Autocalibration may be fixing the sign of eigenvalues incorrectly #44664

New Issue

Keir Mierle · 2015-05-11T10:28:15+02:00

Keir Mierle commented

2015-05-11 10:28:15 +02:00

Originally from: https://code.google.com/p/libmv/issues/detail?id=32#makechanges

What steps will reproduce the problem?
Reference:

  Path: libmv\src\libmv\multiview\autocalibration.cc
  Lines: 105 to 109 (see below)

// Eigen values should be possitive,
Vec temp_values = eigen_solver.eigenvalues();
if (temp_values.sum() < 0) {
  temp_values = -temp_values;
}

After execution of these lines, I am still finding negative eigen values in temp_values.

What is the expected output? What do you see instead?
If I am not wrong, this should code should replaced with the code given below to ensure non-negative eigen values:

  for( int i = 0; i < 4; i++)
  {
      if(temp_values[i] < 0){
          temp_values[i] = -temp_values[i];
      }        
  }

Originally from: https://code.google.com/p/libmv/issues/detail?id=32#makechanges **What steps will reproduce the problem?** Reference: ``` Path: libmv\src\libmv\multiview\autocalibration.cc Lines: 105 to 109 (see below) ``` ``` // Eigen values should be possitive, Vec temp_values = eigen_solver.eigenvalues(); if (temp_values.sum() < 0) { temp_values = -temp_values; } ``` After execution of these lines, I am still finding negative eigen values in temp_values. **What is the expected output? What do you see instead?** If I am not wrong, this should code should replaced with the code given below to ensure non-negative eigen values: ``` for( int i = 0; i < 4; i++) { if(temp_values[i] < 0){ temp_values[i] = -temp_values[i]; } }

Keir Mierle commented

2015-05-11 10:28:15 +02:00

Changed status to: 'Open'

Keir Mierle commented

2015-05-11 10:28:15 +02:00

Added subscriber: @Keir

Sergey Sharybin was assigned by Bastien Montagne

2015-05-26 14:39:46 +02:00

Bastien Montagne commented

2015-05-26 14:39:46 +02:00

Added subscriber: @mont29

Sergey Sharybin removed their assignment 2016-01-26 13:59:40 +01:00

Sergey Sharybin commented

2016-01-26 13:59:40 +01:00

Added subscriber: @Sergey

Sybren A. Stüvel commented

2020-02-17 12:14:56 +01:00

Added subscriber: @dr.sybren

Sybren A. Stüvel commented

2020-02-17 12:14:56 +01:00

I'm tempted to close this task, as there is no description of what error occurs or how to reproduce it. @Keir, @Sergey, is this still a change that should be applied?