From d4f6774c172ac1e7c193fc4e89230c873d179c2b Mon Sep 17 00:00:00 2001
From: Raymaekers Luca <luca@spacehb.net>
Date: Wed, 12 Nov 2025 18:52:38 +0100
Subject: checkpoint

---
 src/haversine/haversine_generator.cpp | 138 ++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 src/haversine/haversine_generator.cpp

(limited to 'src/haversine/haversine_generator.cpp')

diff --git a/src/haversine/haversine_generator.cpp b/src/haversine/haversine_generator.cpp
new file mode 100644
index 0000000..c3f7561
--- /dev/null
+++ b/src/haversine/haversine_generator.cpp
@@ -0,0 +1,138 @@
+#include "libs/lr/lr.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#define MemoryCopy memcpy
+
+#include "listing_065.cpp"
+
+#include "haversine_random.h"
+
+enum generation_method : u32
+{
+    Method_Uniform,
+    Method_Cluster
+};
+
+int main(int ArgsCount, char *Args[], char *Env[])
+{
+    // 1. haversine_generator [uniform/cluster] [random seed] [number of pairs to generate]
+    
+    if(ArgsCount >= 4)
+    {
+        u32 Method = 0;
+        u64 RandomSeed = 0;;
+        u64 PairsCount = 0;
+        b32 Error = false;
+        
+        if(!strcmp(Args[1], "uniform"))
+        {
+            Method = Method_Uniform;
+        }
+        else if(!strcmp(Args[1], "cluster"))
+        {
+            Method = Method_Cluster;
+        }
+        else
+        {
+            Error = true;
+        }
+        
+        RandomSeed = atoll(Args[2]);
+        
+        if(RandomSeed == 0)
+        {
+            if(Args[2][0] == '0')
+            {
+                RandomSeed = 0;
+            }
+            else
+            {
+                Error = true;
+            }
+        }
+        
+        PairsCount = atoll(Args[3]);
+        if(PairsCount == 0)
+        {
+            Error = true;
+        }
+        
+        if(!Error)
+        {
+            printf("Method: %s\n"
+                   "Random seed: %lu\n"
+                   "Pairs count: %lu\n"
+                   , Args[1], RandomSeed, PairsCount);
+            
+            // Generate pairs in the following format.
+            // 
+            // {
+            //  "pairs": 
+            //   [
+            //    { "x0": ..., "y0": ..., "x1": ..., "y1": ... },
+            //    { "x0": ..., "y0": ..., "x1": ..., "y1": ... }
+            //   ]
+            // }
+            // 
+            
+            FILE *Out = fopen("out.json", "wb");
+            char *JsonHeader = 
+                "{\n"
+                " \"pairs\":\n"
+                "   [\n";
+            char *JsonFooter =
+                "   ]\n"
+                "}\n";
+            
+            fprintf(Out, "%s", JsonHeader);
+            
+            pcg64_random_t RNG = {};
+            pcg64_srandom_r(&RNG, RandomSeed, RandomSeed);
+            
+            f64 AverageSum = 0;
+            f64 TotalSum = 0;
+            for(u64 PairsIndex = 0;
+                PairsIndex < PairsCount;
+                PairsIndex++)
+            {
+                b32 LastPair = false;
+                
+                f64 X0 = RandomBetween(&RNG, -180.0, 180.0);
+                f64 Y0 = RandomBetween(&RNG, -360.0, 360.0);
+                f64 X1 = RandomBetween(&RNG, -180.0, 180.0); 
+                f64 Y1 = RandomBetween(&RNG, -360.0, 360.0);
+                
+                f64 Sum = ReferenceHaversine(X0, Y0, X1, Y1, 6372.8);
+                TotalSum += Sum;
+                
+                // NOTE(luca): A double's mantissa is 52 bits.  2^52 - 1 is 4503599627370495 which has 
+                // 16 digits.
+                fprintf(Out, 
+                        "    { \"x0\": %.15f, \"y0\": %.15f, \"x1\": %.15f, \"y1\": %.15f }\n", 
+                        X0, Y0, X1, Y1);
+                
+            }
+            AverageSum = TotalSum / (f64)PairsCount;
+            
+            fprintf(Out, "%s", JsonFooter);
+            
+            printf("Average sum: %f\n", AverageSum);
+        }
+        else
+        {
+            printf("Usage: %s [uniform/cluster] [random seed] [number of pairs to generate]\n", 
+                   Args[0]);
+        }
+    }
+    else
+    {
+        printf("Usage: %s [uniform/cluster] [random seed] [number of pairs to generate]\n", 
+               Args[0]);
+    }
+    
+    return 0;
+}
\ No newline at end of file
-- 
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