1 files changed, 34 insertions, 0 deletions
diff --git a/src/update_beta.c b/src/update_beta.c
new file mode 100644
index 0000000..4c1bf65
--- /dev/null
+++ b/src/update_beta.c
@@ -0,0 +1,34 @@
+
+#include "fracture.h"
+
+double f(double damage) {
+	assert(damage <= 1 && damage >= 0);
+	return sqrt(1 - sqrt(1 - damage));
+	//	return 0.5 - 0.68182 * (0.5 - damage);
+}
+
+double update_beta(double beta, unsigned int width, const double *stress,
+									 const double *damage, double bound_total) {
+
+	double total = 0;
+	unsigned int num_totaled = 0;
+
+	for (unsigned int i = 0; i < pow(width, 2); i++) {
+		unsigned int stress_index =
+				width / 4 + (width / 4 + (i / width) / 2) * width + (i % width) / 2;
+		double outer_damage = f(pow(fabs(stress[i]), beta));
+		double inner_stress = fabs(2 * stress[stress_index] / bound_total);
+
+		if (outer_damage > 0 && inner_stress > 0 && inner_stress != 1) {
+			total += log(outer_damage) / log(inner_stress);
+			num_totaled++;
+		}
+	}
+
+	assert(num_totaled > 0);
+	assert(total == total);
+
+	double new_beta = total / num_totaled;
+
+	return new_beta;
+}