From f02c73a1cde15f55eac0ee2ecd0a10b6778d8b6c Mon Sep 17 00:00:00 2001
From: Franklin Wei <me@fwei.tk>
Date: Sun, 3 Feb 2019 17:51:30 -0500
Subject: Add field output (suitable for gnuplot)

---
 test.cpp | 49 +++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 6 deletions(-)

(limited to 'test.cpp')

diff --git a/test.cpp b/test.cpp
index 8d20829..92c9272 100644
--- a/test.cpp
+++ b/test.cpp
@@ -1,9 +1,12 @@
 #include <cmath>
 #include <iostream>
 #include "curve.h"
+using namespace std;
 
 vec3 integrand(vec3 s, vec3 ds)
 {
+    cout << "point " << s << "ds = " << ds << endl;
+
     return ds;
 }
 
@@ -21,16 +24,50 @@ vec3 dB(vec3 s, vec3 ds)
     return ds.cross(rnorm) / r2;
 }
 
+//Arc loop(vec3(0, 0, 0), vec3(0, 1, 0), vec3(1, 0, 0), M_PI * 2);
+//Spiral loop(vec3(0, 0, 0), vec3(0, 1, 0), vec3(1, 0, 0), M_PI * 2 * 10, 1);
+LineSegment loop(vec3(0, 0, 0), vec3(10, 0, 0));
+
+/* dump the field (gnuplot format) at z = 0 */
+/* requires x0 < x1, y0 < y1 */
+void dump_field(double x0, double y0, double z0, double x1, double y1, double z1)
+{
+    const double delta = .2;
+
+    for(double z = z0; z <= z1; z += delta)
+        for(double y = y0; y <= y1; y += delta)
+            for(double x = x0; x <= x1; x += delta)
+            {
+                point = vec3(x, y, z);
+                const double U0 = 4e-7 * M_PI;
+                const double I = 1;
+
+                vec3 B = loop.integrate(dB, 1e-1) * U0 * I;
+
+                if(B.magnitude() > 1e-8)
+                {
+                    B=B.normalize() / 10;
+                    cout << point[0] << " " << point[1] << " " << point[2] << " ";
+                    cout << B[0] << " " << B[1] << " " << B[2] << endl;
+                }
+            }
+}
+
 int main()
 {
-    LineSegment wire(vec3(0, -100, 0), vec3(0, 100, 0));
+    //LineSegment wire(vec3(0, -100, 0), vec3(0, 100, 0));
+
+    //std::cout << "length = " << loop.integrate(integrand, 1e-2) << endl;
+
+    //vec3 dx = .01;
 
-    vec3 dx = .001;
+    //point = 0;
 
-    point = .01;
+    //double I = 1;
 
-    double I = 1;
+    //for(int i = 0; i < 1000; i++, point += dx)
+    //std::cout << point[0] << " " << U0 / ( 4 * M_PI ) * loop.integrate(dB, 1e-2)[0] << endl;
 
-    for(int i = 0; i < 100; i++, point += dx)
-        std::cout << point[0] << " " << wire.integrate(dB, 1e-2)[2] << endl;
+    dump_field(-1, -1.5, -1.5,
+               11, 1.5, 1.5);
 }
-- 
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