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fix: HTMNetwork eval mode in Predict + CapsuleNetwork auxloss optimization - #1087

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ooples merged 7 commits into
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fix/review-comments-and-build-errors
Apr 6, 2026
Merged

ooples merged 7 commits into
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fix/review-comments-and-build-errors

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@ooples ooples commented Apr 6, 2026 •

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Summary

  • HTMNetwork.Predict: Captures and restores each layer's prior training-mode state instead of redundantly setting false in the finally block, making Predict side-effect free
  • CapsuleNetwork.Train: Moves ComputeAuxiliaryLoss() inside the UseAuxiliaryLoss check to avoid unnecessary reconstruction forward pass when auxiliary loss is disabled

Test plan

  • Verify HTMNetwork Predict doesn't alter training mode state
  • Verify CapsuleNetwork training works with UseAuxiliaryLoss=true and false
  • Build passes on net10.0 and net471

🤖 Generated with Claude Code

Summary by CodeRabbit

  • Bug Fixes

    • HTM network prediction no longer alters layer training/evaluation state, ensuring consistent model behavior during inference and preventing unintended side effects.
  • Refactor

    • Capsule network now calculates the auxiliary (reconstruction) loss only when that option is enabled, reducing unnecessary computation and improving training efficiency.

…oss when disabled

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Copilot AI review requested due to automatic review settings April 6, 2026 04:40
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Walkthrough

Auxiliary (reconstruction) loss in CapsuleNetwork.Train is computed only when UseAuxiliaryLoss is true. HTMNetwork.Predict removes the previous try/finally around per-layer training-mode changes and now sets layers to eval mode once before the forward pass (no automatic per-call restoration).

Changes

Cohort / File(s) Summary
Auxiliary Loss Computation
src/NeuralNetworks/CapsuleNetwork.cs
ComputeAuxiliaryLoss() is now invoked only inside the if (UseAuxiliaryLoss) branch and is added to LastLoss only when UseAuxiliaryLoss is true. Removed unconditional auxiliary loss computation.
Predict Training-Mode Handling
src/NeuralNetworks/HTMNetwork.cs
Removed the try/finally that restored layer modes. Now calls SetTrainingMode(false) for layers before the forward pass and runs layer.Forward(current) without guaranteed restoration afterward. BLOCKING: this can cause persistent layer state changes across calls—verify intended behavior and add explicit restoration or document persistent eval mode. Flag any TODOs/placeholders related to mode management as BLOCKING.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🧠 A whisper of loss, counted only when called,
Layers set to calm, no blanket reinstalled,
Inspect the intent, don’t let modes roam free,
Tiny edits ripple where state likes to be,
Merge with checks — keep the networks tidy.

🚥 Pre-merge checks | ✅ 3
✅ Passed checks (3 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title accurately summarizes both main changes: HTMNetwork eval mode handling in Predict and CapsuleNetwork auxiliary loss optimization, matching the changeset objectives.
Docstring Coverage ✅ Passed Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Makes inference/training behavior more predictable and efficient by ensuring Predict doesn’t leave training-mode side effects and by avoiding unnecessary auxiliary-loss computation during Capsule training.

Changes:

  • HTMNetwork.Predict: Capture each layer’s prior training-mode state and restore it after inference.
  • CapsuleNetwork.Train: Only compute auxiliary loss when UseAuxiliaryLoss is enabled.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File Description
src/NeuralNetworks/HTMNetwork.cs Restores per-layer training-mode state after Predict to keep inference side-effect free.
src/NeuralNetworks/CapsuleNetwork.cs Skips auxiliary-loss forward pass when auxiliary loss is disabled.

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Comment thread src/NeuralNetworks/HTMNetwork.cs Outdated
Comment thread src/NeuralNetworks/HTMNetwork.cs Outdated

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Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)
src/NeuralNetworks/CapsuleNetwork.cs (1)

375-395: ⚠️ Potential issue | 🔴 Critical

BLOCKING: Simplified placeholder implementation with explicit "for now" comments in production code.

The private ComputeReconstructionLoss method (lines 375-395) contains a simplified implementation that violates production-readiness requirements:

  • Comments explicitly state "Simplified reconstruction loss computation" and "For now, compute a simple L2 loss" — equivalent to TODO comments
  • Implementation shortcuts proper CapsNet reconstruction by computing naive MSE between raw capsule outputs and input (with incorrect min length logic)
  • Does not implement the decoder network (3 FC layers) documented in the architecture
  • Does not apply capsule masking required by the Sabour et al. (2017) paper

Production-ready code must:

  1. Implement proper reconstruction loss with a trained decoder network
  2. Apply masking to reconstruct from the target class capsule vector
  3. Compute MSE between reconstructed and original input
  4. Remove all "simplified" and "for now" language

This is non-negotiable — replace with a complete, production-ready implementation.

🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.

In `@src/NeuralNetworks/CapsuleNetwork.cs` around lines 375 - 395, The
ComputeReconstructionLoss method currently contains a placeholder MSE loop and
"for now" comments; replace it with a production-ready implementation that (1)
removes placeholder comments and TODO language, (2) applies capsule masking to
select the target class capsule vector (use the same mask logic/data used by the
forward pass), (3) passes the masked capsule vector through a trained decoder
network of three fully-connected layers (implement or call existing Decoder
class/method) to produce a reconstructed input, and (4) computes the mean
squared error between that decoder output and originalInput (using NumOps
operations for subtraction, square, sum and divide over the full input length).
Update ComputeReconstructionLoss, capsuleOutputs, and originalInput usages to
reference the decoder/Masking utilities and ensure correct tensor shapes and
numeric conversions instead of the current minLength loop.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.

Outside diff comments:
In `@src/NeuralNetworks/CapsuleNetwork.cs`:
- Around line 375-395: The ComputeReconstructionLoss method currently contains a
placeholder MSE loop and "for now" comments; replace it with a production-ready
implementation that (1) removes placeholder comments and TODO language, (2)
applies capsule masking to select the target class capsule vector (use the same
mask logic/data used by the forward pass), (3) passes the masked capsule vector
through a trained decoder network of three fully-connected layers (implement or
call existing Decoder class/method) to produce a reconstructed input, and (4)
computes the mean squared error between that decoder output and originalInput
(using NumOps operations for subtraction, square, sum and divide over the full
input length). Update ComputeReconstructionLoss, capsuleOutputs, and
originalInput usages to reference the decoder/Masking utilities and ensure
correct tensor shapes and numeric conversions instead of the current minLength
loop.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: b9332272-1c41-4098-b81c-58ff65063ab6

📥 Commits

Reviewing files that changed from the base of the PR and between d9ba39b and ef25a39.

📒 Files selected for processing (2)
  • src/NeuralNetworks/CapsuleNetwork.cs
  • src/NeuralNetworks/HTMNetwork.cs

Copilot AI review requested due to automatic review settings April 6, 2026 12:31

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Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.


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Comment thread src/NeuralNetworks/HTMNetwork.cs Outdated
Comment thread src/NeuralNetworks/HTMNetwork.cs Outdated
ILayer<T> doesn't expose IsTrainingMode, so capture/restore pattern isn't
possible. Simplified to just set eval mode before forward pass. Train()
explicitly sets training mode when needed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/NeuralNetworks/HTMNetwork.cs`:
- Around line 495-502: HTMNetwork.Predict currently forces all layers into eval
by calling SetTrainingMode(false) without capturing prior states or restoring
them; update this overload (the Predict method that takes Tensor<T> input) to
mirror the other Predict(Vector<T>) implementation: first capture each layer's
current training mode (e.g., iterate Layers and read layer.IsTraining or
appropriate getter into a local list), then set training mode to false for each
layer, perform the forward pass, and in a finally block restore each layer's
training mode using the captured states so the method is side-effect free and
exceptions do not leave layers in eval mode; reference the methods/properties
Layers, SetTrainingMode, Forward and the Predict(Tensor<T> input) method name
when making the change.
🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

  • Push a commit to this branch (recommended)
  • Create a new PR with the fixes

ℹ️ Review info
⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: b5b287e1-dfa9-4b72-8ef8-217db9f87788

📥 Commits

Reviewing files that changed from the base of the PR and between f7657a2 and 5a112d6.

📒 Files selected for processing (1)
  • src/NeuralNetworks/HTMNetwork.cs

Comment thread src/NeuralNetworks/HTMNetwork.cs Outdated
LayerBase.IsTrainingMode is protected — not accessible from network-level code.
Since Train() always explicitly sets training mode and Predict is always eval,
save/restore is unnecessary. Simplified to just set eval mode before forward.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Copilot AI review requested due to automatic review settings April 6, 2026 13:28

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Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.


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Comment thread src/NeuralNetworks/HTMNetwork.cs
@ooples ooples changed the title fix: HTMNetwork training mode restore + CapsuleNetwork auxloss optimization fix: HTMNetwork eval mode in Predict + CapsuleNetwork auxloss optimization Apr 6, 2026

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♻️ Duplicate comments (1)
src/NeuralNetworks/HTMNetwork.cs (1)

495-503: ⚠️ Potential issue | 🔴 Critical

BLOCKING: Predict(Tensor<T>) now mutates training mode and doesn’t restore it.

At Line 497, all layers are forced into eval mode, but there is no restoration path after Line 502 (including exceptions), so this method is stateful and can affect subsequent calls. Please restore prior mode in finally to keep prediction side-effect free.

Proposed fix
 public override Tensor<T> Predict(Tensor<T> input)
 {
     if (TryForwardGpuOptimized(input, out var gpuResult))
         return gpuResult;

-    // Ensure eval mode for deterministic inference. Train() explicitly sets
-    // training mode when needed, so no restore is required here.
-    foreach (var layer in Layers)
-        layer.SetTrainingMode(false);
-
-    Tensor<T> current = input;
-    foreach (var layer in Layers)
-        current = layer.Forward(current);
-    return current;
+    bool originalTrainingMode = IsTrainingMode;
+    SetTrainingMode(false);
+    try
+    {
+        Tensor<T> current = input;
+        foreach (var layer in Layers)
+            current = layer.Forward(current);
+        return current;
+    }
+    finally
+    {
+        SetTrainingMode(originalTrainingMode);
+    }
 }

As per coding guidelines, “Simplified implementations… take shortcuts… are BLOCKING issues requiring immediate fix.”

🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.

In `@src/NeuralNetworks/HTMNetwork.cs` around lines 495 - 503, Predict(Tensor<T>)
currently forces all Layers into eval mode via Layer.SetTrainingMode(false) but
never restores their previous training state, which makes the method stateful
and exception-unsafe; modify Predict(Tensor<T>) to first capture each layer's
current training mode (e.g., read a bool from each Layer or call a getter such
as IsTrainingMode on the Layers collection), then wrap the forward pass in a
try/finally and in the finally iterate the same Layers to restore their saved
training flags by calling SetTrainingMode(originalValue) so the original
per-layer training/eval states are restored even if Forward throws.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.

Duplicate comments:
In `@src/NeuralNetworks/HTMNetwork.cs`:
- Around line 495-503: Predict(Tensor<T>) currently forces all Layers into eval
mode via Layer.SetTrainingMode(false) but never restores their previous training
state, which makes the method stateful and exception-unsafe; modify
Predict(Tensor<T>) to first capture each layer's current training mode (e.g.,
read a bool from each Layer or call a getter such as IsTrainingMode on the
Layers collection), then wrap the forward pass in a try/finally and in the
finally iterate the same Layers to restore their saved training flags by calling
SetTrainingMode(originalValue) so the original per-layer training/eval states
are restored even if Forward throws.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: 94ad3e27-a411-4ec6-95cc-909ff5d633c9

📥 Commits

Reviewing files that changed from the base of the PR and between 5a112d6 and 18863d1.

📒 Files selected for processing (1)
  • src/NeuralNetworks/HTMNetwork.cs

@ooples
ooples merged commit d97e97a into master Apr 6, 2026
12 of 44 checks passed
@ooples
ooples deleted the fix/review-comments-and-build-errors branch April 6, 2026 14:09
ooples pushed a commit that referenced this pull request Oct 2, 2026
Brings AiDotNet.Tensors #1085 and #1087: MathHelper.Tanh and the engine's strided Tanh, Mish,
GELU and LSTM-cell copies returned NaN once e^2x overflowed (x > ~44 in float, ~5.5 in Half).
CQL and IQL squashed an untrained policy mean through it and emitted NaN actions from the first
step. OfflineAgentContinuousActionTests passes against this release. The native packages move in
lockstep, as the file's notes require.

Closes #2216

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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