atoms_update_kernel.cu: 4-block kernel (grid=(4,1,1), block=(256,1,1)) replaces
the CPU loop that launched adaptive_atom_positions 4× per branch. Each block reads
ISV v-range slots [23..31) and spacing_raw params[52..56); computes softmax +
cumsum; writes atom_positions_buf[branch * num_atoms]. Same formula as the
existing adaptive_atom_positions kernel in experience_kernels.cu.
Deleted recompute_atom_positions and warm_start_atom_positions from GpuDqnTrainer
and their fused_training.rs delegates. step_atom_positions now calls
launch_atoms_update. training_loop.rs: recompute_atom_positions → launch_atoms_update;
warm_start_atom_positions + compute_reward_quantiles block removed.
AtomsMonitor reads ISV[V_CENTER_DIR_INDEX=23] as representative scalar;
diagnose() exposes all 8 v-range slots [23..31). state_reset_registry.rs
"follow-up task" descriptions updated for all 4 adaptive slots.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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