Size of PicoDst structures

pico_size.C

#include <TFile.h>
#include <TTree.h>
#include <TBranch.h>
#include <TList.h>
#include <TObjArray.h>

void compareBranches(const char* filename = "pythia_for_full_sim.picoDst.root") {
    TFile* file = TFile::Open(filename, "READ");
    if (!file || file->IsZombie()) {
        printf("Error opening file\n");
        return;
    }
    TTree* tree = (TTree*)file->Get("PicoDst");
    Long64_t nEvents = tree->GetEntries();
    Long64_t totalBytes = tree->GetZipBytes();  // Uncompressed size of all branches

    printf("Total uncompressed size: %lld bytes, %.2f bytes/event\n",
           totalBytes, (double)totalBytes / nEvents);

    // List of branches to subset (example: "Event", "Track")
    const char* branchNames[] = {"FwdTracks", "FcsHits", "FcsClusters"};
    int nBranches = sizeof(branchNames) / sizeof(branchNames[0]);
    Long64_t subsetBytes = 0;

    for (int i = 0; i < nBranches; i++) {
        TBranch* branch = tree->GetBranch(branchNames[i]);
        if (branch) {
            Long64_t branchBytes = branch->GetZipBytes();
            subsetBytes += branchBytes;
            printf("Branch %s: %lld bytes, %.2f bytes/event\n",
                   branchNames[i], branchBytes, (double)branchBytes / nEvents);
        } else {
            printf("Branch %s not found\n", branchNames[i]);
        }
    }
    printf("Subset size: %lld bytes, %.2f bytes/event\n",
           subsetBytes, (double)subsetBytes / nEvents);
    printf("Subset fraction of total: %.2f%%\n",
           (double)subsetBytes / totalBytes * 100);

    file->Close();
}



void compareAllBranches(const char* filename = "pythia_for_full_sim.picoDst.root") {
    TFile* file = TFile::Open(filename, "READ");
    if (!file || file->IsZombie()) {
        printf("Error opening file\n");
        return;
    }
    TTree* tree = (TTree*)file->Get("PicoDst");
    if (!tree) {
        printf("Tree 'PicoDst' not found\n");
        file->Close();
        return;
    }

    Long64_t nEvents = tree->GetEntries();
    Long64_t totalBytes = tree->GetZipBytes();  // Uncompressed size of all branches
    printf("Total uncompressed size: %lld bytes, %.2f bytes/event\n",
           totalBytes, (double)totalBytes / nEvents);

    // Get all branches dynamically
    TObjArray* branches = tree->GetListOfBranches();
    int nBranches = branches->GetEntries();
    Long64_t sumBytes = 0;

    for (int i = 0; i < nBranches; i++) {
        TBranch* branch = (TBranch*)branches->At(i);
        const char* branchName = branch->GetName();
        Long64_t branchBytes = branch->GetZipBytes();
        sumBytes += branchBytes;
        printf("Branch %s: %lld bytes, %.2f bytes/event, %.2f%% of total\n",
               branchName, branchBytes, (double)branchBytes / nEvents,
               (double)branchBytes / totalBytes * 100);
    }

    printf("Sum of branch sizes: %lld bytes, %.2f bytes/event\n",
           sumBytes, (double)sumBytes / nEvents);
    printf("Sum as fraction of total: %.2f%%\n",
           (double)sumBytes / totalBytes * 100);

    file->Close();
}

void pico_size() {
    compareBranches();
}

PicoSizes.C

#include <iostream>
#include "StPicoEvent/StPicoEvent.h"
#include "StPicoEvent/StPicoTrack.h"
#include "StPicoEvent/StPicoBTowHit.h"
#include "StPicoEvent/StPicoBTofHit.h"
#include "StPicoEvent/StPicoMtdHit.h"
#include "StPicoEvent/StPicoEmcTrigger.h"
#include "StPicoEvent/StPicoBTofPidTraits.h"
#include "StPicoEvent/StPicoMtdPidTraits.h"
#include "StPicoEvent/StPicoEmcPidTraits.h"
#include "StPicoEvent/StPicoTrackCovMatrix.h"
#include "StPicoEvent/StPicoBEmcSmdEHit.h"
#include "StPicoEvent/StPicoBEmcSmdPHit.h"
#include "StPicoEvent/StPicoETofHit.h"
#include "StPicoEvent/StPicoETofPidTraits.h"
#include "StPicoEvent/StPicoFwdTrack.h"  // Forward tracks
#include "StPicoEvent/StPicoFcsHit.h"
#include "StPicoEvent/StPicoFcsCluster.h"

void printPicoDstSizes() {
    std::cout << "Size of PicoDst Classes (bytes):\n";
    std::cout << "------------------------------\n";
    std::cout << "StPicoEvent:         " << sizeof(StPicoEvent) << "\n";
    std::cout << "StPicoTrack:         " << sizeof(StPicoTrack) << "\n";
    std::cout << "StPicoBTowHit:       " << sizeof(StPicoBTowHit) << "\n";
    std::cout << "StPicoBTofHit:       " << sizeof(StPicoBTofHit) << "\n";
    std::cout << "StPicoMtdHit:        " << sizeof(StPicoMtdHit) << "\n";
    std::cout << "StPicoEmcTrigger:    " << sizeof(StPicoEmcTrigger) << "\n";
    std::cout << "StPicoBTofPidTraits: " << sizeof(StPicoBTofPidTraits) << "\n";
    std::cout << "StPicoMtdPidTraits:  " << sizeof(StPicoMtdPidTraits) << "\n";
    std::cout << "StPicoEmcPidTraits:  " << sizeof(StPicoEmcPidTraits) << "\n";
    std::cout << "StPicoTrackCovMatrix:" << sizeof(StPicoTrackCovMatrix) << "\n";
    std::cout << "StPicoBEmcSmdEHit:   " << sizeof(StPicoBEmcSmdEHit) << "\n";
    std::cout << "StPicoBEmcSmdPHit:   " << sizeof(StPicoBEmcSmdPHit) << "\n";
    std::cout << "StPicoETofHit:       " << sizeof(StPicoETofHit) << "\n";
    std::cout << "StPicoETofPidTraits: " << sizeof(StPicoETofPidTraits) << "\n";
    std::cout << "StPicoFwdTrack:      " << sizeof(StPicoFwdTrack) << "\n";
    std::cout << "StPicoFcsHit:        " << sizeof(StPicoFcsHit) << "\n";
    std::cout << "StPicoFcsCluster:    " << sizeof(StPicoFcsCluster) << "\n";
}

int main() {
    printPicoDstSizes();
    return 0;
}