H]
        - [A0, SD1A-C01-V]
        - [B2, SD1A-C01-S]
     model: 
       type: pyaml.magnet.identity_cfm_model
       physics:
          - type: tango.pyaml.attribute
            attribute: srmag/m-sd1a/c01-a/h_strength
          - type: tango.pyaml.attribute
            attribute: srmag/m-sd1a/c01-a/v_strength
          - type: tango.pyaml.attribute
            attribute: srmag/m-sd1a/c01-a/strength

gupichon · 2025-10-06T12:45:42Z

@JeanLucPons your last proposal (with a cfm_magnet) seems clearer to me, but I’ll create another issue for that so others can discuss it. Moreover, at SOLEIL, some correctors will be driven by a kick angle, which will imply further changes if i'm correct.

JeanLucPons · 2025-10-06T12:59:50Z

To be coherent, the strength of a dipole should be without unit.
Unit should be 1, 1/m, 1/m^2, 1/m^3, etc...
If you want to convert dipole to angle it should be done outside but as AT can accept angle, this will require some mods to handle PolynomA/B[0] differently in order to map to KickAngle.

gupichon · 2025-10-06T13:37:57Z

I’ll create the corresponding issues.
Regarding the behavior you described in your previous comment, I need to validate it first with @gubaidulinvadim and @GamelinAl.

In the identity model, I expect that either a power supply or a magnet device (physics) is specified but not both.

Mapping strengh:

type: pyaml.magnet.quadrupole
name: QF1A-C01
model:
  type: pyaml.magnet.identity_model
  unit: 1/m
  physics:
    type: tango.pyaml.attribute
    attribute: srmag/m-qf1/c05-a/strength

# 2 following lines are equivalent
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010)
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(0.000010)

# 2 following lines are equivalent
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010)
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(0.000010)

print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").strength.unit()) # 1/m
print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").hardware.unit()) # 1/m

Mapping current (no access to simulator):

type: pyaml.magnet.quadrupole
name: QF1A-C01
model:
  type: pyaml.magnet.identity_model
  unit: A
  powerconverter:
    type: tango.pyaml.attribute
    attribute: srmag/vps-qf1/c05-a/current

sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010) # throw an exception
sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(82) #  throw an exception

sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").strength.set(0.000010) # throw an exception
sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1A-C01").hardware.set(82) # Write 82A

print(sr.design.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").strength.unit()) #  throw an exception
print(sr.live.get_magnet(MagnetType.QUADRUPOLE,"QF1E-C04").hardware.unit()) # A

GamelinAl · 2025-10-06T14:59:07Z

@JeanLucPons it's fine to work with PolynomA/B[0] for correctors. I'll make the change in our test lattice but we might want to support this feature in the future as it is a AT/pyAT feature.

gupichon-soleil added 3 commits September 26, 2025 17:04

First implementation for direct access to hardware values in control …

feaee38

…system

Implementation for direct access to hardware values in control system…

530b614

…. First tests but not complete yet.

Test for identity model with a computation outside pyaml.

7f82a9e

gupichon requested a review from JeanLucPons October 1, 2025 08:58

gupichon linked an issue Oct 1, 2025 that may be closed by this pull request

Implement magnet hardware link #4

Closed

New tests. For now, they don't end well...

3fb4ed0

JeanLucPons added 2 commits October 9, 2025 17:39

Mods for identity magnet models

88374c8

Typo

126032e

JeanLucPons approved these changes Oct 10, 2025

View reviewed changes

JeanLucPons merged commit 45d94d2 into main Oct 10, 2025
2 checks passed

gupichon deleted the 4-implement-magnet-hardware-link branch October 10, 2025 08:41

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