Stopping criterion reduction initializes with `numeric_limits::min()` instead of `lowest()`

Summary

Castro::post_timestep initializes max_field_val with std::numeric_limits<Real>::min(), which is the smallest positive normalized value, not the most negative value. For fields that can be negative, this biases the maximum reduction and can trigger incorrect stop decisions.

Location

• Source/driver/Castro.cpp:2133

Problem Details

Current code:

Real max_field_val = std::numeric_limits<Real>::min();

For a max reduction, the correct identity should be the lowest representable value:

std::numeric_limits<Real>::lowest()

Impact

• Incorrect stopping behavior when stopping_criterion_field can be negative.
• Possible false positives if stopping_criterion_value is negative and all field values are below threshold.

Suggested Patch

diff --git a/Source/driver/Castro.cpp b/Source/driver/Castro.cpp
--- a/Source/driver/Castro.cpp
+++ b/Source/driver/Castro.cpp
@@
-        Real max_field_val = std::numeric_limits<Real>::min();
+        Real max_field_val = std::numeric_limits<Real>::lowest();

Prepared by Codex

Start at Source/driver/Castro.cpp:2133 in Castro::post_timestep and inspect how max_field_val is used for the stopping-criterion reduction. Verify the initialization uses the correct lowest representable Real value, then check the stopping behavior for negative field values and thresholds.