Different image bounds layout

2 files changed, 22 insertions, 15 deletions

diff --git a/aberth/aberth.cpp b/aberth/aberth.cpp
index 6936809..550760d 100644
--- a/aberth/aberth.cpp
+++ b/aberth/aberth.cpp
@@ -342,11 +342,12 @@ static vector<uint8_t> drawImage(int W, int H, const vector<int> &counts, int ma
 
 static vector<int32_t> invoke_kernel(
 		int32_t width, int32_t height,
-		double left, double top, double right, double bottom,
+		Com bottomLeft, Com topRight,
 		int32_t seed) {
 
 	futhark_context_config *config = futhark_context_config_new();
 	// futhark_context_config_select_device_interactively(config);
+	futhark_context_config_set_debugging(config, 1);
 
 	futhark_context *ctx = futhark_context_new(config);
 
@@ -364,7 +365,8 @@ static vector<int32_t> invoke_kernel(
 	check_ret(futhark_entry_main_all(
 			ctx, &dest_arr,
 			width, height,
-			left, top, right, bottom,
+			bottomLeft.real(), topRight.imag(),
+			topRight.real(), bottomLeft.imag(),
 			seed));
 
 	check_ret(futhark_context_sync(ctx));
@@ -391,9 +393,9 @@ int main(int argc, char **argv) {
 	if (argc <= 1) {
 		// tie(W, H, counts) = computeCounts();
 		W = H = 2000;
-		Com bottomLeft = Com(-1.6, -1.6);
-		Com topRight = Com(1.6, 1.6);
-		counts = invoke_kernel(W, H, bottomLeft.real(), topRight.imag(), topRight.real(), bottomLeft.imag(), 42);
+		Com bottomLeft = Com(0, -1.6);
+		Com topRight = Com(1.6, 0);
+		counts = invoke_kernel(W, H, bottomLeft, topRight, 42);
 		writeCounts(W, H, counts, "out.txt");
 	} else if (argc == 2) {
 		tie(W, H, counts) = readCounts(argv[1]);
diff --git a/aberth/aberth_kernel.fut b/aberth/aberth_kernel.fut
index fae1450..58b8838 100644
--- a/aberth/aberth_kernel.fut
+++ b/aberth/aberth_kernel.fut
@@ -128,11 +128,13 @@ let calc_index (value: f64) (left: f64) (right: f64) (steps: i32): i32 =
 
 let point_index
         (width: i32) (height: i32)
-        (top_left: complex) (bottom_right: complex)
+        (bottom_left: complex) (top_right: complex)
         (pt: complex)
         : i32 =
-    let xi = calc_index (c64.re pt) (c64.re top_left) (c64.re bottom_right) width
-    let yi = calc_index (c64.im pt) (c64.im bottom_right) (c64.im top_left) height
+    -- Range for 'yi' is reversed because image coordinates go down in the y
+    -- direction, while complex coordinates go up in the y direction
+    let xi = calc_index (c64.re pt) (c64.re bottom_left) (c64.re top_right) width
+    let yi = calc_index (c64.im pt) (c64.im top_right) (c64.im bottom_left) height
     in if 0 <= xi && xi < width && 0 <= yi && yi < height
         then width * yi + xi
         else -1
@@ -145,16 +147,19 @@ entry main_job
         : []i32 =
     -- Unnecessary to give each polynomial a different seed
     let rng = rand_engine.rng_from_seed [seed]
-    let top_left = c64.mk left top
-    let bottom_right = c64.mk right bottom
-    let indices = filter (\i -> i != -1) (flatten
+    let bottom_left = c64.mk left bottom
+    let top_right = c64.mk right top
+    let indices = flatten
             (map (\idx ->
                     let p = derbyshire_at_index idx
                     let (_, pts) = aberth.aberth p rng
-                    let indices = map (point_index width height top_left bottom_right) pts
-                    in indices)
-                 (start_index ..< start_index + num_polys)))
-    in reduce_by_index (replicate (width * height) 0) (+) 0 indices (replicate (length indices) 1)
+                    in map (point_index width height bottom_left top_right) pts)
+                 (start_index ..< start_index + num_polys))
+    let filtered = filter (\i -> i != -1) indices
+    in reduce_by_index (replicate (width * height) 0)
+                       (+) 0
+                       filtered
+                       (replicate (length filtered) 1)
 
 entry main_all
         (width: i32) (height: i32)