#include "openmc/output.h"

#include <algorithm> // for transform, max

#include <cstdio> // for stdout

#include <cstring> // for strlen

#include <ctime> // for time, localtime

#include <fstream>

#include <iomanip> // for setw, setprecision, put_time

#include <ios> // for fixed, scientific, left

#include <iostream>

#include <sstream>

#include <unordered_map>

#include <utility> // for pair

#include <fmt/core.h>

#include <fmt/ostream.h>

#ifdef _OPENMP

#include <omp.h>

#endif

#include "openmc/tensor.h"

#include "openmc/capi.h"

#include "openmc/cell.h"

#include "openmc/constants.h"

#include "openmc/eigenvalue.h"

#include "openmc/error.h"

#include "openmc/geometry.h"

#include "openmc/lattice.h"

#include "openmc/math_functions.h"

#include "openmc/message_passing.h"

#include "openmc/mgxs_interface.h"

#include "openmc/nuclide.h"

#include "openmc/plot.h"

#include "openmc/random_ray/flat_source_domain.h"

#include "openmc/reaction.h"

#include "openmc/settings.h"

#include "openmc/simulation.h"

#include "openmc/surface.h"

#include "openmc/tallies/derivative.h"

#include "openmc/tallies/filter.h"

#include "openmc/tallies/tally.h"

#include "openmc/tallies/tally_scoring.h"

#include "openmc/timer.h"

namespace openmc {

#ifdef OPENMC_ENABLE_STRICT_FP

const bool STRICT_FP_ENABLED = true;

#else

const bool STRICT_FP_ENABLED = false;

#endif

//==============================================================================

void title()

{

fmt::print(" %%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%\n"

" %%%%%%%%%%%%%%%%%%%%%%%%\n"

" ############### %%%%%%%%%%%%%%%%%%%%%%%%\n"

" ################## %%%%%%%%%%%%%%%%%%%%%%%\n"

" ################### %%%%%%%%%%%%%%%%%%%%%%%\n"

" #################### %%%%%%%%%%%%%%%%%%%%%%\n"

" ##################### %%%%%%%%%%%%%%%%%%%%%\n"

" ###################### %%%%%%%%%%%%%%%%%%%%\n"

" ####################### %%%%%%%%%%%%%%%%%%\n"

" ####################### %%%%%%%%%%%%%%%%%\n"

" ###################### %%%%%%%%%%%%%%%%%\n"

" #################### %%%%%%%%%%%%%%%%%\n"

" ################# %%%%%%%%%%%%%%%%%\n"

" ############### %%%%%%%%%%%%%%%%\n"

" ############ %%%%%%%%%%%%%%%\n"

" ######## %%%%%%%%%%%%%%\n"

" %%%%%%%%%%%\n\n");

// Write version information

fmt::print(

" | The OpenMC Monte Carlo Code\n"

" Copyright | 2011-2026 MIT, UChicago Argonne LLC, and contributors\n"

" License | https://docs.openmc.org/en/latest/license.html\n"

" Version | {}.{}.{}{}{}\n",

VERSION_MAJOR, VERSION_MINOR, VERSION_RELEASE, VERSION_DEV ? "-dev" : "",

VERSION_COMMIT_COUNT);

fmt::print(" Commit Hash | {}\n", VERSION_COMMIT_HASH);

// Write the date and time

fmt::print(" Date/Time | {}\n", time_stamp());

#ifdef OPENMC_MPI

// Write number of processors

fmt::print(" MPI Processes | {}\n", mpi::n_procs);

#endif

#ifdef _OPENMP

// Write number of OpenMP threads

fmt::print(" OpenMP Threads | {}\n", omp_get_max_threads());

#endif

fmt::print("\n");

std::fflush(stdout);

}

//==============================================================================

std::string header(const char* msg)

{

// Determine how many times to repeat the '=' character.

int n_prefix = (63 - strlen(msg)) / 2;

int n_suffix = n_prefix;

if ((strlen(msg) % 2) == 0)

++n_suffix;

// Convert to uppercase.

std::string upper(msg);

std::transform(upper.begin(), upper.end(), upper.begin(), ::toupper);

// Add ===> <=== markers.

std::stringstream out;

out << ' ';

for (int i = 0; i < n_prefix; i++)

out << '=';

out << "> " << upper << " <";

for (int i = 0; i < n_suffix; i++)

out << '=';

return out.str();

}

std::string header(const std::string& msg)

{

return header(msg.c_str());

}

void header(const char* msg, int level)

{

auto out = header(msg);

// Print header based on verbosity level.

if (settings::verbosity >= level) {

fmt::print("\n{}\n\n", out);

std::fflush(stdout);

}

}

//==============================================================================

std::string time_stamp()

{

std::stringstream ts;

std::time_t t = std::time(nullptr); // get time now

ts << std::put_time(std::localtime(&t), "%Y-%m-%d %H:%M:%S");

return ts.str();

}

//==============================================================================

void print_particle(Particle& p)

{

// Display particle type and ID.

switch (p.type().pdg_number()) {

case PDG_NEUTRON:

fmt::print("Neutron ");

break;

case PDG_PHOTON:

fmt::print("Photon ");

break;

case PDG_ELECTRON:

fmt::print("Electron ");

break;

case PDG_POSITRON:

fmt::print("Positron ");

break;

default:

fmt::print("Particle {} ", p.type().str());

}

fmt::print("{}\n", p.id());

// Display particle geometry hierarchy.

for (auto i = 0; i < p.n_coord(); i++) {

fmt::print(" Level {}\n", i);

if (p.coord(i).cell() != C_NONE) {

const Cell& c {*model::cells[p.coord(i).cell()]};

fmt::print(" Cell = {}\n", c.id_);

}

if (p.coord(i).universe() != C_NONE) {

const Universe& u {*model::universes[p.coord(i).universe()]};

fmt::print(" Universe = {}\n", u.id_);

}

if (p.coord(i).lattice() != C_NONE) {

const Lattice& lat {*model::lattices[p.coord(i).lattice()]};

fmt::print(" Lattice = {}\n", lat.id_);

fmt::print(" Lattice position = ({},{},{})\n",

p.coord(i).lattice_index()[0], p.coord(i).lattice_index()[1],

p.coord(i).lattice_index()[2]);

}

fmt::print(" r = {}\n", p.coord(i).r());

fmt::print(" u = {}\n", p.coord(i).u());

}

// Display miscellaneous info.

if (p.surface() != SURFACE_NONE) {

// Surfaces identifiers are >= 1, but indices are >= 0 so we need -1

const Surface& surf {*model::surfaces[p.surface_index()]};

fmt::print(" Surface = {}\n", (p.surface() > 0) ? surf.id_ : -surf.id_);

}

fmt::print(" Weight = {}\n", p.wgt());

if (settings::run_CE) {

fmt::print(" Energy = {}\n", p.E());

} else {

fmt::print(" Energy Group = {}\n", p.g());

}

fmt::print(" Delayed Group = {}\n\n", p.delayed_group());

}

//==============================================================================

void print_plot()

{

header("PLOTTING SUMMARY", 5);

if (settings::verbosity < 5)

return;

for (const auto& pl : model::plots) {

fmt::print("Plot ID: {}\n", pl->id());

fmt::print("Plot file: {}\n", pl->path_plot());

fmt::print("Universe depth: {}\n", pl->level());

pl->print_info(); // prints type-specific plot info

fmt::print("\n");

}

}

//==============================================================================

void print_overlap_check()

{

#ifdef OPENMC_MPI

vector<int64_t> temp(model::overlap_check_count);

mpi::reduce(temp.data(), model::overlap_check_count.data(),

model::overlap_check_count.size(), MPI_SUM, 0, mpi::intracomm);

#endif

if (mpi::master) {

header("cell overlap check summary", 1);

fmt::print(" Cell ID No. Overlap Checks\n");

vector<int32_t> sparse_cell_ids;

for (int i = 0; i < model::cells.size(); i++) {

fmt::print(

" {:8} {:17}\n", model::cells[i]->id_, model::overlap_check_count[i]);

if (model::overlap_check_count[i] < 10) {

sparse_cell_ids.push_back(model::cells[i]->id_);

}

}

fmt::print("\n There were {} cells with less than 10 overlap checks\n",

sparse_cell_ids.size());

for (auto id : sparse_cell_ids) {

fmt::print(" {}", id);

}

fmt::print("\n");

}

}

//==============================================================================

void print_usage()

{

if (mpi::master) {

fmt::print(

"Usage: openmc [options] [path]\n\n"

"Options:\n"

" -c, --volume Run in stochastic volume calculation mode\n"

" -g, --geometry-debug Run with geometry debugging on\n"

" -n, --particles Number of particles per generation\n"

" -p, --plot Run in plotting mode\n"

" -r, --restart Restart a previous run from a state point\n"

" or a particle restart file\n"

" -s, --threads Number of OpenMP threads\n"

" -t, --track Write tracks for all particles (up to "

"max_tracks)\n"

" -e, --event Run using event-based parallelism\n"

" -q, --verbosity Output verbosity\n"

" -v, --version Show version information\n"

" -h, --help Show this message\n");

}

}

//==============================================================================

void print_version()

{

if (mpi::master) {

fmt::print("OpenMC version {}.{}.{}{}{}\n", VERSION_MAJOR, VERSION_MINOR,

VERSION_RELEASE, VERSION_DEV ? "-dev" : "", VERSION_COMMIT_COUNT);

fmt::print("Commit hash: {}\n", VERSION_COMMIT_HASH);

fmt::print("Copyright (c) 2011-2026 MIT, UChicago Argonne LLC, and "

"contributors\nMIT/X license at "

"<https://docs.openmc.org/en/latest/license.html>\n");

}

}

//==============================================================================

void print_build_info()

{

const std::string n("no");

const std::string y("yes");

std::string mpi(n);

std::string phdf5(n);

std::string dagmc(n);

std::string libmesh(n);

std::string png(n);

std::string profiling(n);

std::string coverage(n);

std::string uwuw(n);

std::string strict_fp(n);

#ifdef PHDF5

phdf5 = y;

#endif

#ifdef OPENMC_MPI

mpi = y;

#endif

#ifdef OPENMC_DAGMC_ENABLED

dagmc = y;

#endif

#ifdef OPENMC_LIBMESH_ENABLED

libmesh = y;

#endif

#ifdef USE_LIBPNG

png = y;

#endif

#ifdef PROFILINGBUILD

profiling = y;

#endif

#ifdef COVERAGEBUILD

coverage = y;

#endif

#ifdef OPENMC_UWUW_ENABLED

uwuw = y;

#endif

#ifdef OPENMC_ENABLE_STRICT_FP

strict_fp = y;

#endif

// Wraps macro variables in quotes

#define STRINGIFY(x) STRINGIFY2(x)

#define STRINGIFY2(x) #x

if (mpi::master) {

fmt::print("Build type: {}\n", STRINGIFY(BUILD_TYPE));

fmt::print("Compiler ID: {} {}\n", STRINGIFY(COMPILER_ID),

STRINGIFY(COMPILER_VERSION));

fmt::print("MPI enabled: {}\n", mpi);

fmt::print("Parallel HDF5 enabled: {}\n", phdf5);

fmt::print("PNG support: {}\n", png);

fmt::print("DAGMC support: {}\n", dagmc);

fmt::print("libMesh support: {}\n", libmesh);

fmt::print("Coverage testing: {}\n", coverage);

fmt::print("Profiling flags: {}\n", profiling);

fmt::print("UWUW support: {}\n", uwuw);

fmt::print("Strict FP: {}\n", strict_fp);

}

}

//==============================================================================

void print_columns()

{

if (settings::entropy_on) {

fmt::print(" Bat./Gen. k Entropy Average k \n"

" ========= ======== ======== ====================\n");

} else {

fmt::print(" Bat./Gen. k Average k\n"

" ========= ======== ====================\n");

}

}

//==============================================================================

void print_generation()

{

// Determine overall generation index and number of active generations

int idx = overall_generation() - 1;

int n = simulation::current_batch > settings::n_inactive

? settings::gen_per_batch * simulation::n_realizations +

simulation::current_gen

: 0;

// write out batch/generation and generation k-effective

auto batch_and_gen = std::to_string(simulation::current_batch) + "/" +

std::to_string(simulation::current_gen);

fmt::print(" {:>9} {:8.5f}", batch_and_gen, simulation::k_generation[idx]);

// write out entropy info

if (settings::entropy_on) {

fmt::print(" {:8.5f}", simulation::entropy[idx]);

}

if (n > 1) {

fmt::print(" {:8.5f} +/-{:8.5f}", simulation::keff, simulation::keff_std);

}

fmt::print("\n");

std::fflush(stdout);

}

//==============================================================================

void show_time(const char* label, double secs, int indent_level)

{

int width = 33 - indent_level * 2;

fmt::print("{0:{1}} {2:<{3}} = {4:>10.4e} seconds\n", "", 2 * indent_level,

label, width, secs);

}

void show_rate(const char* label, double particles_per_sec)

{

fmt::print(" {:<33} = {:.6} particles/second\n", label, particles_per_sec);

}

void print_runtime()

{

using namespace simulation;

// display header block

header("Timing Statistics", 6);

if (settings::verbosity < 6)

return;

// display time elapsed for various sections

show_time("Total time for initialization", time_initialize.elapsed());

show_time("Reading cross sections", time_read_xs.elapsed(), 1);

show_time("Total time in simulation",

time_inactive.elapsed() + time_active.elapsed());

show_time("Time in transport only", time_transport.elapsed(), 1);

if (settings::event_based) {

show_time("Particle initialization", time_event_init.elapsed(), 2);

show_time("XS lookups", time_event_calculate_xs.elapsed(), 2);

show_time("Advancing", time_event_advance_particle.elapsed(), 2);

show_time("Surface crossings", time_event_surface_crossing.elapsed(), 2);

show_time("Collisions", time_event_collision.elapsed(), 2);

show_time("Particle death", time_event_death.elapsed(), 2);

}

if (settings::run_mode == RunMode::EIGENVALUE) {

show_time("Time in inactive batches", time_inactive.elapsed(), 1);

}

show_time("Time in active batches", time_active.elapsed(), 1);

if (settings::run_mode == RunMode::EIGENVALUE) {

show_time("Time synchronizing fission bank", time_bank.elapsed(), 1);

show_time("Sampling source sites", time_bank_sample.elapsed(), 2);

show_time("SEND/RECV source sites", time_bank_sendrecv.elapsed(), 2);

}

show_time("Time accumulating tallies", time_tallies.elapsed(), 1);

show_time("Time writing statepoints", time_statepoint.elapsed(), 1);

show_time("Total time for finalization", time_finalize.elapsed());

show_time("Total time elapsed", time_total.elapsed());

// Calculate particle rate in active/inactive batches

int n_active = simulation::current_batch - settings::n_inactive;

double speed_inactive = 0.0;

double speed_active;

if (settings::restart_run) {

if (simulation::restart_batch < settings::n_inactive) {

speed_inactive = (settings::n_particles *

(settings::n_inactive - simulation::restart_batch) *

settings::gen_per_batch) /

time_inactive.elapsed();

speed_active =

(settings::n_particles * n_active * settings::gen_per_batch) /

time_active.elapsed();

} else {

speed_active = (settings::n_particles *

(settings::n_batches - simulation::restart_batch) *

settings::gen_per_batch) /

time_active.elapsed();

}

} else {

if (settings::n_inactive > 0) {

speed_inactive = (settings::n_particles * settings::n_inactive *

settings::gen_per_batch) /

time_inactive.elapsed();

}

speed_active =

(settings::n_particles * n_active * settings::gen_per_batch) /

time_active.elapsed();

}

// display calculation rate

if (!(settings::restart_run &&

(simulation::restart_batch >= settings::n_inactive)) &&

settings::n_inactive > 0) {

show_rate("Calculation Rate (inactive)", speed_inactive);

}

show_rate("Calculation Rate (active)", speed_active);

// Display track rate when weight windows are enabled

if (settings::weight_windows_on) {

double speed_tracks =

simulation::simulation_tracks_completed / time_active.elapsed();

fmt::print(

" {:<33} = {:.6} tracks/second\n", "Track Rate (active)", speed_tracks);

}

}

//==============================================================================

std::pair<double, double> mean_stdev(const double* x, int n)

{

double mean = x[static_cast<int>(TallyResult::SUM)] / n;

double stdev =

n > 1 ? std::sqrt(std::max(0.0,

(x[static_cast<int>(TallyResult::SUM_SQ)] / n - mean * mean) /

(n - 1)))

: 0.0;

return {mean, stdev};

}

//==============================================================================

void print_results()

{

// display header block for results

header("Results", 4);

if (settings::verbosity < 4)

return;

// Calculate t-value for confidence intervals

int n = simulation::n_realizations;

double alpha, t_n1, t_n3;

if (settings::confidence_intervals) {

alpha = 1.0 - CONFIDENCE_LEVEL;

t_n1 = t_percentile(1.0 - alpha / 2.0, n - 1);

t_n3 = t_percentile(1.0 - alpha / 2.0, n - 3);

} else {

t_n1 = 1.0;

t_n3 = 1.0;

}

// write global tallies

const auto& gt = simulation::global_tallies;

double mean, stdev;

if (n > 1) {

if (settings::run_mode == RunMode::EIGENVALUE) {

std::tie(mean, stdev) = mean_stdev(&gt(GlobalTally::K_COLLISION, 0), n);

fmt::print(" k-effective (Collision) = {:.5f} +/- {:.5f}\n", mean,

t_n1 * stdev);

std::tie(mean, stdev) = mean_stdev(&gt(GlobalTally::K_TRACKLENGTH, 0), n);

fmt::print(" k-effective (Track-length) = {:.5f} +/- {:.5f}\n", mean,

t_n1 * stdev);

std::tie(mean, stdev) = mean_stdev(&gt(GlobalTally::K_ABSORPTION, 0), n);

fmt::print(" k-effective (Absorption) = {:.5f} +/- {:.5f}\n", mean,

t_n1 * stdev);

if (n > 3) {

double k_combined[2];

openmc_get_keff(k_combined);

fmt::print(" Combined k-effective = {:.5f} +/- {:.5f}\n",

k_combined[0], k_combined[1]);

}

}

std::tie(mean, stdev) = mean_stdev(&gt(GlobalTally::LEAKAGE, 0), n);

fmt::print(

" Leakage Fraction = {:.5f} +/- {:.5f}\n", mean, t_n1 * stdev);

} else {

if (mpi::master)

warning("Could not compute uncertainties -- only one "

"active batch simulated!");

if (settings::run_mode == RunMode::EIGENVALUE) {

fmt::print(" k-effective (Collision) = {:.5f}\n",

gt(GlobalTally::K_COLLISION, TallyResult::SUM) / n);

fmt::print(" k-effective (Track-length) = {:.5f}\n",

gt(GlobalTally::K_TRACKLENGTH, TallyResult::SUM) / n);

fmt::print(" k-effective (Absorption) = {:.5f}\n",

gt(GlobalTally::K_ABSORPTION, TallyResult::SUM) / n);

}

fmt::print(" Leakage Fraction = {:.5f}\n",

gt(GlobalTally::LEAKAGE, TallyResult::SUM) / n);

}

fmt::print("\n");

std::fflush(stdout);

}

//==============================================================================

const std::unordered_map<int, const char*> score_names = {

{SCORE_FLUX, "Flux"},

{SCORE_TOTAL, "Total Reaction Rate"},

{SCORE_SCATTER, "Scattering Rate"},

{SCORE_NU_SCATTER, "Scattering Production Rate"},

{SCORE_ABSORPTION, "Absorption Rate"},

{SCORE_FISSION, "Fission Rate"},

{SCORE_NU_FISSION, "Nu-Fission Rate"},

{SCORE_KAPPA_FISSION, "Kappa-Fission Rate"},

{SCORE_EVENTS, "Events"},

{SCORE_DECAY_RATE, "Decay Rate"},

{SCORE_DELAYED_NU_FISSION, "Delayed-Nu-Fission Rate"},

{SCORE_PROMPT_NU_FISSION, "Prompt-Nu-Fission Rate"},

{SCORE_INVERSE_VELOCITY, "Flux-Weighted Inverse Velocity"},

{SCORE_FISS_Q_PROMPT, "Prompt fission power"},

{SCORE_FISS_Q_RECOV, "Recoverable fission power"},

{SCORE_CURRENT, "Current"},

{SCORE_PULSE_HEIGHT, "pulse-height"},

{SCORE_IFP_TIME_NUM, "IFP lifetime numerator"},

{SCORE_IFP_BETA_NUM, "IFP delayed fraction numerator"},

{SCORE_IFP_DENOM, "IFP common denominator"},

};

//! Create an ASCII output file showing all tally results.

void write_tallies()

{

if (model::tallies.empty())

return;

// Tag tallies.out written during the forward solve of an adjoint run

const char* forward =

(FlatSourceDomain::solve_ == RandomRaySolve::FORWARD_FOR_ADJOINT)

? "forward."

: "";

// Set filename for tallies_out

std::string filename =

fmt::format("{}tallies.{}out", settings::path_output, forward);

// Open the tallies.out file.

std::ofstream tallies_out;

tallies_out.open(filename, std::ios::out | std::ios::trunc);

// Loop over each tally.

for (auto i_tally = 0; i_tally < model::tallies.size(); ++i_tally) {

const auto& tally {*model::tallies[i_tally]};

// Write header block.

std::string tally_header("TALLY " + std::to_string(tally.id_));

if (!tally.name_.empty())

tally_header += ": " + tally.name_;

fmt::print(tallies_out, "{}\n\n", header(tally_header));

if (!tally.writable_) {

fmt::print(tallies_out, " Internal\n\n");

continue;

}

// Calculate t-value for confidence intervals

double t_value = 1;

if (settings::confidence_intervals) {

auto alpha = 1 - CONFIDENCE_LEVEL;

t_value = t_percentile(1 - alpha * 0.5, tally.n_realizations_ - 1);

}

// Write derivative information.

if (tally.deriv_ != C_NONE) {

const auto& deriv {model::tally_derivs[tally.deriv_]};

switch (deriv.variable) {

case DerivativeVariable::DENSITY:

fmt::print(tallies_out, " Density derivative Material {}\n",

deriv.diff_material);

break;

case DerivativeVariable::NUCLIDE_DENSITY:

fmt::print(tallies_out,

" Nuclide density derivative Material {} Nuclide {}\n",

deriv.diff_material, data::nuclides[deriv.diff_nuclide]->name_);

break;

case DerivativeVariable::TEMPERATURE:

fmt::print(tallies_out, " Temperature derivative Material {}\n",

deriv.diff_material);

break;

default:

fatal_error(fmt::format("Differential tally dependent variable for "

"tally {} not defined in output.cpp",

tally.id_));

}

}

// Initialize Filter Matches Object

vector<FilterMatch> filter_matches;

// Allocate space for tally filter matches

filter_matches.resize(model::tally_filters.size());

// Loop over all filter bin combinations.

auto filter_iter = FilterBinIter(tally, false, &filter_matches);

auto end = FilterBinIter(tally, true, &filter_matches);

for (; filter_iter != end; ++filter_iter) {

auto filter_index = filter_iter.index_;

// Print info about this combination of filter bins. The stride check

// prevents redundant output.

int indent = 0;

for (auto i = 0; i < tally.filters().size(); ++i) {

if (filter_index % tally.strides(i) == 0) {

auto i_filt = tally.filters(i);

const auto& filt {*model::tally_filters[i_filt]};

auto& match {filter_matches[i_filt]};

fmt::print(tallies_out, "{0:{1}}{2}\n", "", indent + 1,

filt.text_label(match.i_bin_));

}

indent += 2;

}

// Loop over all nuclide and score combinations.

int score_index = 0;

for (auto i_nuclide : tally.nuclides_) {

// Write label for this nuclide bin.

if (i_nuclide == -1) {

fmt::print(tallies_out, "{0:{1}}Total Material\n", "", indent + 1);

} else {

if (settings::run_CE) {

fmt::print(tallies_out, "{0:{1}}{2}\n", "", indent + 1,

data::nuclides[i_nuclide]->name_);

} else {

fmt::print(tallies_out, "{0:{1}}{2}\n", "", indent + 1,

data::mg.nuclides_[i_nuclide].name);

}

}

// Write the score, mean, and uncertainty.

indent += 2;

for (auto score : tally.scores_) {

std::string score_name =

score > 0 ? reaction_name(score) : score_names.at(score);

double mean, stdev;

std::tie(mean, stdev) =

mean_stdev(&tally.results_(filter_index, score_index, 0),

tally.n_realizations_);

fmt::print(tallies_out, "{0:{1}}{2:<36} {3:.6} +/- {4:.6}\n", "",

indent + 1, score_name, mean, t_value * stdev);

score_index += 1;

}

indent -= 2;

}

}

}

}

} // namespace openmc