fix typo

MathLib/InterpolationAlgorithms/PiecewiseLinearInterpolation.cpp

@@ -68,7 +68,7 @@ double PiecewiseLinearInterpolation::getValue(double pnt_to_interpolate) const
            _values_at_supp_pnts[interval_idx];
 }
 
-double PiecewiseLinearInterpolation::GetDerivative(
+double PiecewiseLinearInterpolation::getDerivative(
     double const pnt_to_interpolate) const
 {
     if (pnt_to_interpolate < _supp_pnts.front() ||
@@ -84,18 +84,18 @@ double PiecewiseLinearInterpolation::GetDerivative(
     // interval_idx = interval_max - 1 - interval_idx;
     if (interval_idx > 1 && interval_idx < _supp_pnts.size() - 2)
     {
-        double const slope_right =
+        double const tangent_right =
             (_values_at_supp_pnts[interval_idx] -
              _values_at_supp_pnts[interval_idx + 2]) /
             (_supp_pnts[interval_idx] - _supp_pnts[interval_idx + 2]);
-        double const slope_left =
+        double const tangent_left =
             (_values_at_supp_pnts[interval_idx - 1] -
              _values_at_supp_pnts[interval_idx + 1]) /
             (_supp_pnts[interval_idx - 1] - _supp_pnts[interval_idx + 1]);
         double const w =
             (pnt_to_interpolate - _supp_pnts[interval_idx + 1]) /
             (_supp_pnts[interval_idx] - _supp_pnts[interval_idx + 1]);
-        return (1. - w) * slope_right + w * slope_left;
+        return (1. - w) * tangent_right + w * tangent_left;
     }
     else
     {

MathLib/InterpolationAlgorithms/PiecewiseLinearInterpolation.h

@@ -70,13 +70,13 @@ public:
      * \f$x_{\max} = \max_{1 \le j \le n} x_j\f$. when points are located
      * outside of this interval
      * the derivative is set to 0
-     * \attention if the points is located between the first and second points
+     * \attention if the points are located between the first and second points
      * (or last and second to last point), the derivative is calculated by
      * simple linear interpolation
      * otherwise, it is calculated by second order of interpolation with central
      * difference
      */
-    double GetDerivative(double pnt_to_interpolate) const;
+    double getDerivative(double const pnt_to_interpolate) const;
 
 private:
     std::vector<double> _supp_pnts;

Tests/MathLib/TestPiecewiseLinearInterpolation.cpp

@@ -139,14 +139,14 @@ TEST(MathLibInterpolationAlgorithms, PiecewiseLinearInterpolationDerivative)
     // Interpolation
     for (std::size_t k(0); k < size - 1; ++k)
     {
-        ASSERT_NEAR(1 + 2 * k, interpolation.GetDerivative(k + 0.5),
+        ASSERT_NEAR(1 + 2 * k, interpolation.getDerivative(k + 0.5),
                     std::numeric_limits<double>::epsilon());
     }
 
     // Extrapolation
-    ASSERT_NEAR(0, interpolation.GetDerivative(-1),
+    ASSERT_NEAR(0, interpolation.getDerivative(-1),
                 std::numeric_limits<double>::epsilon());
     // Extrapolation
-    ASSERT_NEAR(0, interpolation.GetDerivative(1001),
+    ASSERT_NEAR(0, interpolation.getDerivative(1001),
                 std::numeric_limits<double>::epsilon());
 }