From df06fe6084b1c1673348050309a3a0cb99b6634f Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Sun, 3 Feb 2019 15:10:44 -0500
Subject: add cluster support to gen-data.rb, show centroids on generated png

---
 main.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 98 insertions(+), 12 deletions(-)

(limited to 'main.c')

diff --git a/main.c b/main.c
index ec62022..4d86b09 100644
--- a/main.c
+++ b/main.c
@@ -14,6 +14,11 @@
 
 #define MAX_CLUSTERS 10
 #define NUM_TESTS 100
+#define MAX_BEST 4
+
+#define IM_WIDTH 128
+#define IM_HEIGHT 128
+#define IM_STRIDE (3 * IM_WIDTH)
 
 typedef struct {
   km_rand_t rs;
@@ -24,8 +29,35 @@ typedef struct {
           cluster_size;
     size_t num_empty_clusters;
   } rows[MAX_CLUSTERS - 2];
+
+  km_set_t best[MAX_BEST];
+  size_t num_best;
 } find_t;
 
+static void
+find_each_best(
+  const find_t * const find_data,
+  void (*on_best)(const km_set_t * const, const size_t, void *),
+  void * const cb_data
+) {
+  // if the number of best sets is greater than MAX_BEST, then
+  // find_data->best is actually a ring buffer
+  const bool is_ring = find_data->num_best >= MAX_BEST;
+
+  if (!on_best) {
+    return;
+  }
+
+  // walk best sets
+  for (size_t i = 0; i < MAX_BEST; i++) {
+    // calculate set offset
+    const size_t ofs = i + (is_ring ? (find_data->num_best + 1) : 0);
+
+    // emit set
+    on_best(find_data->best + (ofs % MAX_BEST), i, cb_data);
+  }
+}
+
 static bool
 load_on_shape(
   const km_shape_t * const shape,
@@ -112,14 +144,48 @@ find_on_data(
   find_data->rows[ofs].num_empty_clusters += data->num_empty_clusters;
 }
 
+static bool
+find_on_best(
+  const float score,
+  const km_set_t * const cs,
+  void *cb_data
+) {
+  find_t *find_data = cb_data;
+
+  D("best score = %0.3f, num_clusters = %zu", score, cs->num_rows);
+
+  // get pointer to destination set
+  // (note: data->best is a ring buffer)
+  km_set_t *dst = find_data->best + (find_data->num_best % MAX_BEST);
+
+  if (find_data->num_best >= MAX_BEST) {
+    // finalize old best data set
+    // D("finalizing old best %zu", find_data->num_best);
+    km_set_fini(dst);
+  }
+
+  // copy data set to best ring buffer
+  if (!km_set_copy(dst, cs)) {
+    die("km_set_copy()");
+  }
+
+  // increment best count
+  find_data->num_best++;
+
+  // return success
+  return true;
+}
+
 // init find config
 static const km_find_cbs_t
 FIND_CBS = {
   .max_clusters = MAX_CLUSTERS,
   .num_tests    = NUM_TESTS,
+
   .on_init      = find_on_init,
   .on_fini      = find_on_fini,
   .on_data      = find_on_data,
+  .on_best      = find_on_best,
 };
 
 static float
@@ -127,9 +193,6 @@ get_score(
   const size_t ofs,
   const find_t * const find_data
 ) {
-  if (!ofs || ofs == MAX_CLUSTERS - 3) {
-    return 0;
-  }
   // const size_t num_clusters = ofs + 2;
   const float mean_distance = find_data->rows[ofs].distance / NUM_TESTS,
               mean_empty = 1.0 * find_data->rows[ofs].num_empty_clusters / NUM_TESTS;
@@ -178,22 +241,45 @@ print_csv(
   }
 }
 
-#define IM_WIDTH 128
-#define IM_HEIGHT 128
-#define IM_STRIDE (3 * IM_WIDTH)
-
 static uint8_t im_data[3 * IM_WIDTH * IM_HEIGHT];
 
+static void
+save_on_best(
+  const km_set_t * const set,
+  const size_t rank,
+  void * const cb_data
+) {
+  UNUSED(cb_data);
+
+  // convert rank to channel brightness
+  const uint8_t ch = 0x66 + (0xff - 0x66) * (1.0 * rank) / (MAX_BEST - 1);
+  const uint32_t color = (ch & 0xff) << 16;
+  // const uint32_t color = 0xff0000;
+  D("rank = %zu, color = %u", rank, color);
+
+  // draw clusters
+  km_set_draw(set, im_data, IM_WIDTH, IM_HEIGHT, 3, color);
+}
+
 static void
 save_png(
   const char * const png_path,
-  const km_set_t * const set
+  const km_set_t * const set,
+  const find_t * const find_data
 ) {
   // clear image data to white
   memset(im_data, 0xff, sizeof(im_data));
 
   // draw red points
-  km_set_draw(set, im_data, IM_WIDTH, IM_HEIGHT, 0xff0000);
+  km_set_draw(set, im_data, IM_WIDTH, IM_HEIGHT, 1, 0x000000);
+  if (!stbi_write_png(png_path, IM_WIDTH, IM_HEIGHT, 3, im_data, IM_STRIDE)) {
+    die("stbi_write_png(\"%s\")", png_path);
+  }
+
+  // draw best cluster points
+  find_each_best(find_data, save_on_best, NULL);
+
+  // save png
   if (!stbi_write_png(png_path, IM_WIDTH, IM_HEIGHT, 3, im_data, IM_STRIDE)) {
     die("stbi_write_png(\"%s\")", png_path);
   }
@@ -211,7 +297,7 @@ int main(int argc, char *argv[]) {
 
   // init find data
   find_t find_data;
-  memset(find_data.rows, 0, sizeof(find_data.rows));
+  memset(&find_data, 0, sizeof(find_t));
   km_rand_init_system(&(find_data.rs));
 
   // init data set
@@ -232,8 +318,8 @@ int main(int argc, char *argv[]) {
   // print csv
   print_csv(&find_data);
 
-  // save png of data set
-  save_png("data.png", &set);
+  // save png of normalized data set and best clusters
+  save_png("data.png", &set, &find_data);
 
   // finalize data set
   km_set_fini(&set);
-- 
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