tree 23e6de157bca98d0930c1aa3a5d3601daf55a814
parent 0b629bd8964a81a5a900974bc158da5520d8678c
author Sameer Agarwal <sameeragarwal@google.com> 1792454137 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1792459492 -0700

Add FAQ on why CostFunctions should not return the norm of residuals

Explain why returning ||r(x)|| or ||r(x)||^2 from a CostFunction collapses the Gauss-Newton Hessian to rank 1 and causes non-differentiability or singular Jacobians at r(x) = 0.

Fixes https://github.com/ceres-solver/ceres-solver/issues/467

Change-Id: Id5437c724b414069e4788b8e363785a9976bd018