[hist] raise error when inf/nan edges in TAxis of fixed binwidth

Author: ferdymercury

hist/hist/src/TAxis.cxx

@@ -27,6 +27,7 @@
 #include "snprintf.h"
 
 #include <iostream>
+#include <cmath>
 #include <ctime>
 #include <cassert>
 
@@ -779,10 +780,20 @@ void TAxis::SaveAttributes(std::ostream &out, const char *name, const char *subn
 
 ////////////////////////////////////////////////////////////////////////////////
 /// Initialize axis with fix bins
+///
+/// An error is printed if xup or xlow are infinite/nan
+/// (due to resulting undefined fixed bin width)
+///
+/// Set xup <= xlow to force the axis range and number of bins to be automatically
+/// deduced after buffer is full or BufferEmpty is called
 
 void TAxis::Set(Int_t nbins, Double_t xlow, Double_t xup)
 {
    fNbins   = nbins;
+   if (std::isinf(xlow) || std::isinf(xup))
+      Error("TAxis::Set", "fixed binwidth not compatible with infinite lower/upper edges");
+   if (std::isnan(xlow) || std::isnan(xup))
+      Error("TAxis::Set", "lower/upper edges should not be NaN");
    fXmin    = xlow;
    fXmax    = xup;
    if (!fParent) SetDefaults();
@@ -791,6 +802,8 @@ void TAxis::Set(Int_t nbins, Double_t xlow, Double_t xup)
 
 ////////////////////////////////////////////////////////////////////////////////
 /// Initialize axis with variable bins
+///
+/// An error is printed if bin edges are not in strictly increasing order
 
 void TAxis::Set(Int_t nbins, const Float_t *xbins)
 {
@@ -801,7 +814,7 @@ void TAxis::Set(Int_t nbins, const Float_t *xbins)
       fXbins.fArray[bin] = xbins[bin];
    for (bin=1; bin<= fNbins; bin++)
       if (fXbins.fArray[bin] <= fXbins.fArray[bin - 1])
-         Error("TAxis::Set", "bins must be in increasing order");
+         Error("TAxis::Set", "bin edges must be in increasing order");
    fXmin      = fXbins.fArray[0];
    fXmax      = fXbins.fArray[fNbins];
    if (!fParent) SetDefaults();
@@ -819,7 +832,7 @@ void TAxis::Set(Int_t nbins, const Double_t *xbins)
       fXbins.fArray[bin] = xbins[bin];
    for (bin=1; bin<= fNbins; bin++)
       if (fXbins.fArray[bin] <= fXbins.fArray[bin - 1])
-         Error("TAxis::Set", "bins must be in increasing order");
+         Error("TAxis::Set", "bin edges must be in increasing order");
    fXmin      = fXbins.fArray[0];
    fXmax      = fXbins.fArray[fNbins];
    if (!fParent) SetDefaults();

hist/hist/src/TH2Poly.cxx

@@ -146,7 +146,7 @@ times, it is better to divide into a small number of cells.
 
 TH2Poly::TH2Poly()
 {
-   Initialize(0., 0., 0., 0., 25, 25);
+   Initialize(0., 0., 0., 0., 25, 25); // automatic axis range calculation
    SetName("NoName");
    SetTitle("NoTitle");
    SetFloat();

hist/hist/test/test_TH1.cxx

@@ -318,5 +318,9 @@ TEST(TH1, SetBufferedSumw2)
 // https://github.com/root-project/root/issues/20185
 TEST(TAxis, EqualBinEdges)
 {
-   ROOT_EXPECT_ERROR(TAxis _({1, 1}), "TAxis::Set", "bins must be in increasing order");
+   ROOT_EXPECT_ERROR(TAxis _({1, 1}), "TAxis::Set", "bin edges must be in increasing order");
+   ROOT_EXPECT_ERROR(TAxis _(1, -std::numeric_limits<double>::infinity(), 0), "TAxis::Set", "fixed binwidth not compatible with infinite lower/upper edges");
+   ROOT_EXPECT_ERROR(TAxis _(1, 0., std::numeric_limits<double>::infinity()), "TAxis::Set", "fixed binwidth not compatible with infinite lower/upper edges");
+   ROOT_EXPECT_ERROR(TAxis _(1, std::numeric_limits<double>::quiet_NaN(), 0), "TAxis::Set", "lower/upper edges should not be NaN");
+   ROOT_EXPECT_ERROR(TAxis _(1, 0, std::numeric_limits<double>::quiet_NaN()), "TAxis::Set", "lower/upper edges should not be NaN");
 }

test/stressHistogram.cxx

@@ -6269,26 +6269,26 @@ bool testMerge1DWithBuffer(bool allNoLimits)
    // where different axis are used, BUT the largest bin width must be
    // a multiple of the smallest bin width
 
-   double x1 = 1; double x2 = 0;
+   double x1 = 1; double x2 = 0; // i.e. automatic axis range calculation
    if (!allNoLimits) {
       // case when one of the histogram has limits (mix mode)
       x1 = minRange; x2 = maxRange;
    }
 
    TH1D* h0 = new TH1D("h0", "h0-Title", numberOfBins, 1, 0);
    TH1D* h1 = new TH1D("h1", "h1-Title", numberOfBins, x1, x2);
-   TH1D* h2 = new TH1D("h2", "h2-Title", 1,1,0);
-   TH1D* h3 = new TH1D("h3", "h3-Title", 1,1,0);
-   TH1D* h4 = new TH1D("h4", "h4-Title", numberOfBins, x1,x2);
+   TH1D* h2 = new TH1D("h2", "h2-Title", 1, 1, 0);
+   TH1D* h3 = new TH1D("h3", "h3-Title", 1, 1, 0);
+   TH1D* h4 = new TH1D("h4", "h4-Title", numberOfBins, x1, x2);
 
    h0->Sumw2(); h1->Sumw2();h2->Sumw2();h4->Sumw2();
    // The below histograms will be merged into h0, so they all need to fit into the buffer.
    // Otherwise, the axis ranges will be computed already during the partial merge.
    h0->SetBuffer(nEvents * 10);
-   h1->SetBuffer(nEvents*10);
-   h2->SetBuffer(nEvents*10);
-   h3->SetBuffer(nEvents*10);
-   h4->SetBuffer(nEvents*10);
+   h1->SetBuffer(nEvents * 10);
+   h2->SetBuffer(nEvents * 10);
+   h3->SetBuffer(nEvents * 10);
+   h4->SetBuffer(nEvents * 10);
 
 
    for ( Int_t e = 0; e < nEvents; ++e ) {