From b78fd2f1f098712a49e943c3dac91e63d75a69c8 Mon Sep 17 00:00:00 2001
From: jgrusewski <jgrusewski@localhost>
Date: Mon, 20 Apr 2026 22:32:08 +0200
Subject: [PATCH] =?UTF-8?q?cleanup(fflag):=20remove=20enable=5Fq=5Fvalue?=
 =?UTF-8?q?=5Fclipping=20=E2=80=94=20always=20clip=20=E2=80=94=20[FFLAG-00?=
 =?UTF-8?q?3]?=
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DQNConfig.enable_q_value_clipping was true at all 4 construction sites;
the else branch returned the pre-clamp tensor unchanged (dead identity
path). Q-value clipping is a BUG #37 fix — clipping happens after
forward pass so gradients still flow, and prevents Q-value explosions
from poisoning action selection. Per feedback_no_feature_flags.md, the
flag is gone — clipping is now unconditional. Kept q_value_clip_min /
q_value_clip_max since they're still passed to clamp().
---
 crates/ml-dqn/src/dqn.rs | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/crates/ml-dqn/src/dqn.rs b/crates/ml-dqn/src/dqn.rs
index a98249f24..24014a3b3 100644
--- a/crates/ml-dqn/src/dqn.rs
+++ b/crates/ml-dqn/src/dqn.rs
@@ -111,10 +111,7 @@ pub struct DQNConfig {
     /// Initial standard deviation for noisy layers
     pub noisy_sigma_init: f64,
 
-    // BUG #37 FIX: Q-value clipping configuration (prevents step-level explosions)
-    /// Whether to enable Q-value clipping in forward pass
-    /// Default: true (prevents explosions without breaking gradients)
-    pub enable_q_value_clipping: bool,
+    // BUG #37 FIX: Q-value clipping is unconditional in forward pass (prevents step-level explosions)
     /// Minimum Q-value bound (clipped during forward pass)
     /// Default: -500.0 (based on portfolio normalization baseline ±375 × 1.33 safety margin)
     pub q_value_clip_min: f32,
@@ -267,7 +264,6 @@ impl Default for DQNConfig {
             v_min: -(10.0_f32 / (1.0 - 0.95) * 1.2).clamp(20.0, 300.0),
             v_max: (10.0_f32 / (1.0 - 0.95) * 1.2).clamp(20.0, 300.0),
             noisy_sigma_init: 0.5,
-            enable_q_value_clipping: true,
             q_value_clip_min: -200.0,  // Reward v6: tighter than old -500 but covers v_range + safety margin
             q_value_clip_max: 200.0,
             gradient_collapse_multiplier: 2.0,
@@ -579,7 +575,6 @@ impl DQNConfig {
             noisy_sigma_init: 0.5,
 
             // BUG #37 FIX: Q-value clipping (prevents step-level explosions)
-            enable_q_value_clipping: true,
             q_value_clip_min: -1000.0,  // Wider bounds for aggressive exploration
             q_value_clip_max: 1000.0,
 
@@ -644,7 +639,6 @@ impl DQNConfig {
             noisy_sigma_init: 0.5,
 
             // BUG #37 FIX: Q-value clipping (prevents step-level explosions)
-            enable_q_value_clipping: true,
             q_value_clip_min: -200.0,  // Reward v6: tighter than old -500 but covers v_range + safety margin
             q_value_clip_max: 200.0,
 
@@ -719,7 +713,6 @@ impl DQNConfig {
             noisy_sigma_init: 0.5,
 
             // BUG #37 FIX: Q-value clipping (prevents step-level explosions)
-            enable_q_value_clipping: true,
             q_value_clip_min: -200.0,  // Reward v6: tighter than old -500 but covers v_range + safety margin
             q_value_clip_max: 200.0,
 
@@ -1217,7 +1210,7 @@ impl DQN {
         //   1. Clipping happens AFTER forward pass (inference)
         //   2. Gradients flow through during backward (no gradient death)
         //   3. Prevents extreme Q-values from propagating through action selection
-        let q_values = if self.config.enable_q_value_clipping {
+        let q_values = {
             let clamped = q_values.clamp(
                 self.config.q_value_clip_min,
                 self.config.q_value_clip_max,
@@ -1260,8 +1253,6 @@ impl DQN {
             }
 
             clamped
-        } else {
-            q_values
         };
 
         // Cast output back to F32 for API compatibility (callers expect f32 tensors)