INITIAL COMMIT

.gitignore

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+python/__pycache__/**/*
+cpp/haverscan
+cpp/haverstrtok
+data_10000000_flex.json

Makefile

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+mk_fscanf:
+	clang++ -g cpp/fscanf.cpp cpp/haversine.cpp -o cpp/haverscan
+
+run_fscanf:
+	./cpp/haverscan
+
+mk_strtok:
+	clang++ -g cpp/strtok.cpp cpp/haversine.cpp -o cpp/haverstrtok
+
+run_strtok:
+	./cpp/haverstrtok
+
+run_python_json:
+	python ./python/haversine_json.py

README.md

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+# Casey Muratori's Performance Aware Programming Course
+
+Following along Casey's course [Performance Aware Programming](https://www.computerenhance.com/s/programming-courses/archive?sort=new)

cpp/fscanf.cpp

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+#include "haversine.h"
+#include <bits/types/FILE.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define DEBUG 0
+
+#define EARTH_RADIUS_KM 6371.0
+
+#if DEBUG
+#define ITEM_COUNT 2
+#else
+#define ITEM_COUNT 10000000
+#endif
+
+struct Item {
+  double x0;
+  double y0;
+  double x1;
+  double y1;
+};
+
+int main(int argc, char *argv[]) {
+#if DEBUG
+  FILE *fp = fopen("/home/abdelrahman/Sources/dev/"
+                   "performance_aware_programming/test_data.json",
+                   "rb");
+#else
+  FILE *fp = fopen("/home/abdelrahman/Sources/dev/"
+                   "performance_aware_programming/data_10000000_flex.json",
+                   "rb");
+#endif
+
+  Item *items = (Item *)malloc(ITEM_COUNT * sizeof(Item));
+  int index = 0;
+
+  clock_t start_time = clock();
+
+  {
+    char buf[256];
+    int read = fread(buf, 1, 256, fp);
+
+    for (int i = 1; i < read; ++i) {
+      if (buf[i] == '{') {
+        fseek(fp, i, SEEK_SET);
+        break;
+      }
+    }
+  }
+
+  while (true) {
+    fscanf(fp, "{\n");
+
+    int scanned = fscanf(fp,
+                         "      \"x0\": %lf,\n      \"y0\": %lf,\n      "
+                         "\"x1\": %lf,\n      \"y1\": %lf\n    },\n    ",
+                         &(items[index].x0), &(items[index].y0),
+                         &(items[index].x1), &(items[index].y1));
+
+    if (scanned == 0) {
+      break;
+    }
+
+    ++index;
+  }
+
+  clock_t mid_time = clock();
+
+  double sum = 0.0;
+
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    sum += haversine_of_degrees(items[i].x0, items[i].y0, items[i].x1,
+                                items[i].y1, EARTH_RADIUS_KM);
+  }
+
+  double average = sum / ITEM_COUNT;
+
+  clock_t end_time = clock();
+
+  printf("Result: %.16f\n", average);
+  printf("Input = %.16f seconds\n",
+         (double)(mid_time - start_time) / CLOCKS_PER_SEC);
+  printf("Math = %.16f seconds\n",
+         (double)(end_time - mid_time) / CLOCKS_PER_SEC);
+  printf("Total = %.16f seconds\n",
+         (double)(end_time - start_time) / CLOCKS_PER_SEC);
+  printf("Throughput = %.16f haversines/second\n",
+         ITEM_COUNT / ((double)(end_time - start_time) / CLOCKS_PER_SEC));
+
+#if DEBUG
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    printf("%.16f\n%.16f\n%.16f\n%.16f\n\n", items[i].x0, items[i].y0,
+           items[i].x1, items[i].y1);
+  }
+#endif
+
+  free(items);
+
+  fclose(fp);
+
+  return 0;
+}

cpp/haversine.cpp

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+#include "haversine.h"
+#include <math.h>
+
+#define PI 3.14159265358979323845
+#define SQUARE(X) ((X) * (X))
+
+double radians(double degrees);
+
+double haversine_of_degrees(double x0, double y0, double x1, double y1,
+                            double radius) {
+  double dy = radians(y1 - y0);
+  double dx = radians(x1 - x0);
+  y0 = radians(y0);
+  y1 = radians(y1);
+
+  double root_term =
+      SQUARE(sin(dy / 2.0)) + cos(y0) * cos(y1) * SQUARE(sin(dx / 2.0));
+
+  double result = 2.0 * radius * asin(sqrt(root_term));
+
+  return result;
+}
+
+double radians(double degrees) { return (degrees * PI) / 180.0; }

cpp/haversine.h

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+#ifndef HAVERSINE_H
+#define HAVERSINE_H
+
+double haversine_of_degrees(double x0, double y0, double x1, double y1,
+                            double radius);
+
+#endif // !HAVERSINE_H

cpp/strtok.cpp

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+#include "haversine.h"
+#include <bits/types/FILE.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define DEBUG 0
+
+#define EARTH_RADIUS_KM 6371.0
+
+#if DEBUG
+#define ITEM_COUNT 2
+#else
+#define ITEM_COUNT 10000000
+#endif
+
+struct Item {
+  double x0;
+  double y0;
+  double x1;
+  double y1;
+};
+
+int main(int argc, char *argv[]) {
+#if DEBUG
+  FILE *fp = fopen("/home/abdelrahman/Sources/dev/"
+                   "performance_aware_programming/test_data.json",
+                   "rb");
+#else
+  FILE *fp = fopen("/home/abdelrahman/Sources/dev/"
+                   "performance_aware_programming/data_10000000_flex.json",
+                   "rb");
+#endif
+
+  Item *items = (Item *)malloc(ITEM_COUNT * sizeof(Item));
+  int index = 0;
+  double *elem = nullptr;
+
+  fseek(fp, 0, SEEK_END);
+
+  long length = (long)ftell(fp);
+
+  fseek(fp, 0, SEEK_SET);
+
+  char *text = (char *)malloc(length + 1);
+  memset(text, 0, length + 1);
+
+  fread(text, 1, length, fp);
+
+  clock_t start_time = clock();
+
+  const char *delim = "{}[]:,\"\n ";
+
+  char *token = strtok(text, delim);
+
+  while (token) {
+    if (strcmp(token, "x0") == 0) {
+      elem = &(items[index].x0);
+    } else if (strcmp(token, "y0") == 0) {
+      elem = &(items[index].y0);
+    } else if (strcmp(token, "x1") == 0) {
+      elem = &(items[index].x1);
+    } else if (strcmp(token, "y1") == 0) {
+      elem = &(items[index].y1);
+      ++index;
+    } else {
+      if (elem) {
+        char *end = &(token[strlen(token)]);
+        *elem = strtod(token, &end);
+        elem = nullptr;
+      }
+    }
+
+    token = strtok(NULL, delim);
+  }
+
+  clock_t mid_time = clock();
+
+  double sum = 0.0;
+
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    sum += haversine_of_degrees(items[i].x0, items[i].y0, items[i].x1,
+                                items[i].y1, EARTH_RADIUS_KM);
+  }
+
+  double average = sum / ITEM_COUNT;
+
+  clock_t end_time = clock();
+
+  printf("Result: %.16f\n", average);
+  printf("Input = %.16f seconds\n",
+         (double)(mid_time - start_time) / CLOCKS_PER_SEC);
+  printf("Math = %.16f seconds\n",
+         (double)(end_time - mid_time) / CLOCKS_PER_SEC);
+  printf("Total = %.16f seconds\n",
+         (double)(end_time - start_time) / CLOCKS_PER_SEC);
+  printf("Throughput = %.16f haversines/second\n",
+         ITEM_COUNT / ((double)(end_time - start_time) / CLOCKS_PER_SEC));
+
+#if DEBUG
+  int precision = 16;
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    printf("%.*f\n%.*f\n%.*f\n%.*f\n\n", precision, items[i].x0, precision,
+           items[i].y0, precision, items[i].x1, precision, items[i].y1);
+  }
+#endif
+
+  free(text);
+
+  free(items);
+
+  fclose(fp);
+
+  return 0;
+}

python/haversine_algorithm.py

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+from math import radians, sin, cos, sqrt, asin
+
+
+def haversine_of_degrees(x0, y0, x1, y1, radius):
+    dy = radians(y1 - y0)
+    dx = radians(x1 - x0)
+    y0 = radians(y0)
+    y1 = radians(y1)
+
+    root_term = (sin(dy / 2) ** 2) + cos(y0) * cos(y1) * (sin(dx / 2) ** 2)
+
+    result = 2 * radius * asin(sqrt(root_term))
+
+    return result

python/haversine_json.py

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+# Naive Python version of the code
+
+
+import os
+from haversine_algorithm import haversine_of_degrees
+import time
+import json
+
+
+filepath = os.path.join(
+    os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
+    "data_10000000_flex.json",
+)
+
+with open(filepath, "r") as json_file:
+    start_time = time.time()
+    json_input = json.load(json_file)
+    mid_time = time.time()
+
+
+earth_radius_km = 6371
+sum = 0
+count = 0
+
+for pair in json_input["pairs"]:
+    sum += haversine_of_degrees(
+        pair["x0"], pair["y0"], pair["x1"], pair["y1"], earth_radius_km
+    )
+
+    count += 1
+
+average = sum / count
+
+end_time = time.time()
+
+print(f"Result: {average}")
+print(f"Input = {mid_time - start_time} seconds")
+print(f"Math = {end_time - mid_time} seconds")
+print(f"Total = {end_time - start_time} seconds")
+print(f"Throughput = {count / (end_time - start_time)} haversines/second")

test_data.json

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+{
+  "pairs": [
+    {
+      "x0": -4.618412003630709,
+      "y0": 135.8153583196389,
+      "x1": -12.383220322958223,
+      "y1": 85.20071945064029
+    },
+    {
+      "x0": 47.817641963713584,
+      "y0": 111.40590001495877,
+      "x1": -34.52607922832944,
+      "y1": -127.52991299863771
+    }
+	]
+}