ComfyUI Deterministic Nodes

Batch-invariant inference nodes for guaranteed reproducibility in ComfyUI.

The Problem

temperature=0 is NOT enough for determinism.

The real culprit is batch-size variance. Same prompt, same seed, different batch sizes = different outputs.

The Solution

These nodes enforce batch_size=1 processing with fixed RNG states, guaranteeing:

Same seed + Same prompt = Identical output (ALWAYS)

Based on ThinkingMachines batch-invariant-ops research.

Nodes (all in JI/Reproducible category)

Display Name	What It Does
Locked Sampler ⟳	Same seed = same output, every time
Output Matcher	Verify your outputs match exactly
Expert Selector	Pick the right AI model for your task
Multi-Pass Refiner	Refine in 3 stages (coarse → detail)
Memory Recall	Retrieve context from 4-tier memory

Locked Sampler ⟳

Guarantees identical outputs with the same seed:

• Forces batch_size=1 internally (the secret sauce)
• Resets RNG for each item
• Disables GPU auto-tuning variance
• Outputs proof checksum

Output Matcher

Verify reproducibility with configurable tolerance:

• exact: Byte-for-byte match
• epsilon_1e-6: Allow tiny floating-point variance
• epsilon_1e-4: Allow small floating-point variance
• structural: Shape and dtype match only

Expert Selector

Pick the right AI model automatically:

• Hash-based selection (consistent every time)
• Supports up to 4 expert models
• Same input = same expert (ALWAYS)

Multi-Pass Refiner

Refine in stages (like render passes):

• Stage 1: Coarse pass
• Stage 2: Refinement
• Stage 3: Detail
• Different seed per stage for diversity within determinism

Memory Recall

Retrieve context from 4-tier memory:

• Hot: GPU VRAM (active)
• Warm: System RAM (recent)
• Cold: NVMe (historical)
• Archive: Network (full)

Installation

Copy to ComfyUI custom_nodes:

ComfyUI/custom_nodes/ComfyUI-DeterministicNodes/

Restart ComfyUI.

Usage

Reproducibility Workflow

[Model] --> [Locked Sampler] --> [Output Matcher] --> [Output]
                   |                      |
                   +-- seed=42 ----------+
                   |                      |
                   +-- checksum ---------+-- verify on next run

Multi-Model Workflow

[Prompt] --> [Expert Selector] --> [Selected Model] --> [Locked Sampler]
                  |
                  +-- expert_0: General
                  +-- expert_1: Code
                  +-- expert_2: Domain
                  +-- expert_3: Math

Context-Aware Workflow

[Query] --> [Memory Recall] --> [Prompt with Context] --> [Model]
                  |
                  +-- hot_only: Fast, GPU cache
                  +-- hot_warm: Recent context
                  +-- all_tiers: Full history

Technical Details

Why Batch-Invariance Matters

Batch=1:  "The answer is 42"
Batch=4:  "The answer is 41"  <-- DIFFERENT!
Batch=8:  "The answer is 43"  <-- DIFFERENT!

GPU parallel operations have floating-point accumulation order variance. Different batch sizes = different accumulation order = different results.

The Fix

1. Process items one at a time (batch_size=1)
2. Reset RNG before each item (seed + item_index)
3. Disable cuDNN auto-tuning (cudnn.benchmark=False)
4. Use deterministic algorithms (torch.use_deterministic_algorithms(True))

Framework Integration

These nodes integrate with:

• ECHO 2.0: 4-tier context memory → Memory Recall
• CSQMF-R1: Expert routing → Expert Selector
• Nemotron: Cascade refinement → Multi-Pass Refiner
• ThinkingMachines: Batch-invariant inference → Locked Sampler

License

Dual-licensed under AGPL-3.0 and Commercial licenses.

Use Case	License	Requirements
Open source projects	AGPL-3.0	Release derivatives under AGPL-3.0
Personal/educational	AGPL-3.0	Attribution required
SaaS/proprietary	Commercial	Contact for license

See COMMERCIAL_LICENSE.md for commercial terms.

Why dual-license? Batch-invariant inference and deterministic routing are novel contributions. AGPL ensures community improvements flow back while commercial licensing enables proprietary use.

Author

Joseph Ibrahim - VFX Lighting TD

• Portfolio: josephibrahim.com
• Commercial inquiries: joseph@josephibrahim.com

---

Determinism is not optional. It's a requirement.