GooFit · henryiii · May 18, 2022 · Feb 3, 2021 · Mar 9, 2021 · Mar 9, 2021
diff --git a/include/goofit/fitting/FitManagerMinuit2.h b/include/goofit/fitting/FitManagerMinuit2.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Minuit2/FunctionMinimum.h>
+#include <Minuit2/MnScan.h>
 
 #include <memory>
 
@@ -29,6 +30,8 @@ class FitManagerMinuit2 {
     /// Get a pointer to the fcn
     auto getFCN() -> FCN * { return &fcn_; }
 
+    ROOT::Minuit2::MnScan getMnScan();
+
     /// Check to see if fit is valid
     operator bool() const { return retval_ == FitErrors::Valid; }
 
@@ -41,11 +44,19 @@ class FitManagerMinuit2 {
     /// Get the fitting verbosity
     auto getVerbosity() const -> int { return verbosity; }
 
+    // Get the minos errors
+    std::vector<std::pair<double, double>> getMinosErrors() const { return minos_errors; }
+
+    // Run Minos error calculation
+    void setMinos(bool minos_flag = 1) { minos = minos_flag; }
+
   private:
     Params upar_;
     FCN fcn_;
     unsigned int maxfcn_{0};
     FitErrors retval_{FitErrors::NotRun};
     int verbosity{3};
+    std::vector<std::pair<double, double>> minos_errors;
+    bool minos{0};
 };
 } // namespace GooFit
diff --git a/include/goofit/fitting/Params.h b/include/goofit/fitting/Params.h
@@ -31,6 +31,9 @@ class Params : public Minuit2::MnUserParameters {
 
     Params(PdfBase &pdf);
 
+    // Get vector of GooFit Variables.
+    std::vector<Variable> GetGooFitParams() const { return vars_; }
+
     /// Read the values back into GooFit
     void SetGooFitParams(const Minuit2::MnUserParameterState &input);
 

diff --git a/python/Minuit2/CMakeLists.txt b/python/Minuit2/CMakeLists.txt
@@ -9,7 +9,9 @@ add_library(
   MnPrint.cpp
   MnUserCovariance.cpp
   MnUserParameterState.cpp
-  MnUserParameters.cpp)
+  MnUserParameters.cpp
+  MnScan.cpp
+  MnMinos.cpp)
 
 process_pybind_module(minuit2)
 target_link_libraries(minuit2 PUBLIC ROOT::Minuit2)

diff --git a/python/Minuit2/MnMinos.cpp b/python/Minuit2/MnMinos.cpp
@@ -0,0 +1,45 @@
+#include <pybind11/pybind11.h>
+
+#include <pybind11/stl.h>
+
+#include <Minuit2/FCNBase.h>
+#include <Minuit2/MnMinos.h>
+#include <Minuit2/MinosError.h>
+#include <Minuit2/FunctionMinimum.h>
+#include <Minuit2/MnUserParameters.h>
+
+namespace py = pybind11;
+using namespace pybind11::literals;
+
+using namespace ROOT::Minuit2;
+
+void init_MnMinos(py::module &m) {
+    py::class_<MinosError>(m, "MinosError")
+
+        .def_property_readonly("number", &MinosError::Parameter)
+        .def_property_readonly("lower", &MinosError::Lower)
+        .def_property_readonly("upper", &MinosError::Upper)
+        .def_property_readonly("is_valid", &MinosError::IsValid)
+        .def_property_readonly("lower_valid", &MinosError::LowerValid)
+        .def_property_readonly("upper_valid", &MinosError::UpperValid)
+        .def_property_readonly("at_lower_limit", &MinosError::AtLowerLimit)
+        .def_property_readonly("at_upper_limit", &MinosError::AtUpperLimit)
+        .def_property_readonly("at_lower_max_fcn", &MinosError::AtLowerMaxFcn)
+        .def_property_readonly("at_upper_max_fcn", &MinosError::AtUpperMaxFcn)
+        .def_property_readonly("lower_new_min", &MinosError::LowerNewMin)
+        .def_property_readonly("upper_new_min", &MinosError::UpperNewMin)
+        .def_property_readonly("nfcn", &MinosError::NFcn)
+        .def_property_readonly("min", &MinosError::Min)
+
+        ;
+
+    py::class_<MnMinos>(m, "MnMinos")
+        .def(py::init<const FCNBase &, const FunctionMinimum &, unsigned int>(), "fcn"_a, "min"_a, "stra"_a = 1)
+        .def("__call__",
+             &MnMinos::operator(),
+             "Minimize the function, returns a function minimum",
+             "par"_a,
+             "maxfcn"_a    = 0,
+             "tolerance"_a = 0.1);
+    ;
+}
diff --git a/python/Minuit2/MnScan.cpp b/python/Minuit2/MnScan.cpp
@@ -0,0 +1,17 @@
+#include <pybind11/pybind11.h>
+#include <pybind11/stl.h>
+
+#include <sstream>
+
+#include <Minuit2/MnScan.h>
+#include <Minuit2/MnPrint.h>
+
+namespace py = pybind11;
+using namespace pybind11::literals;
+
+using namespace ROOT::Minuit2;
+
+void init_MnScan(py::module &m) {
+    py::class_<MnScan>(m, "MnScan")
+        .def("Scan", &MnScan::Scan, "Scan parameter.", "par"_a, "maxsteps"_a = 41, "low"_a = 0, "high"_a = 0);
+}
diff --git a/python/goofit/FitManager.cpp b/python/goofit/FitManager.cpp
@@ -3,18 +3,27 @@
 #include <pybind11/iostream.h>
 #include <pybind11/stl.h>
 
+#include <Minuit2/MnUserParameters.h>
+#include <Minuit2/FCNBase.h>
+
 #include <goofit/PdfBase.h>
 #include <goofit/PyProps.h>
 #include <goofit/fitting/FitManagerMinuit2.h>
+#include <goofit/fitting/Params.h>
 
 #include <iostream>
 
 using namespace GooFit;
 
 void init_FitManager(py::module &m) {
-    py::class_<FCN>(m, "FCN");
+    py::class_<FCN, Minuit2::FCNBase>(m, "FCN").def(py::init<Params &>(), "params"_a);
+
+    py::class_<Params, Minuit2::MnUserParameters>(m, "Params")
+        .def(py::init<PdfBase &>(), "pdf"_a)
+        .def("SetGooFitParams", &Params::SetGooFitParams, "input"_a)
+        .def("size", &Params::size)
+        .def("make_minuit_vector", &Params::make_minuit_vector)
 
-    py::class_<Params>(m, "Params")
         // clang-format off
         ADD_PROP_WO(record, set_record, Params)
         ADD_PROP_RO(recorded, get_recorded, Params)
@@ -24,7 +33,10 @@ void init_FitManager(py::module &m) {
     py::class_<FitManagerMinuit2>(m, "FitManager")
         .def(py::init<PdfBase *>())
         .def("fit", &FitManagerMinuit2::fit, py::call_guard<py::scoped_ostream_redirect>())
+        .def("getMinosErrors", &FitManagerMinuit2::getMinosErrors)
+        .def("getMnScan", &FitManagerMinuit2::getMnScan)
         .def("__int__", &FitManagerMinuit2::operator int)
+        .def("setMinos", &FitManagerMinuit2::setMinos)
         .def("__bool__", &FitManagerMinuit2::operator bool)    // Py3
         .def("__nonzero__", &FitManagerMinuit2::operator bool) // Py2
 

diff --git a/src/goofit/FitManagerMinuit2.cpp b/src/goofit/FitManagerMinuit2.cpp
@@ -1,4 +1,5 @@
 #include <goofit/fitting/FitManagerMinuit2.h>
+#include <goofit/fitting/Params.h>
 
 #include <goofit/Color.h>
 #include <goofit/Version.h>
@@ -8,6 +9,8 @@
 #include <Minuit2/MnPrint.h>
 #include <Minuit2/MnUserParameterState.h>
 #include <Minuit2/MnUserParameters.h>
+#include <Minuit2/MnScan.h>
+#include <Minuit2/MnMinos.h>
 
 #include <CLI/Timer.hpp>
 
@@ -16,6 +19,8 @@
 #else
 #include <RVersion.h>
 #endif
+#include <iostream>
+#include <vector>
 
 namespace GooFit {
 
@@ -46,6 +51,30 @@ auto FitManagerMinuit2::fit() -> Minuit2::FunctionMinimum {
     CLI::Timer avetimer{"Average time per call"};
     Minuit2::FunctionMinimum min = migrad(maxfcn_);
 
+    if(minos) {
+        Minuit2::MnMinos minos{fcn_, min}; // Create MINOS errors
+        std::vector<Variable> variables = upar_.GetGooFitParams();
+        for(Variable &var : variables) {
+            if(var.IsFixed())
+                continue;
+            else {
+                minos_errors.push_back(minos(var.getFitterIndex()));
+            }
+        }
+        // output
+        int counter = 0;
+        std::cout << "1-sigma minos errors: " << std::endl;
+        for(Variable &var : variables) {
+            if(var.IsFixed())
+                continue;
+            else {
+                std::cout << var.getName() << ": " << minos_errors[counter].first << " " << minos_errors[counter].second
+                          << std::endl;
+                counter += 1;
+            }
+        }
+    }
+
     // Print nice output
     if(verbosity > 0) {
         std::cout << GooFit::reset << (min.IsValid() ? GooFit::green : GooFit::red);
@@ -85,4 +114,10 @@ auto FitManagerMinuit2::fit() -> Minuit2::FunctionMinimum {
     return min;
 }
 
+Minuit2::MnScan FitManagerMinuit2::getMnScan() {
+    Minuit2::MnScan mnscan{fcn_, upar_};
+
+    return mnscan;
+}
+
 } // namespace GooFit