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A quick walk-through of the tools that exist for analysis of xtc files with python.
The main focus is on pyana, and the examples are from and for XPP primarily,
but may be useful examples to other experiments too.

...

Scanning....
Start parsing files:
['/reg/d/psdm/xpp/xppi0310/xtc/e81-r0098-s00-c00.xtc', '/reg/d/psdm/xpp/xppi0310/xtc/e81-r0098-s01-c00.xtc']
  14826 datagrams read in 4.120000 s .   .   .   .   .   .   .
-------------------------------------------------------------
XtcScanner information:
  - 61 calibration cycles.
  - Events per calib cycle:
   [240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240, 240]

Information from  1  control channels found:
fs2:ramp_angsft_target
Information from  11  devices found
                      BldInfo:EBeam:             EBeamBld_V1 (14641)
            BldInfo:FEEGasDetEnergy:             FEEGasDetEnergy (14563)   Any (78)
             BldInfo:NH2-SB1-IPM-01:             SharedIpimb (14641)
                BldInfo:PhaseCavity:             PhaseCavity (14641)
     DetInfo:EpicsArch-0|NoDevice-0:             Epics_V1 (107580)
         DetInfo:NoDetector-0|Evr-0:             EvrConfig_V4 (62)   EvrData_V3 (14640)
        DetInfo:XppSb2Ipm-1|Ipimb-0:             IpimbConfig_V1 (1)   IpmFexConfig_V1 (1)   IpimbData_V1 (14640)   IpmFex_V1 (14640)
        DetInfo:XppSb3Ipm-1|Ipimb-0:             IpimbConfig_V1 (1)   IpmFexConfig_V1 (1)   IpimbData_V1 (14640)   IpmFex_V1 (14640)
        DetInfo:XppSb3Pim-1|Ipimb-0:             IpimbConfig_V1 (1)   IpmFexConfig_V1 (1)   IpimbData_V1 (14640)   IpmFex_V1 (14640)
        DetInfo:XppSb4Pim-1|Ipimb-0:             IpimbConfig_V1 (1)   IpmFexConfig_V1 (1)   IpimbData_V1 (14640)   IpmFex_V1 (14640)
                          ProcInfo::             RunControlConfig_V1 (62)
XtcScanner is done!
-------------------------------------------------------------

xtcexplorer

XTC Explorer - Old - GUI interface that builds pyana modules for you.

...

import h5py

ofile = h5py.File("output_file_name.h5",'w')
group = ofile.create_group("MyGroup")
group.create_dataset('delaytime',data=np.array(self.h_delaytime))
group.create_dataset('rawsignal',data=np.array(self.h_ipm_rsig))
group.create_dataset('normsignal',data=np.array(self.h_ipm_nsig))
ofile.close()

...

Like the other frameworks, pyana is an executable that loops through the XTC file and calls all
requested user modules at certain transitions. All the analysts need to do is to fill in the
relevant functions in their user analysis module:

{toggle-cloak

:id

=kappe}

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For the following two examples, check out the latest version of the pyana_examples package:

...

addpkg pyana_examples HEAD
scons

(Note, if you don't already have a Kerberos ticket, you need to issue a 'kinit' command before 'addpkg'. You will be prompted for your unix password.)

Datatypes, and how to find data from your detector/device in the xtc file.

Pyana and psana has follows this naming scheme for labeling the datatypes from various devices. You can find the
names by investigating the xtc file with the above-mentioned tools (pyxtcreader, xtcscanner, xtcexplorer).
To see some examples of how to fetch the various data types in pyana (or psana), look at Devices and Datatypes.

Point detector delay scan

...

{cloak:id=kappe}

# useful imports
import numpy as np
import matplotlib.pyplot as plt
from pypdsdata.xtc import TypeId

class mymodule (object) :
    """Class whose instance will be used as a user analysis module. """

    def __init__ ( self,
                   source = ""
                   threshold = "" ):
        """Class constructor.
        The parameters to the constructor are passed from pyana configuration file.
        If parameters do not have default values  here then the must be defined in
        pyana.cfg. All parameters are passed as strings, convert to correct type before use.

        @param source         name of device, format 'Det-ID|Dev-ID'
        @param threshold      threshold value (remember to convert from string)
        """
        self.source = source
        self.threshold = float(threshold)

    def beginjob( self, evt, env ) :
        """This method is called once at the beginning of the job. It should
        do a one-time initialization possible extracting values from event
        data (which is a Configure object) or environment.

        @param evt    event data object
        @param env    environment object
        """
        pass

    def beginrun( self, evt, env ) :
        """This optional method is called if present at the beginning of the new run.

        @param evt    event data object
        @param env    environment object
        """
        pass

    def begincalibcycle( self, evt, env ) :
        """This optional method is called if present at the beginning
        of the new calibration cycle.

        @param evt    event data object
        @param env    environment object
        """
        pass

    def event( self, evt, env ) :
        """This method is called for every L1Accept transition.

        @param evt    event data object
        @param env    environment object
        """
        pass

    def endcalibcycle( self, env ) :
        """This optional method is called if present at the end of the
        calibration cycle.

        @param env    environment object
        """
        pass

    def endrun( self, env ) :
        """This optional method is called if present at the end of the run.

        @param env    environment object
        """
        pass

    def endjob( self, env ) :
        """This method is called at the end of the job. It should do
        final cleanup, e.g. close all open files.

        @param env    environment object
        """
        pass

{cloak}

addpkg pyana_examples HEAD
scons

Datatypes, and how to find data from your detector/device in the xtc file.

Pyana and psana has follows this naming scheme for labeling the datatypes from various devices. You can find the
names by investigating the xtc file with the above-mentioned tools (pyxtcreader, xtcscanner, xtcexplorer).
To see some examples of how to fetch the various data types in pyana (or psana), look at Devices and Datatypes.

Point detector delay scan

The python code for this pyana module resides in pyana_examples/src/xppt_delayscan.py.  In this example, we do a point detector delay scan, where we get the time as scan points via a control PV, and where time rebinning based on phase cavity measurement is used to improve the time resolution. One IPIMB device (a.k.a. IPM3) is used for normalization (i0, I Zero) (parameter name ipimb_norm) and another IPIMB device (a.k.a. PIM3) channel 1 is used as the signal (parameter name ipimb_sig).

[pyana]

modules = pyana_examples.xppt_delayscan

[pyana_examples.xppt_delayscan]
controlpv = fs2:ramp_angsft_target
ipimb_norm = XppSb3Ipm-1|Ipimb-0
ipimb_sig = XppSb3Pim-1|Ipimb-0
threshold = 0.1
outputfile = point_scan_delay.npy

pyana -n 200 /reg/d/psdm/XPP/xppi0310/xtc/e81-r0098-s0*

{toggle-cloak:id=delayscan}

{cloak:id=delayscan}

• Fetching the ControlPV information:
  ControlPV is available from the env object, and since it only changes at the beginning
  of each calibration cycle, the begincalibcycle function is the appropriate place to get it:
  

  Code Block
  none none
  def begincalibcycle( self, evt, env ) :

  
  The ControlConfig object may contain several pvControl and pvMonitor objects. In this case
  there's only one, but make sure the name matches anyway:

  Code Block
  none none
  ctrl_config = env.getConfig(TypeId.Type.Id_ControlConfig) for ic in range (0, ctrl_config.npvControls() ): cpv = ctrl_config.pvControl(ic) if cpv.name()=="fs2:ramp_angsft_target": # store the value in a class variable (visible in every class method) self.current_pv_value = cpv.value() )

• Fetching the IPIMB and PhaseCavity information:
  All the other information that we need, is available through the evt object, and
  event member function is the place to get it:
  

  Code Block
  none none
  def event( self, evt, env ) :

  
  Use "XppSb3Ipm-1|Ipimb-0" (a.k.a. IPM3) sum of all channels for normalization and filtering
  

  Code Block
  none none
  ipmN_raw = evt.get(TypeId.Type.Id_IpimbData, "XppSb3Ipm-1|Ipimb-0") ipmN_fex = evt.get(TypeId.Type.Id_IpmFex, "XppSb3Ipm-1|Ipimb-0") ipmN_norm = ipmN_fex.sum

  
  Use "XppSb3Pim-1|Ipimb-0" (a.k.a. PIM3) channel 1

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• as

...

• signal

...

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Open an editor and save the following in a file named pyana.cfg:

• Code Block
  none none

...

[pyana]

modules = pyana_examples.xppt_delayscan

[pyana_examples.xppt_delayscan]
controlpv = fs2:ramp_angsft_target
ipimb_norm = XppSb3Ipm-1|Ipimb-0
ipimb_sig = XppSb3Pim-1|Ipimb-0
threshold = 0.1
outputfile = point_scan_delay.npy

...

• ipmS_raw = evt.get(TypeId.Type.Id_IpimbData, "XppSb3Pim-1|Ipimb-0"

...

• ) ipmS_fex = evt.get(TypeId.Type.Id_IpmFex, "XppSb3Pim-1|Ipimb-0"

...

Run pyana (start with 200 events):

• ) ipm_sig = ipmS_fex.channel[1]

  
  Get the phase cavity:
  

  Code Block
  none none
  pc = evt.getPhaseCavity() phasecav1 = pc.fFitTime1 phasecav2 = pc.fFitTime2 charge1 = pc.fCharge1 charge2 = pc.fCharge2

  
  Compute delay time and fill histograms
  

  Code Block
  none none
  delaytime = self.current_pv_value + phasecav1*1e3 # The "histograms" are nothing but python lists. Append to them, and turn them into arrays at the end. self.h_ipm_rsig.append( ipm_sig ) self.h_ipm_nsig.append( ipm_sig/ipm_norm ) self.h_delaytime.append( delaytime )

{cloak}

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pyana -n 200 /reg/d/psdm/XPP/xppi0310/xtc/e81-r0098-s0*

Image peak finding

Here are a collection of useful algorithms for image analysis: http://docs.scipy.org/doc/scipy/reference/ndimage.html

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