From: Martin Kronbichler <martin.kronbichler@uni-a.de>
Date: Mon, 13 Mar 2023 18:13:01 +0000 (+0100)
Subject: Add matrix with singular eigenvector matrix
X-Git-Tag: v9.5.0-rc1~474^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F14865%2Fhead;p=dealii.git

Add matrix with singular eigenvector matrix
---

diff --git a/tests/lapack/full_matrix_38.cc b/tests/lapack/full_matrix_38.cc
index f84e30fb55..81ead78bbb 100644
--- a/tests/lapack/full_matrix_38.cc
+++ b/tests/lapack/full_matrix_38.cc
@@ -38,12 +38,20 @@ const double mat1[2][2] = {{4., -1.}, {-1., 4.}};
  */
 const double mat2[2][2] = {{1., -1.}, {1., 1.}};
 
+/*
+ * Eigenvalues and -vectors of this system are
+ * lambda = 1     v = (1, 0, 0)
+ * lambda = 1     v = (0, 1, 0)
+ * lambda = 1     v = (-1, 0, 0)
+ */
+const double mat3[3][3] = {{1., 0, 2.}, {0., 1., 0.}, {0., 0., 1.}};
+
 
 void
-check_matrix(const double *matrix_pointer)
+check_matrix(const double *matrix_pointer, const unsigned int size)
 {
-  FullMatrix<double>       A(2, 2, matrix_pointer);
-  LAPACKFullMatrix<double> LA(2, 2);
+  FullMatrix<double>       A(size, size, matrix_pointer);
+  LAPACKFullMatrix<double> LA(size, size);
   LA = A;
 
   deallog << "Checking matrix " << std::endl;
@@ -58,9 +66,9 @@ check_matrix(const double *matrix_pointer)
     }
   deallog << std::endl;
   deallog << "Right eigenvectors" << std::endl;
-  LA.get_right_eigenvectors().print_formatted(deallog.get_file_stream());
+  LA.get_right_eigenvectors().print(deallog.get_file_stream());
   deallog << "Left eigenvectors" << std::endl;
-  LA.get_left_eigenvectors().print_formatted(deallog.get_file_stream());
+  LA.get_left_eigenvectors().print(deallog.get_file_stream());
   deallog << std::endl;
 }
 
@@ -72,8 +80,11 @@ main()
   initlog();
 
   // Test symmetric system
-  check_matrix(&mat1[0][0]);
+  check_matrix(&mat1[0][0], 2);
 
   // Test non-symmetric system with complex eigenvalues/eigenvectors
-  check_matrix(&mat2[0][0]);
+  check_matrix(&mat2[0][0], 2);
+
+  // Test case of one eigenvalue with two associated eigenvectors
+  check_matrix(&mat3[0][0], 3);
 }
diff --git a/tests/lapack/full_matrix_38.output b/tests/lapack/full_matrix_38.output
index 28e5a4ca21..86c641da78 100644
--- a/tests/lapack/full_matrix_38.output
+++ b/tests/lapack/full_matrix_38.output
@@ -4,20 +4,34 @@ DEAL::Checking matrix
 -1.000e+00 4.000e+00  
 DEAL::Eigenvalues: (5.00000,0.00000) (3.00000,0.00000) 
 DEAL::Right eigenvectors
-(7.071e-01,0.000e+00) (7.071e-01,0.000e+00) 
-(-7.071e-01,0.000e+00) (7.071e-01,0.000e+00) 
+(0.71,0.0)(0.71,0.0)
+(-0.71,0.0)(0.71,0.0)
 DEAL::Left eigenvectors
-(7.071e-01,0.000e+00) (7.071e-01,0.000e+00) 
-(-7.071e-01,0.000e+00) (7.071e-01,0.000e+00) 
+(0.71,0.0)(0.71,0.0)
+(-0.71,0.0)(0.71,0.0)
 DEAL::
 DEAL::Checking matrix 
 1.000e+00  -1.000e+00 
 1.000e+00  1.000e+00  
 DEAL::Eigenvalues: (1.00000,1.00000) (1.00000,-1.00000) 
 DEAL::Right eigenvectors
-(7.071e-01,0.000e+00) (7.071e-01,0.000e+00) 
-(0.000e+00,-7.071e-01) (0.000e+00,7.071e-01) 
+(0.71,0.0)(0.71,0.0)
+(0.0,-0.71)(0.0,0.71)
 DEAL::Left eigenvectors
-(-7.071e-01,0.000e+00) (-7.071e-01,0.000e+00) 
-(0.000e+00,7.071e-01) (0.000e+00,-7.071e-01) 
+(-0.71,0.0)(-0.71,0.0)
+(0.0,0.71)(0.0,-0.71)
+DEAL::
+DEAL::Checking matrix 
+1.000e+00             2.000e+00  
+           1.000e+00             
+                      1.000e+00  
+DEAL::Eigenvalues: (1.00000,0.00000) (1.00000,0.00000) (1.00000,0.00000) 
+DEAL::Right eigenvectors
+(1.0,0.0)(0.0,0.0)(-1.0,0.0)
+(0.0,0.0)(1.0,0.0)(0.0,0.0)
+(0.0,0.0)(0.0,0.0)(1.1e-16,0.0)
+DEAL::Left eigenvectors
+(1.1e-16,0.0)(0.0,0.0)(0.0,0.0)
+(0.0,0.0)(1.0,0.0)(0.0,0.0)
+(-1.0,0.0)(0.0,0.0)(1.0,0.0)
 DEAL::