intelligent (or not completely stupid) unpacking

NATIONAL ENERGY RESEARCH SCIENTIFIC COMPUTING CENTER

1C. Leggett <CGLeggett@ lbl.gov>

Intelligent Intelligent (or not completely stupid)(or not completely stupid)

Unpacking Unpacking

Structure and Timing Studies of the Level 3

Calorimeter Unpacking Tool

l3tCalUnpl3tCalUnp



Calorimeter UnpackerCalorimeter UnpackerL3TCalUnpL3TCalUnp

• Level 3 unpacking tool.

• Selectively unpacks sections of the calorimeter according

to input directives:

– Level 1 & 2 seed towers

– Entire calorimeter

– By region

– Size of neighborhood to unpack

– Energy thresholds

– Hot cell flagging thresholds



Low Level StructureLow Level Structure

• The calorimeter unpacker will share many low level unpacking routines with other subdetectors.

• Reads in RawDataChunks, and accesses them on a per-module (ADC card) basis, which is the granularity of the unpacker. This means that if you ask for 1 channel in a module, the unpacker will unpack all 384 channel, reducing the time to access other channels in the same module.

• No method for getting the L2 trigger seed tower information exists, so artificially creates seed towers according to various RCP flags.



Data StructureData Structure

• static float CalUnpData[Neta][Nphi][Nlayer]• Neta = 74

• Nphi = 64

• Nlayer = 18

– array of cell energies and towers (layer = 0)

• static vector<float *> CalUnpEt

– pointers to CalUnpData[eta][phi][0] towers

– for new towers with energy deposits

• various helper routines to access position information, hotcells, to go between array indices, array addresses, and physics indices, etc



Memory RequirementsMemory Requirements

• CalUnpData: 85248 entries = 333.0 kB• only 47456 valid cell addresses

• CalUnpEt: ~18kB (10 % calorimeter occupancy)

• various other internal data: ~10kB

• memory is allocated at beginning of run, and reused. Very

little dynamic memory allocation occurs.

• Big, with lots of empty space.



Initial Setup : Initial Setup : MakeMe()MakeMe()

• Initialize CalUnpData, and other variables

• Reserve space for all stl objects

• Calculate and fill lookup tables

• Queries run_config_mgr to determine hardware configuration, then builds translation tables between (moduleID, crateID) and (crate number, slot number)

• Load CalGainTable



Unpacking Procedure : Unpacking Procedure : DoThisTool(---)DoThisTool(---)

• The DoThisTool() method has been overloaded, so as to tell the unpacker which regions of the calorimeter are to be unpacked. It will currently take:

• DoThisTool()• DoThisTool(vector<TowerAddress> &TA)• DoThisTool(vector<TriggerTowerAddress> &TTA)• DoThisTool(vector<short> &eta,

vector<short>&phi)• DoThisTool(vector<float> &eta,

vector<float>&phi)• DoThisTool(L3Region &)• DoThisTool(L2Seeds &)



Unpacking Procedure : Unpacking Procedure : DoThisTool()DoThisTool()

• Reset vector of CalUnpEt

• Loop over requested seed towers

– Identify neighbors (radius n), form list of towers to unpack

• Loop over selected towers

– Identify associated module(s) (ADC card)

• If the module is not already unpacked, unpack it into CalUnpData

– For all cells in module, calculate energy if has non-zero ADC count

• Add current tower to list of populated towers

• For all newly populated towers, calculate tower energy,

place in layer 0 of CalUnpData



Unpacking Procedure : Whole CalorimeterUnpacking Procedure : Whole Calorimeter

• Reset CalUnpEt• Get all modules in the calorimeter

• Hopefully, this type of unpacking will be called after directed unpacking has already occurred

• Loop over all (new) modules– For each cell, calculate energy

– Set flag showing tower has energy deposits

• For all (new) towers with energy deposits, calculate tower energy



Unpacking Procedure Unpacking Procedure (cont)(cont)

• Do something with hotcells

• When all selected towers have been processed, fill a vector

(CalUnpEt) of pointers to layer 0 of CalUnpData array

for all new towers that have energy deposited in them.

• Sort CalUnpEt according to Et of associated tower in a

decreasing order.

– Assumes vertex = (0,0,0) - may apply correction for other

vertices

– expensive - requires atan(e - ): uses a lookup table instead of

calculating it each time



Unpacking Procedure: Unpacking Procedure: Reset()Reset()

• Loop over all unpacked towers and cells, and zero CalUnpData

• Reset vector of all unpacked modules

• Reset vector of all unpacked towers

• Accumulate statistics for hot cell killer



Timing StudiesTiming Studies

• Majority of time spent in low level routines, such as extracting the module ID for a given seed tower, or translating physics cell addresses to electronic addresses. Already uses lookup tables for some of this, may use more.

• Significant time spent sorting and unique-ing vectors.

• Time does not rise linearly with number of cells/towers unpacked.

• Impossible to say if current implementation is satisfactory, as we don’t have an optimized version of the D0RunII software that runs on NT

• WAY OUT OF DATE



Timing ResultsTiming Results

t-tbar sample, no lookup tables

running on d02ka




Using lookup tables




Unpacking Entire Detector




Directed unpacking, trigger threshold = 0.5GeV




Directed unpacking, trigger tower energy > 2 GeV




Directed unpacking, trigger tower energy > 2 GeV, radius = 7 towers




Directed unpacking, trigger tower energy > 5 GeV




Directed unpacking, trigger tower energy > 5.0 GeV, neighborhood = 7

intelligent (or not completely stupid) unpacking

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