The input list is a list of TObject which is made available at running time on each participating node and in the TSelector object (fInput member). This list is meant to provide a way to provide relevant information for the query and can therefore be used to control the job.
- Adding / Removing objects to / from the input list
- Working with parameters
- Working with large input objects
- List of parameters already used by PROOF
1. Adding / Removing objects to / from the input list
PROOF provides the following API to handle generic input objects:
| void TProof::AddInput(TObject *obj) |
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| Purpose | Provide a hook to add an object to the input list |
| obj | Object to be added; though not mandatory, it is recommended that this object is named, so that it can be easily searched for by name. |
| void TProof::ClearInput() |
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| Purpose | Clear the input list |
| TList *TProof::GetInputList() |
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| Purpose | Get a pointer to the input list |
2. Working with parameters
One of the main usage of the input list is to set parameters for the selector. PROOF provides and interface to automatically add or retrieve TParameter objects to / from the input list:
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void TProof::SetParameter(const char *name, const char *par) void TProof::SetParameter(const char *name, Int_t par) void TProof::SetParameter(const char *name, Long_t par) void TProof::SetParameter(const char *name, Long64_t par) void TProof::SetParameter(const char *name, Double_t par) |
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| Purpose | Provide a way to add named parameters of the specified type |
| name | Name of the parameter |
| par | Value of the parameter |
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TObject *TProof::GetParameter(const char *name) |
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| Purpose | Provide a way to get a named parameter from the input list; the returned object must be cast to the relevant TParameter<...> implementation |
| name | Name of the parameter |
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Int_t TProof::GetParameter(TCollection *c, const char *name, TString &par) Int_t TProof::GetParameter(TCollection *c, const char *name, Int_t &par) Int_t TProof::GetParameter(TCollection *c, const char *name, Long_t &par) Int_t TProof::GetParameter(TCollection *c, const char *name, Long64_t &par) Int_t TProof::GetParameter(TCollection *c, const char *name, Double_t &par) |
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| Purpose | Provide a way to retrieve named parameters of the specified type from a generic collection; these methods are static. |
| name | Name of the parameter |
| par | Value of the parameter |
| Return | 0 on success; -1 on error (parameter not found) |
3. Working with large input objects
When the input objects are large - e.g. TH3 calibration maps - the default way of distributing - i.e. the input list by streaming in the main message - can be very inefficient. PROOF provides an optimized way to distribute these input data constisting in saving these objects into a ROOT file and distributing the file in an optimized way, i.e. compressed, only if any of these objects has changed and only to the unique workers. These objects are available in the nodes via the input list just as the others. The following API is available for theis purpose:
| void TProof::AddInputData(TObject *obj, Bool_t push) |
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| Purpose | Add an object to the input data list |
| obj | Object to be added; though not mandatory, it is recommended that this object is named, so that it can be easily searched for by name. |
| push | If TRUE the input data are sent over even if no apparent change occured to the input data list |
| void TProof::ClearInputData(TObject *obj) |
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| Purpose | Remove object from the input data list |
| obj | Object to be removed; if null, all input data objects are removed |
| void TProof::ClearInputData(const char *name) |
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| Purpose | Remove named object from the input data list |
| name | Name of the object to be removed |
| void TProof::SetInputDataFile(const char *datafile) |
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| Purpose | Set the file to be used to optimally distribute the input data objects. If the file exists the object in the file are added to those in the input data list |
| datafile | Path to the file |