one output (of course), Pade approximant of logistic for activation

3 files changed, 14 insertions, 16 deletions

diff --git a/include/ct1973.c b/include/ct1975.c
index 592b0b1..760fcd1 100644
--- a/include/ct1973.c
+++ b/include/ct1975.c
@@ -1,9 +1,8 @@
-#include "ct1973.h"
+#include "ct1975.h"
 
 float flattened[CONV_NUM+2];
 float dense1[DENSE1_NUM];
 float dense2[DENSE2_NUM];
-float output[OUTPUT_NUM];
 
 #define RELU(x) ((x) = ((x)<0)?0:(x))
 
@@ -76,14 +75,15 @@ evaluate_black_win(void) {
 	/* ------------- *
 	 *  Output layer *
 	 * ------------- */
-	float norm = 0;
-	for (uint8_t out = 0; out < OUTPUT_NUM; out++) {
-		output[out] = output_biases[out];
-		for (uint8_t d2 = 0; d2 < DENSE2_NUM; d2++) {
-			output[out] += dense2[d2]*output_weights[out][d2];
-		}
-		output[out] = exp(output[out]);
-		norm += output[out];
+	float output = output_bias;
+	for (uint8_t d2 = 0; d2 < DENSE2_NUM; d2++) {
+		output += dense2[d2]*output_weights[d2];
 	}
-	return output[1]/norm;
+
+	// Truncated Pade approximant of logistic function
+	output = (12.0+output+50.0*output/(output*output+10.0))/24.0;
+	if (output > 1.0) return 1.0;
+	else if (output < 0.0) return 0.0;
+
+	return output;
 }
diff --git a/include/ct1973.h b/include/ct1975.h
index 6350ff3..79c20d2 100644
--- a/include/ct1973.h
+++ b/include/ct1975.h
@@ -1,5 +1,4 @@
 #include <stdint.h>
-#include <math.h>
 #include "tak.h"
 #include "weights.h"
 
diff --git a/include/weights.h b/include/weights.h
index 3c83010..18079ba 100644
--- a/include/weights.h
+++ b/include/weights.h
@@ -5,8 +5,7 @@
 #define CONV_NUM   (KERN_NUM * KERN_OSIZE * KERN_OSIZE) // 108
 
 #define DENSE1_NUM 9
-#define DENSE2_NUM 8
-#define OUTPUT_NUM 2
+#define DENSE2_NUM 9
 
 extern const float conv2d_weights[KERN_NUM][KERN_SIZE][KERN_SIZE][KERN_CHAN];
 extern const float conv2d_biases[KERN_NUM];
@@ -14,5 +13,5 @@ extern const float dense1_weights[DENSE1_NUM][CONV_NUM+2];
 extern const float dense1_biases[DENSE1_NUM];
 extern const float dense2_weights[DENSE2_NUM][DENSE1_NUM];
 extern const float dense2_biases[DENSE2_NUM];
-extern const float output_weights[OUTPUT_NUM][DENSE2_NUM];
-extern const float output_biases[2];
+extern const float output_weights[DENSE2_NUM];
+extern const float output_bias;