Change barometer conversion code to shrink conversion table

1 files changed, 75 insertions, 0 deletions

diff --git a/src/ao_convert_test.c b/src/ao_convert_test.c
new file mode 100644
index 00000000..e2c28b73
--- /dev/null
+++ b/src/ao_convert_test.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright © 2010 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <stdint.h>
+#define AO_CONVERT_TEST
+#include "ao_host.h"
+#include "ao_convert.c"
+
+#define STEP	1
+
+static inline i_abs(int i) { return i < 0 ? -i : i; }
+
+main ()
+{
+	int	i;
+	int16_t p_to_a, p_to_a_to_p;
+	int16_t a_to_p, a_to_p_to_a;
+	int max_p_error = 0, max_p_error_p = -1;
+	int max_a_error = 0, max_a_error_a = -1;
+	int p_error;
+	int a_error;
+	int ret = 0;
+
+	for (i = 0; i < 32767 + STEP; i += STEP) {
+		if (i > 32767)
+			i = 32767;
+		p_to_a = ao_pres_to_altitude(i);
+		p_to_a_to_p = ao_altitude_to_pres(p_to_a);
+		p_error = i_abs(p_to_a_to_p - i);
+		if (p_error > max_p_error) {
+			max_p_error = p_error;
+			max_p_error_p = i;
+		}
+//		printf ("pres %d alt %d pres %d\n",
+//			i, p_to_a, p_to_a_to_p);
+	}
+	for (i = -1578; i < 15835 + STEP; i += STEP) {
+		if (i > 15835)
+			i = 15835;
+		a_to_p = ao_altitude_to_pres(i);
+		a_to_p_to_a = ao_pres_to_altitude(a_to_p);
+		a_error = i_abs(a_to_p_to_a - i);
+		if (a_error > max_a_error) {
+			max_a_error = a_error;
+			max_a_error_a = i;
+		}
+//		printf ("alt %d pres %d alt %d\n",
+//			i, a_to_p, a_to_p_to_a);
+	}
+	if (max_p_error > 2) {
+		printf ("max p error %d at %d\n", max_p_error,
+			max_p_error_p);
+		ret++;
+	}
+	if (max_a_error > 1) {
+		printf ("max a error %d at %d\n", max_a_error,
+			max_a_error_a);
+		ret++;
+	}
+	return ret;
+}