diff --git a/include/gp/math.hpp b/include/gp/math.hpp
index 8a0910b..9d5661e 100644
--- a/include/gp/math.hpp
+++ b/include/gp/math.hpp
@@ -13,9 +13,14 @@ namespace gp {
 	T lerp(T input, T low, T high) {
 		return low + (high - low) * input;
 	}
+	template<typename T>
+	T lextrap(T input, T low, T high) {
+		return (input - low) / (high - low);
+	}
 
 	template<typename T, size_t fixed_passes = 16>
 	T fixed_sqrt(T value) {
+		gp_config::assertion(value >= 0, "trying to compute square root of negative number");
 		if(value == 0) return 0;
 		T ret = value / 2;
 		T tmp;
@@ -30,6 +35,7 @@ namespace gp {
 
 	template<typename T, size_t cap_passes = 16>
 	T epsilon_sqrt(T value) {
+		gp_config::assertion(value >= 0, "trying to compute square root of negative number");
 		if(value == 0) return 0;
 		T ret = value / 2;
 		T tmp;
@@ -52,6 +58,7 @@ namespace gp {
 
 	template<typename T, size_t cap_passes = 16>
 	T stable_sqrt(T value) {
+		gp_config::assertion(value >= 0, "trying to compute square root of negative number");
 		if(value == 0) return 0;
 		T ret = value / 2;
 		T tmp;