From 73d3a27667aff4506a20693140dc603110e48cbc Mon Sep 17 00:00:00 2001
From: Jitse Niesen <jitse@maths.leeds.ac.uk>
Date: Mon, 12 Apr 2010 18:14:32 +0100
Subject: RealSchur: Make sure zeros are really zero (cont'd); add default
 ctor, docs.

---
 test/schur_real.cpp | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

(limited to 'test/schur_real.cpp')

diff --git a/test/schur_real.cpp b/test/schur_real.cpp
index 77ef5e2dc..c1747e2f5 100644
--- a/test/schur_real.cpp
+++ b/test/schur_real.cpp
@@ -29,23 +29,19 @@ template<typename MatrixType> void verifyIsQuasiTriangular(const MatrixType& T)
 {
   const int size = T.cols();
   typedef typename MatrixType::Scalar Scalar;
-  typedef typename NumTraits<Scalar>::Real RealScalar;
-
-  // The "zeros" in the real Schur decomposition are only approximately zero
-  RealScalar norm = T.norm();
 
   // Check T is lower Hessenberg
   for(int row = 2; row < size; ++row) {
     for(int col = 0; col < row - 1; ++col) {
-      VERIFY_IS_MUCH_SMALLER_THAN(T(row,col), norm);
+      VERIFY(T(row,col) == Scalar(0));
     }
   }
 
   // Check that any non-zero on the subdiagonal is followed by a zero and is
   // part of a 2x2 diagonal block with imaginary eigenvalues.
   for(int row = 1; row < size; ++row) {
-    if (!test_ei_isMuchSmallerThan(T(row,row-1), norm)) {
-      VERIFY(row == size-1 || test_ei_isMuchSmallerThan(T(row+1,row), norm));
+    if (T(row,row-1) != Scalar(0)) {
+      VERIFY(row == size-1 || T(row+1,row) == 0);
       Scalar tr = T(row-1,row-1) + T(row,row);
       Scalar det = T(row-1,row-1) * T(row,row) - T(row-1,row) * T(row,row-1);
       VERIFY(4 * det > tr * tr);
@@ -61,9 +57,23 @@ template<typename MatrixType> void schur(int size = MatrixType::ColsAtCompileTim
     RealSchur<MatrixType> schurOfA(A);
     MatrixType U = schurOfA.matrixU();
     MatrixType T = schurOfA.matrixT();
+    std::cout << "T = \n" << T << "\n\n";
     verifyIsQuasiTriangular(T);
     VERIFY_IS_APPROX(A, U * T * U.transpose());
   }
+
+  // Test asserts when not initialized
+  RealSchur<MatrixType> rsUninitialized;
+  VERIFY_RAISES_ASSERT(rsUninitialized.matrixT());
+  VERIFY_RAISES_ASSERT(rsUninitialized.matrixU());
+  
+  // Test whether compute() and constructor returns same result
+  MatrixType A = MatrixType::Random(size, size);
+  RealSchur<MatrixType> rs1;
+  rs1.compute(A);
+  RealSchur<MatrixType> rs2(A);
+  VERIFY_IS_EQUAL(rs1.matrixT(), rs2.matrixT());
+  VERIFY_IS_EQUAL(rs1.matrixU(), rs2.matrixU());
 }
 
 void test_schur_real()
-- 
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