save Tmat in binary format

pkg/rrc/helper.go

@@ -0,0 +1,26 @@
+package rrc
+
+func searchVL(V []float64, Sik float64) int {
+	left, right := 0, len(V)-2
+
+	// if Sik < V[0] || Sik > V[len(V)-1] {
+	// 	return -1
+	// }
+
+	for left <= right {
+		mid := left + (right-left)/2
+		// Check if Sik is between V[mid] and V[mid+1]
+		if V[mid]-1e-6 <= Sik && Sik <= V[mid+1]+1e-6 {
+			return mid
+		} else if Sik < V[mid] {
+			right = mid - 1
+		} else if Sik == V[mid] {
+			return mid
+		} else {
+			left = mid + 1
+		}
+	}
+
+	// Return -1 if no such position is found
+	return -1
+}