From 07fe15f8630700656cbaaca63fc54c0cdc1442d4 Mon Sep 17 00:00:00 2001
From: mckay <wchpub@163.com>
Date: Sun, 5 Oct 2025 20:47:26 +0800
Subject: [PATCH] =?UTF-8?q?fix(quadrature):=20optimize=20Gauss-Legendre=20?=
 =?UTF-8?q?and=20tanh-sinh=20integration=20calculations=EF=BC=8Csupport=20?=
 =?UTF-8?q?integral=20over=20[a,=20b]?=
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---
 surface_integral/include/quadrature.hpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/surface_integral/include/quadrature.hpp b/surface_integral/include/quadrature.hpp
index 243f815..ba69ae6 100644
--- a/surface_integral/include/quadrature.hpp
+++ b/surface_integral/include/quadrature.hpp
@@ -3,25 +3,27 @@
 #include "GL_integrator.hpp"
 #include "TS_integrator.hpp"
 
-// 高斯-勒让德一维积分：积分区间 [a, b]
+// Gauss-Legendre quadrature for 1D integral over interval [a, b]
 template<typename Func>
 double gauss_integrate_1D(double a, double b, Func&& func, int q) {
     double sum = 0.0;
+    double length = b - a;
     for (int i = 0; i < q; ++i) {
-        double x = GLIntegrator<double>::x(q, i, a, b);
-        double w = GLIntegrator<double>::w(q, i, a, b);
+        double x = a + length * GLIntegrator<double>::x(q, i);
+        double w = length * GLIntegrator<double>::w(q, i);
         sum += w * func(x);
     }
     return sum;
 }
 
-// tanh-sinh 一维积分：积分区间 [a, b]
+// Tanh-sinh quadrature for 1D integral over [a, b]
 template<typename Func>
 double tanh_sinh_integrate_1D(double a, double b, Func&& func, int q) {
     double result = 0.0;
+    double length = b - a;
     for (int i = 0; i < q; ++i) {
-        double x = TSIntegrator<double>::x(q, i, a, b);
-        double w = TSIntegrator<double>::w(q, i, a, b);
+        double x = a + length * TSIntegrator<double>::x(q, i, a, b);
+        double w = length * TSIntegrator<double>::w(q, i, a, b);
         result += w * func(x);
     }
     return result;