...

Environment data include all kinds of data which are not part of the event data. Usually environment data either stay the same for the whole job or change at a slower rate than event data. Example of the environment data could be configuration data read from XTC at the beginning of the job, EPICS data which is not updated on every event, and few other things. Environment data is represented for user code through the object of type pyana.event.Env. Its interface is described in the reference manual.

Data Source Address

For some pieces of data one needs to specify data "address" which identifies (maybe partially) particular DAQ device which produced the data. This is needed because the instrument setup may include multiple devices producing the same data type. The DAQ defines a type which serves as a most specific device identification, the type is xtc.DetInfo in package pypdsdata. One can pass this DetInfo instance to a method which accepts device address to select that specific device. DetInfo object contains four essential pieces of information:

• detector – one of the DetInfo.Detector.* values
• detId – ID number selecting one of multiple detectors
• device – one of the DetInfo.Device.* values
• devId – ID number selecting one of multiple devices
  One can build DetInfo out of these four values, but DetInfo constructor (which mimics C++ behavior) needs also a nuisance processId parameter. In most cases using the address string described below is preferred to manually building DetInfo objects.

In many cases the DetInfo object is not known to the user or the code uses only partial information to identify one or many data sources. In such cases it is easier to use address string as an argument to methods accepting address parameter. The most generic format of address string is:

[detector][-[detId]]["|"[device][-[devId]]]

In words address string is an optional detector name followed by optional dash and detector ID separated by vertical bar from optional device name followed by optional dash and device ID. Detector name and device name are the names defined in DetInfo.Detector and DetInfo.Device enums respectively. Examples of detector names are AmoGasdet, AmoETof, Camp, etc. Examples of device names are Acqiris, pnCCD, Evr, etc. For complete list check the Reference Manual.

Here are few example address strings:

• "AmoETof-0|Acqiris-0" – selects data produced by detector AmoETof, detId 0, device Acqiris, devId 0
• "AmoETof|Acqiris" – selects data produced by detector AmoETof, any detId, device Acqiris, any devId
• "AmoETof-0" – selects data produced by detector AmoETof, detId 0, any device, any devId
• "|Acqiris-0" – selects data produced by any detector, any detId, device Acqiris, devId 0

Configuration

Multi-processing

...