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[tree] return NaN instead of zero when out of bonds in TreeFormula #18766

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Merged
merged 3 commits into from
May 17, 2025
Merged

[tree] return NaN instead of zero when out of bonds in TreeFormula #18766

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d5b6a8c
[tree] return NaN instead of zero when out of bonds in TreeFormula
ferdymercury May 5, 2025
46f02fa
[test] Improve test explicit check for NaN
ferdymercury May 5, 2025
7966c82
[doc] Improve TTreeFormula doc and fix example
ferdymercury May 5, 2025
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15 changes: 12 additions & 3 deletions roottest/root/treeformula/array/execOutOfBounds.C
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Original file line number Diff line number Diff line change
Expand Up @@ -4,11 +4,20 @@ int execOutOfBounds() {
{
#endif
TFile *_file0 = TFile::Open("run133.root");
TTree *t; _file0->GetObject("t",t);
auto t = _file0->Get<TTree>("t");
// ThetaDeg is a dynamic array with indices going from 0 to (ringtouche_DE1 - 1)
TTreeFormula tf("tf", "ThetaDeg", t);
t->GetEntry(0); // ringtouche for entry 0 is 0
auto res = tf.EvalInstance(1); // ThetaDeg[1] goes out of bonds
if (!TMath::IsNaN(res)) {
printf("Error: evaluated instance is %f rather than NaN\n", res);
return 1;
}
TH2F *h2 = new TH2F("h2","h2",5,0,5,100,0,100);
t->Draw("ThetaDeg[ringtouche_DE1]:ringtouche_DE1>>h2","","colz goff");
if ( (int)(h2->GetMean(1)*1000) != 3) {
printf("Error: x mean is %f rather than 0.003\n",h2->GetMean(1));
// Filling NaNs increases entry number but does not change any bin content
if ( (int)(h2->GetMean(1)*1000) != 0) {
printf("Error: x mean is %f rather than 0.000\n",h2->GetMean(1));
return 1;
}
if ( (int)(h2->GetMean(2)*10) != 0) {
Expand Down
77 changes: 69 additions & 8 deletions tree/treeplayer/src/TTreeFormula.cxx
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Expand Up @@ -3759,7 +3759,7 @@ const char* TTreeFormula::EvalStringInstance(Int_t instance)
const Int_t real_instance = GetRealInstance(instance,0); \
\
if (instance==0) fNeedLoading = true; \
if (real_instance>=fNdata[0]) return 0; \
if (real_instance>=fNdata[0]) return TMath::SignalingNaN(); \
\
/* Since the only operation in this formula is reading this branch, \
we are guaranteed that this function is first called with instance==0 and \
Expand Down Expand Up @@ -3793,7 +3793,7 @@ const char* TTreeFormula::EvalStringInstance(Int_t instance)
#define TREE_EVAL_INIT \
const Int_t real_instance = GetRealInstance(instance,0); \
\
if (real_instance>=fNdata[0]) return 0; \
if (real_instance>=fNdata[0]) return TMath::SignalingNaN(); \
\
if (fAxis) { \
char * label; \
Expand Down Expand Up @@ -3845,13 +3845,13 @@ const char* TTreeFormula::EvalStringInstance(Int_t instance)
} \
} \
} \
if (real_instance>=fNdata[code]) return 0;
if (real_instance>=fNdata[code]) return TMath::SignalingNaN();

#define TREE_EVAL_INIT_LOOP \
/* Now let calculate what physical instance we really need. */ \
const Int_t real_instance = GetRealInstance(instance,code); \
\
if (real_instance>=fNdata[code]) return 0;
if (real_instance>=fNdata[code]) return TMath::SignalingNaN();


template<typename T> T Summing(TTreeFormula *sum) {
Expand Down Expand Up @@ -3993,14 +3993,75 @@ template<> inline Long64_t TTreeFormula::GetConstant(Int_t k) { return (Long64_t
/// \tparam T The type used to interpret the numbers then used for the operations
/// \param instance iteration instance
/// \param stringStackArg formula as string
/// \return the result of the evaluation
/// \return the result of the evaluation, or a signaling NaN if out of bounds
///
/// \warning Care has to be taken before calling this function with std::vector
/// or dynamically sized objects, rather than plain fixed-size arrays.
/// For example, this works without problems:
/// ~~~{.cpp}
/// TTree t("t", "t");
/// Float_t x[2]{};
/// t.Branch("xa", &x, "x[2]/F");
/// x[1] = 1;
/// t.Fill();
/// x[1] = 2;
/// t.Fill();
/// t.Scan();
/// TTreeFormula tfx("tfx", "xa[1]", &t);
/// t.GetEntry(0);
/// tfx.EvalInstance()
/// t.GetEntry(1);
/// tfx.EvalInstance()
/// ~~~
/// But the following fails (independently on whether the size changed or not between entries):
/// ~~~{.cpp}
/// TTree t("t", "t");
/// vector<Short_t> v;
/// t.Branch("vec", &v);
/// v.push_back(2);
/// v.push_back(3);
/// t.Fill();
/// v.clear();
/// v.push_back(4);
/// v.push_back(5);
/// t.Fill();
/// t.Scan();
/// TTreeFormula tfv1("tfv1", "vec[1]", &t);
/// TTreeFormula tfv("tfv", "vec", &t);
/// t.GetEntry(0);
/// tfv1.EvalInstance()
/// tfv.EvalInstance(1)
/// t.GetEntry(1);
/// tfv1.EvalInstance()
/// tfv.EvalInstance(1)
/// ~~~
/// To prevent this, when working with objects with dynamic size for each entry, one needs
/// to mimick what TTree::Scan does, i.e. to check the value of
/// `GetNdata()` before calling `EvalInstance()`:
/// ~~~{.cpp}
/// t.GetEntry(0);
/// if (tfv1.GetNdata() > 0)
/// tfv1.EvalInstance()
/// if (tfv.GetNdata() > 1)
/// tfv.EvalInstance(1)
/// t.GetEntry(1);
/// if (tfv1.GetNdata() > 0)
/// tfv1.EvalInstance()
/// if (tfv.GetNdata() > 1)
/// tfv.EvalInstance(1)
/// ~~~
/// Note that for `tfv1`, even if the index is fixed in the formula and even if each entry
/// had the same std::vector size, since the formula contains a branch with theoretically variable size,
/// one must check GetNData() as there might 0 or 1 answers. Since even with fixed index,
/// the collection might be too small to fulfill it.
/// TTreeFormula::GetMultiplicity tells you (indirectly) whether you need to call GetNData or not for a given formula.

template<typename T>
T TTreeFormula::EvalInstance(Int_t instance, const char *stringStackArg[])
{
// Note that the redundancy and structure in this code is tailored to improve
// efficiencies.
if (TestBit(kMissingLeaf)) return 0;
if (TestBit(kMissingLeaf)) return TMath::SignalingNaN();
if (fNoper == 1 && fNcodes > 0) {

switch (fLookupType[0]) {
Expand Down Expand Up @@ -4059,7 +4120,7 @@ T TTreeFormula::EvalInstance(Int_t instance, const char *stringStackArg[])
}
return fx->EvalInstance<T>(instance);
}
default: return 0;
default: return TMath::SignalingNaN();
}
}

Expand Down Expand Up @@ -4443,7 +4504,7 @@ T TTreeFormula::EvalInstance(Int_t instance, const char *stringStackArg[])
Long64_t treeEntry = br->GetTree()->GetReadEntry();
R__LoadBranch(br,treeEntry,true);
}
if (real_instance>=fNdata[string_code]) return 0;
if (real_instance>=fNdata[string_code]) return TMath::SignalingNaN();
}
pos2++;
if (fLookupType[string_code]==kDirect) {
Expand Down
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