Apply compile time optimisations

2024-04-07 13:06:49 +02:00 · 2024-04-07 13:06:49 +02:00 · 33c18dbefa
commit 33c18dbefa
parent 29b5365918
4 changed files with 284 additions and 13 deletions
--- a/versions/comptime_constants.c
+++ b/versions/comptime_constants.c
@ -0,0 +1,100 @@
+#include <stdint.h>
+#include <stdlib.h>
+
+#define DCT_SIZE 8
+#define TOTAL_DCT_BLOCKS 100
+
+#define element_t int16_t
+#define real_t double
+
+#define DCT_COS_TABLE_SIZE 32
+// DCT_COS_TABLE[i] = cos(i * PI / (2 * DCT_SIZE))
+#define DCT_COS_TABLE (double[DCT_COS_TABLE_SIZE]) { \
+    1, 0.980785, 0.92388, 0.83147, 0.707107, 0.55557, 0.382683, \
+    0.19509, 0, -0.19509, -0.382683, -0.55557, -0.707107, -0.83147, \
+    -0.92388, -0.980785, -1, -0.980785, -0.92388, -0.83147, -0.707107, \
+    -0.55557, -0.382683, -0.19509, 0, 0.19509, 0.382683, 0.55557, \
+    0.707107, 0.83147, 0.92388, 0.980785 }
+
+#define INV_SQRTDCT_SIZE (real_t) 0.3535533906 
+#define SQRT2_INV_SQRTDCT (real_t) 0.5 
+
+void dct_2d(element_t** matrix_in, element_t** matrix_out) {
+    real_t cu, cv, sum, cos_u, cos_v;
+    int u, v, i, j;
+
+    for (u = 0; u < DCT_SIZE; u++) {
+        cu = u == 0 ? INV_SQRTDCT_SIZE : SQRT2_INV_SQRTDCT;
+        for (v = 0; v < DCT_SIZE; v++) {
+            cv = v == 0 ? INV_SQRTDCT_SIZE : SQRT2_INV_SQRTDCT; 
+            sum = 0;
+            for (i = 0; i < DCT_SIZE; i++) {
+                cos_u = DCT_COS_TABLE[((2 * i + 1) * u) % DCT_COS_TABLE_SIZE];
+                for (j = 0; j < DCT_SIZE; j++) { 
+                    cos_v = DCT_COS_TABLE[((2 * j + 1) * v) % DCT_COS_TABLE_SIZE];
+                    sum += matrix_in[i][j] * cos_u * cos_v; 
+                }
+            }
+            matrix_out[u][v] = cu * cv * sum;
+        }
+    }
+}
+
+
+void populate_mock_matrices(element_t*** mock_matrices) {
+    for (long i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        for (int j = 0; j < DCT_SIZE; j++) {
+            for (int k = 0; k < DCT_SIZE; k++) {
+                mock_matrices[i][j][k] = j + k;
+            }
+        }
+    }
+}
+
+
+element_t*** generate_mock_matrices() {
+    element_t ***mock_matrices = (element_t ***) malloc(TOTAL_DCT_BLOCKS * sizeof(element_t**));
+    for (int i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        mock_matrices[i] = (element_t **) malloc(DCT_SIZE * sizeof(element_t*));
+        for (int j = 0; j < DCT_SIZE; j++) {
+            mock_matrices[i][j] = (element_t *) malloc(DCT_SIZE * sizeof(element_t));              
+        }
+    }
+
+    populate_mock_matrices(mock_matrices);
+    return mock_matrices;
+}
+
+void free_mock_matrices(element_t*** mock_matrices, element_t** matrix_out) {
+    for (int i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        for (int j = 0; j < DCT_SIZE; j++) {
+            free(mock_matrices[i][j]);
+        }
+        free(mock_matrices[i]);
+    }
+    free(mock_matrices);
+
+}
+
+int main() {
+    element_t ***mock_matrices = generate_mock_matrices();
+    int i;
+
+    element_t** matrix_out = (element_t **) malloc(DCT_SIZE * sizeof(element_t*));
+    for (i = 0; i < DCT_SIZE; i++) {
+        matrix_out[i] = (element_t *) malloc(DCT_SIZE * sizeof(element_t));
+    }
+
+    for(i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        dct_2d(mock_matrices[i], matrix_out);
+    }
+
+    free_mock_matrices(mock_matrices, matrix_out);
+
+    for (i = 0; i < DCT_SIZE; i++) {
+        free(matrix_out[i]);
+    }
+    free(matrix_out);
+
+    return 0;
+}
--- a/versions/naive.c
+++ b/versions/naive.c
@ -0,0 +1,90 @@
+#include <math.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define DCT_SIZE 8
+#define TOTAL_DCT_BLOCKS 100
+
+#define PI 3.14159265358979323846
+
+#define element_t int16_t
+#define real_t double
+
+void dct_2d(element_t** matrix_in, element_t** matrix_out) {
+    real_t cu, cv, sum;
+    int u, v, i, j;
+
+    for (u = 0; u < DCT_SIZE; u++) {
+        for (v = 0; v < DCT_SIZE; v++) {
+            cu = u == 0 ? 1 / sqrt(DCT_SIZE) : sqrt(2) / sqrt(DCT_SIZE);
+            cv = v == 0 ? 1 / sqrt(DCT_SIZE) : sqrt(2) / sqrt(DCT_SIZE); 
+
+            sum = 0;
+            for (i = 0; i < DCT_SIZE; i++) {
+                for (j = 0; j < DCT_SIZE; j++) {
+                    sum += matrix_in[i][j] * cos((2 * i + 1) * u * PI / (2 * DCT_SIZE)) * cos((2 * j + 1) * v * PI / (2 * DCT_SIZE));
+                }
+            }
+            matrix_out[u][v] = cu * cv * sum;
+        }
+    }
+}
+
+
+void populate_mock_matrices(element_t*** mock_matrices) {
+    for (long i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        for (int j = 0; j < DCT_SIZE; j++) {
+            for (int k = 0; k < DCT_SIZE; k++) {
+                mock_matrices[i][j][k] = j + k;
+            }
+        }
+    }
+}
+
+
+element_t*** generate_mock_matrices() {
+    element_t ***mock_matrices = (element_t ***) malloc(TOTAL_DCT_BLOCKS * sizeof(element_t**));
+    for (int i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        mock_matrices[i] = (element_t **) malloc(DCT_SIZE * sizeof(element_t*));
+        for (int j = 0; j < DCT_SIZE; j++) {
+            mock_matrices[i][j] = (element_t *) malloc(DCT_SIZE * sizeof(element_t));              
+        }
+    }
+
+    populate_mock_matrices(mock_matrices);
+
+    return mock_matrices;
+}
+
+void free_mock_matrices(element_t*** mock_matrices, element_t** matrix_out) {
+    for (int i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        for (int j = 0; j < DCT_SIZE; j++) {
+            free(mock_matrices[i][j]);
+        }
+        free(mock_matrices[i]);
+    }
+    free(mock_matrices);
+
+}
+
+int main() {
+    element_t ***mock_matrices = generate_mock_matrices();
+
+    element_t** matrix_out = (element_t **) malloc(DCT_SIZE * sizeof(element_t*));
+    for (int i = 0; i < DCT_SIZE; i++) {
+        matrix_out[i] = (element_t *) malloc(DCT_SIZE * sizeof(element_t));
+    }
+
+    for(long i = 0; i < TOTAL_DCT_BLOCKS; i++) {
+        dct_2d(mock_matrices[i], matrix_out);
+    }
+
+    free_mock_matrices(mock_matrices, matrix_out);
+
+    for (int i = 0; i < DCT_SIZE; i++) {
+        free(matrix_out[i]);
+    }
+    free(matrix_out);
+
+    return 0;
+}