1 files changed, 13 insertions, 14 deletions

diff --git a/extern/ceres/internal/ceres/polynomial.cc b/extern/ceres/internal/ceres/polynomial.cc
index 20812f4de81..96267aae97f 100644
--- a/extern/ceres/internal/ceres/polynomial.cc
+++ b/extern/ceres/internal/ceres/polynomial.cc
@@ -37,7 +37,7 @@
 
 #include "Eigen/Dense"
 #include "ceres/function_sample.h"
-#include "ceres/internal/port.h"
+#include "ceres/internal/export.h"
 #include "glog/logging.h"
 
 namespace ceres {
@@ -128,12 +128,12 @@ void FindLinearPolynomialRoots(const Vector& polynomial,
                                Vector* real,
                                Vector* imaginary) {
   CHECK_EQ(polynomial.size(), 2);
-  if (real != NULL) {
+  if (real != nullptr) {
     real->resize(1);
     (*real)(0) = -polynomial(1) / polynomial(0);
   }
 
-  if (imaginary != NULL) {
+  if (imaginary != nullptr) {
     imaginary->setZero(1);
   }
 }
@@ -147,16 +147,16 @@ void FindQuadraticPolynomialRoots(const Vector& polynomial,
   const double c = polynomial(2);
   const double D = b * b - 4 * a * c;
   const double sqrt_D = sqrt(fabs(D));
-  if (real != NULL) {
+  if (real != nullptr) {
     real->setZero(2);
   }
-  if (imaginary != NULL) {
+  if (imaginary != nullptr) {
     imaginary->setZero(2);
   }
 
   // Real roots.
   if (D >= 0) {
-    if (real != NULL) {
+    if (real != nullptr) {
       // Stable quadratic roots according to BKP Horn.
       // http://people.csail.mit.edu/bkph/articles/Quadratics.pdf
       if (b >= 0) {
@@ -171,11 +171,11 @@ void FindQuadraticPolynomialRoots(const Vector& polynomial,
   }
 
   // Use the normal quadratic formula for the complex case.
-  if (real != NULL) {
+  if (real != nullptr) {
     (*real)(0) = -b / (2.0 * a);
     (*real)(1) = -b / (2.0 * a);
   }
-  if (imaginary != NULL) {
+  if (imaginary != nullptr) {
     (*imaginary)(0) = sqrt_D / (2.0 * a);
     (*imaginary)(1) = -sqrt_D / (2.0 * a);
   }
@@ -240,14 +240,14 @@ bool FindPolynomialRoots(const Vector& polynomial_in,
   }
 
   // Output roots
-  if (real != NULL) {
+  if (real != nullptr) {
     *real = solver.eigenvalues().real();
   } else {
-    LOG(WARNING) << "NULL pointer passed as real argument to "
+    LOG(WARNING) << "nullptr pointer passed as real argument to "
                  << "FindPolynomialRoots. Real parts of the roots will not "
                  << "be returned.";
   }
-  if (imaginary != NULL) {
+  if (imaginary != nullptr) {
     *imaginary = solver.eigenvalues().imag();
   }
   return true;
@@ -304,7 +304,7 @@ void MinimizePolynomial(const Vector& polynomial,
 
   const Vector derivative = DifferentiatePolynomial(polynomial);
   Vector roots_real;
-  if (!FindPolynomialRoots(derivative, &roots_real, NULL)) {
+  if (!FindPolynomialRoots(derivative, &roots_real, nullptr)) {
     LOG(WARNING) << "Unable to find the critical points of "
                  << "the interpolating polynomial.";
     return;
@@ -376,8 +376,7 @@ void MinimizeInterpolatingPolynomial(const vector<FunctionSample>& samples,
                                      double* optimal_value) {
   const Vector polynomial = FindInterpolatingPolynomial(samples);
   MinimizePolynomial(polynomial, x_min, x_max, optimal_x, optimal_value);
-  for (int i = 0; i < samples.size(); ++i) {
-    const FunctionSample& sample = samples[i];
+  for (const auto& sample : samples) {
     if ((sample.x < x_min) || (sample.x > x_max)) {
       continue;
     }