Fix for larger errorst in first/last bpms (thx Andreas) (#430)

* Fix for larger errorst in first/last bpms (thx Andreas)

* version bump and changelog update

---------

Co-authored-by: awegsche <[email protected]>

Author: fscarlier

CHANGELOG.md

@@ -1,5 +1,9 @@
 # OMC3 Changelog
 
+#### 2023-09-20 - v0.11.3 - _fscarlier_, _awegsche_
+- Fixed:
+    - bug in beta from phase (3BPM method) that calculated too high errors for first and last BPMs
+
 #### 2023-09-20 - v0.11.3 - _jdilly_, _awegsche_
 
 - Fixed:

omc3/__init__.py

@@ -11,7 +11,7 @@
 __title__ = "omc3"
 __description__ = "An accelerator physics tools package for the OMC team at CERN."
 __url__ = "https://github.com/pylhc/omc3"
-__version__ = "0.11.3"
+__version__ = "0.11.4"
 __author__ = "pylhc"
 __author_email__ = "[email protected]"
 __license__ = "MIT"

omc3/optics_measurements/beta_from_phase.py

@@ -87,7 +87,7 @@ def n_bpm_method(meas_input, phase, plane, meas_and_mdl_tunes):
                         "were requested in N-BPM method. Using all available BPMs instead,"
                         "the results will still be correct.")
         n_bpms = n_bpms_phases
-    
+
     if n_bpms < 3:
         raise ValueError("At least 3 BPMs are required for N-BPM method!"
                         f"Instead a range of {n_bpms} was requested.")
@@ -422,7 +422,7 @@ def three_bpm_method(meas_input, phase, plane, meas_and_mdl_tunes):
     # tilt phase advances in order to have the phase advances in a neighbourhood
     tilted_meas = _tilt_slice_matrix(phase["MEAS"].to_numpy(), 2, 5, tune) * PI2
     tilted_model = _tilt_slice_matrix(phase["MODEL"].to_numpy(), 2, 5, mdltune) * PI2
-    tilted_errmeas = _tilt_slice_matrix(phase["ERRMEAS"].to_numpy(), 2, 5, mdltune) * PI2
+    tilted_errmeas = _tilt_slice_matrix(phase["ERRMEAS"].to_numpy(), 2, 5, 0) * PI2
     betmdl = beta_df.loc[:, f"BET{plane}{MDL}"].to_numpy()
     alfmdl = beta_df.loc[:, f"ALF{plane}{MDL}"].to_numpy()
     with np.errstate(divide='ignore'):