fix test

tests/include/igl/cotmatrix.cpp

@@ -49,22 +49,34 @@ TEST_CASE("cotmatrix: cube", "[igl]")
   igl::cotmatrix(V,F,L1);
   REQUIRE (L1.rows() == V.rows());
   REQUIRE (L1.cols() == V.rows());
-  for(int f = 0;f<L1.rows();f++)
-  {
+//// This is hitting an Eigen bug.  https://github.com/libigl/libigl/pull/1064
+//  for(int f = 0;f<L1.rows();f++)
+//  {
+//#ifdef IGL_EDGE_LENGTHS_SQUARED_H
+//    //Hard assert if we have edge_lenght_squared
+//    REQUIRE (L1.coeff(f,f) == -3.0);
+//    REQUIRE (L1.row(f).sum() == 0.0);
+//    REQUIRE (L1.col(f).sum() == 0.0);
+//#else
+//    //Soft assert if we have not edge_lenght_squared
+//    REQUIRE (L1.coeff(f,f) == Approx (-3.0).margin( epsilon));
+//    REQUIRE (L1.row(f).sum() == Approx (0.0).margin( epsilon));
+//    REQUIRE (L1.col(f).sum() == Approx (0.0).margin( epsilon));
+//#endif
+//  }
+  Eigen::VectorXd row_sum = L1 * Eigen::VectorXd::Constant(L1.rows(),1,1);
+  Eigen::RowVectorXd col_sum = Eigen::RowVectorXd::Constant(1,L1.rows(),1) * L1;
+  Eigen::VectorXd diag = L1.diagonal();
 #ifdef IGL_EDGE_LENGTHS_SQUARED_H
-    //Hard assert if we have edge_lenght_squared
-    REQUIRE (L1.coeff(f,f) == -3.0);
-    REQUIRE (L1.row(f).sum() == 0.0);
-    REQUIRE (L1.col(f).sum() == 0.0);
+  test_common::assert_eq( row_sum, Eigen::VectorXd::Zero(L1.rows()) );
+  test_common::assert_eq( col_sum, Eigen::RowVectorXd::Zero(L1.rows()) );
+  test_common::assert_eq(    diag, Eigen::VectorXd::Constant(L1.rows(),1,-3) );
 #else
-    //Soft assert if we have not edge_lenght_squared
-    REQUIRE (L1.coeff(f,f) == Approx (-3.0).margin( epsilon));
-    REQUIRE (L1.row(f).sum() == Approx (0.0).margin( epsilon));
-    REQUIRE (L1.col(f).sum() == Approx (0.0).margin( epsilon));
+  test_common::assert_near( row_sum, Eigen::VectorXd::Zero(L1.rows()) , epsilon);
+  test_common::assert_near( col_sum, Eigen::RowVectorXd::Zero(L1.rows()) , epsilon);
+  test_common::assert_near(    diag, Eigen::VectorXd::Constant(L1.rows(),1,-3) , epsilon);
 #endif
 
-  }
-
   //Same for huge cube.
   igl::cotmatrix(V_huge,F,L1);
   REQUIRE (L1.rows() == V.rows());