[RF] Remove warnings about large pdf values and just check for infinity

Usually, when this warning happens, it's a false positive that annoys
users and they complain about it. Since the threshold is hardcoded, it
happens usually when your observable domains are narrow and the
probability density is high, i.e. when the order of magnitude of your
observable is small.

For example, when you have a uniform in the range 0.0 to 1.1e-6, you'll
get this warning for every pdf evaluation for no reason.

Or if you have a RooProdPdf, this can happen even more easily: the
product of two uniforms over the domain 0.0 to 1.1e-3 each will also
reach the 1e-6 threshold.

So it's better to only check for infinite values, which was probably the
intention anyway.

roofit/batchcompute/res/RooBatchCompute.h

@@ -109,7 +109,7 @@ enum Computer {
 struct ReduceNLLOutput {
    double nllSum = 0.0;
    double nllSumCarry = 0.0;
-   std::size_t nLargeValues = 0;
+   std::size_t nInfiniteValues = 0;
    std::size_t nNonPositiveValues = 0;
    std::size_t nNaNValues = 0;
 };

roofit/batchcompute/src/RooBatchCompute.cxx

@@ -242,15 +242,15 @@ namespace {
 
 inline std::pair<double, double> getLog(double prob, ReduceNLLOutput &out)
 {
-   if (std::abs(prob) > 1e6) {
-      out.nLargeValues++;
-   }
-
    if (prob <= 0.0) {
       out.nNonPositiveValues++;
       return {std::log(prob), -prob};
    }
 
+   if (std::isinf(prob)) {
+      out.nInfiniteValues++;
+   }
+
    if (std::isnan(prob)) {
       out.nNaNValues++;
       return {prob, RooNaNPacker::unpackNaN(prob)};

roofit/roofitcore/src/RooAbsPdf.cxx

@@ -185,16 +185,16 @@ namespace {
 inline double getLog(double prob, RooAbsReal const *caller)
 {
 
-   if (std::abs(prob) > 1e6) {
-      oocoutW(caller, Eval) << "RooAbsPdf::getLogVal(" << caller->GetName()
-                            << ") WARNING: top-level pdf has a large value: " << prob << std::endl;
-   }
-
    if (prob < 0) {
       caller->logEvalError("getLogVal() top-level p.d.f evaluates to a negative number");
       return RooNaNPacker::packFloatIntoNaN(-prob);
    }
 
+   if (std::isinf(prob)) {
+      oocoutW(caller, Eval) << "RooAbsPdf::getLogVal(" << caller->GetName()
+                            << ") WARNING: top-level pdf has an infinite value" << std::endl;
+   }
+
    if (prob == 0) {
       caller->logEvalError("getLogVal() top-level p.d.f evaluates to zero");
 

roofit/roofitcore/src/RooNLLVarNew.cxx

@@ -259,9 +259,9 @@ void RooNLLVarNew::doEval(RooFit::EvalContext &ctx) const
    auto nllOut = RooBatchCompute::reduceNLL(config, probas, _weightSquared ? weightsSumW2 : weights,
                                             _doBinOffset ? ctx.at(*_offsetPdf) : std::span<const double>{});
 
-   if (nllOut.nLargeValues > 0) {
+   if (nllOut.nInfiniteValues > 0) {
       oocoutW(&*_pdf, Eval) << "RooAbsPdf::getLogVal(" << _pdf->GetName()
-                            << ") WARNING: top-level pdf has unexpectedly large values" << std::endl;
+                            << ") WARNING: top-level pdf has some infinite values" << std::endl;
    }
    for (std::size_t i = 0; i < nllOut.nNonPositiveValues; ++i) {
       _pdf->logEvalError("getLogVal() top-level p.d.f not greater than zero");