Fixes for some line search bugs & corner cases.
- Increase precision of numeric values output in error messages to
allow for easier debugging.
- Ensure termination after Wolfe search bracketing phase if bracket
width has been shrunk to below tolerance.
- Cleaned up return value for BracketingPhase(), now false iff
optimisation should stop, true otherwise.
- Fix bug whereby we would mark a step size as satisfying the Wolfe
conditions when it did not due to numerical issues in the cost
function.
- Adding explanation of a subtlety in which a zoom could still be
acceptably invoked with bracket_low.f > bracket_high.f.
- Replacing hard check of a pre-condition of ZoomPhase() with a
conditional return if not satisfied to address issue whereby a
bracket could be incorrectly identified due to inconsistent values
& gradients returned from the cost function.
- Adding missing check for step size validity in line search minimizer.
- Adding ToDebugString() for FunctionSample.
Change-Id: Iad98e635749877f80c079ebad126bf022d82232d
diff --git a/internal/ceres/polynomial.h b/internal/ceres/polynomial.h
index 42ffdcb..80ce77e 100644
--- a/internal/ceres/polynomial.h
+++ b/internal/ceres/polynomial.h
@@ -95,6 +95,7 @@
gradient(0.0),
gradient_is_valid(false) {
}
+ string ToDebugString() const;
double x;
double value; // value = f(x)
