utilized fabs to fix the bug

Author: Piotr Maślanka

opensfm/src/geometry/triangulation.h

@@ -7,6 +7,7 @@
 #include <fstream>
 #include <iostream>
 #include <string>
+#include <math.h>
 
 double AngleBetweenVectors(const Eigen::Vector3d &u, const Eigen::Vector3d &v);
 
@@ -68,7 +69,7 @@ std::pair<bool, Eigen::Matrix<T, 3, 1>> TriangulateTwoBearingsMidpointSolve(
 
   const T eps = T(1e-30);
   const T det = A.determinant();
-  if ((det < eps) && (det > -eps)) {
+  if (fabs(det) < eps) {
     return std::make_pair(false, Eigen::Matrix<T, 3, 1>());
   }
   const auto lambdas = A.inverse() * b;