1 files changed, 77 insertions, 0 deletions
diff --git a/benchmarks/sobel/sobel.c b/benchmarks/sobel/sobel.c
new file mode 100644
index 0000000..e40e066
--- /dev/null
+++ b/benchmarks/sobel/sobel.c
@@ -0,0 +1,77 @@
+// source: https://github.com/LegUpComputing/legup-examples/tree/master/tutorials/sobel
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "input.h"
+#include "output.h"
+
+#define WIDTH 512
+#define HEIGHT 512
+
+void sobel_filter(unsigned char input[][WIDTH],
+                  unsigned char output[][WIDTH]) {
+    int i, j;
+    int m, n;
+
+    int gx_sum, gy_sum, sum;
+
+    int gx[3][3] = {{-1, 0, 1},
+                    {-2, 0, 2},
+                    {-1, 0, 1}};
+
+    int gy[3][3] = {{ 1,  2,  1},
+                    { 0,  0,  0},
+                    {-1, -2, -1}};
+
+    for (i = 0; i < HEIGHT; i++) {
+        for (j = 0; j < WIDTH; j++) {
+            sum = 0;
+            int outofbounds = 0;
+            outofbounds |= (i < 1) | (i > (HEIGHT - 2));
+            outofbounds |= (j < 1) | (j > (WIDTH - 2));
+
+            gx_sum = 0;
+            gy_sum = 0;
+            for (m = -1; m <= 1; m++) {
+                for (n = -1; n <= 1; n++) {
+                    gx_sum += (outofbounds) ? 0 :
+                        ((int)input[i + m][j + n]) * gx[m + 1][n + 1];
+                    gy_sum += (outofbounds) ? 0 :
+                        ((int)input[i + m][j + n]) * gy[m + 1][n + 1];
+                }
+            }
+
+            gx_sum = (gx_sum < 0) ? -gx_sum : gx_sum;
+            gy_sum = (gy_sum < 0) ? -gy_sum : gy_sum;
+
+            sum = gx_sum + gy_sum;
+            sum = (sum > 255) ? 255 : sum;
+
+            output[i][j] = (unsigned int)sum;
+        }
+    }
+}
+
+int main()
+{
+    unsigned char sobel_output[HEIGHT][WIDTH];
+
+    sobel_filter(elaine_512_input, sobel_output);
+
+    int result = 0;
+    int i, j;
+
+    for(i = 0; i < HEIGHT; i++) {
+        for(j = 0; j < WIDTH; j++){
+            if( sobel_output[i][j] != elaine_512_golden_output[i][j])
+                result++;
+        }
+    }
+
+    if (!result)
+        printf("PASS!\n");
+    else
+        printf("FAIL with %d differences\n", result);
+
+    return result;
+}