No known conversion from 'unique_ptr<LinearSolverEigen<...>>' to 'unique_ptr<LinearSolverType>'

[zhangyx1998]

I am trying to build ORB_SLAM3 locally. As part of my attempt to fix compile errors, I replaced the project's outdated copy of g2o with the latest version.

I am not sure if change of version caused the error shown in the title. I tried to trace down the source code but could not find a solution on myself. Although this may not be an issue of g2o itself, I would really appreciate some help to fix it.

To provide more context, my work-in-progress fork of ORB_SLAM3 can be found here. The problematic code is located here.

The original code from existing ORB_SLAM3 project looks like this:

  g2o::SparseOptimizer optimizer;
  g2o::BlockSolver_6_3::LinearSolverType * linearSolver;
  linearSolver = new g2o::LinearSolverEigen<g2o::BlockSolver_6_3::PoseMatrixType>();
  g2o::BlockSolver_6_3 * solver_ptr = new g2o::BlockSolver_6_3(linearSolver);
  g2o::OptimizationAlgorithmLevenberg* solver = new g2o::OptimizationAlgorithmLevenberg(solver_ptr);

It failed to compile because new g2o::BlockSolver expects unique_ptr in the latest version.

My modified version looks like this:

I used std::make_unique on linearSolver to fix the issue above.

  g2o::SparseOptimizer optimizer;
  auto linearSolver = std::make_unique<g2o::LinearSolverEigen<g2o::BlockSolver_6_3::PoseMatrixType>>();
  auto solver_ptr = new g2o::BlockSolver_6_3(linearSolver);
  auto solver = new g2o::OptimizationAlgorithmLevenberg(solver_ptr);

This version produces the error shown in the title.

Attached is the raw error output from my compiler (I tried both GCC and Clang, both produced the same error): gcc_compile_log.txt

GCC Version: gcc (Ubuntu 13.2.0-23ubuntu4) 13.2.0

Clang Version: Ubuntu clang version 18.1.3 (1ubuntu1)

Again, many thanks!

[zhangyx1998]

Seems like std::move() solves this problem.