[Project] Support callback function for train

contrib/kann/kann.c

@@ -846,7 +846,10 @@ float kann_grad_clip(float thres, int n, float *g)
  *** @@XY: simpler API for network with a single input/output ***
  ****************************************************************/
 
-int kann_train_fnn1(kann_t *ann, float lr, int mini_size, int max_epoch, int max_drop_streak, float frac_val, int n, float **_x, float **_y)
+int kann_train_fnn1(kann_t *ann, float lr, int mini_size, int max_epoch,
+					int max_drop_streak, float frac_val, int n,
+					float **_x, float **_y,
+					kann_train_cb cb, void *ud)
 {
 	int i, j, *shuf, n_train, n_val, n_in, n_out, n_var, n_const, drop_streak = 0, min_set = 0;
 	float **x, **y, *x1, *y1, *r, min_val_cost = FLT_MAX, *min_x, *min_c;
@@ -907,7 +910,9 @@ int kann_train_fnn1(kann_t *ann, float lr, int mini_size, int max_epoch, int max
 			n_proc += ms;
 		}
 		if (n_val > 0) val_cost /= n_val;
-		if (kann_verbose >= 3) {
+		if (cb) {
+			cb(i + 1, train_cost, val_cost, ud);
+#if 0
 			fprintf(stderr, "epoch: %d; training cost: %g", i+1, train_cost);
 			if (n_train_base) fprintf(stderr, " (class error: %.2f%%)", 100.0f * n_train_err / n_train);
 			if (n_val > 0) {
@@ -915,6 +920,7 @@ int kann_train_fnn1(kann_t *ann, float lr, int mini_size, int max_epoch, int max
 				if (n_val_base) fprintf(stderr, " (class error: %.2f%%)", 100.0f * n_val_err / n_val);
 			}
 			fputc('\n', stderr);
+#endif
 		}
 		if (i >= max_drop_streak && n_val > 0) {
 			if (val_cost < min_val_cost) {