Per pearl_build_rs_rerun_if_env_changed, every std::env::var() must be
paired with cargo:rerun-if-env-changed. Task #321 fixed crates/ml/build.rs
(commit e3d082968) but missed 6 sibling build.rs files. Each reads
CUDA_COMPUTE_CAP without registering the rerun directive, so cargo
sees no env-change between e.g. SM 89 (L40S) → SM 90 (H100) workflow
re-submissions and cache-hits the wrong-arch cubin from the previous
run. At runtime, the H100 fails to load the SM 89 cubin with
CUDA_ERROR_NO_BINARY_FOR_GPU on rmsnorm — exactly what killed
train-multi-seed-vlv8c (commit 0371d6a76, post-Class-B chain).
Files (all add `println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP")`
just before the env::var() read):
- crates/ml-dqn/build.rs (rmsnorm — root cause of vlv8c failure)
- crates/ml-ensemble/build.rs
- crates/ml-explainability/build.rs
- crates/ml-ppo/build.rs
- crates/ml-supervised/build.rs
- crates/ml-core/build.rs
Atomic single commit per feedback_no_partial_refactor.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three root causes of sporadic NaN during training:
1. --use_fast_math (nvcc) breaks IEEE 754 NaN semantics: fmaxf(NaN,x)
returns NaN instead of x, isnan()/isinf() compile to false.
Replaced with --ftz=true --fmad=true --prec-div=true --prec-sqrt=true
across all 4 build.rs (ml, ml-dqn, ml-ppo, ml-core).
2. Cross-stream race: replay buffer wrote batch data on the device's
original stream while the trainer read it on a forked stream.
Fixed by passing the forked stream to the DQN agent via agent_device,
so all GPU components share a single CUDA stream (zero sync overhead).
3. Rewards/dones stored as bf16 in replay buffer caused done=0xFFFF NaN.
Converted entire rewards/dones pipeline to f32: experience collector,
replay buffer storage, nstep kernel, loss/grad kernels.
Also:
- Removed fast_isnan/fast_isinf/fast_isfinite wrappers — standard
isnan/isinf/isfinite work correctly without --use_fast_math
- Updated dqn-smoketest.toml: lr=1e-4, epsilon=1e-8 (f32 Adam values)
- Removed debug printfs from gather kernels
- Added curiosity_weight to training profile system
- Cleaned up smoke_params() inline overrides
11/11 smoke tests pass, 5/5 stress runs of 50-epoch test pass,
359/359 ml-dqn + 895/895 ml unit tests pass.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>