olivv-cs-ComfyUI-FunPack/docs/FunPackHybridEuler2SSampler.md

FunPack Hybrid Euler 2S Sampler

This node outputs a ComfyUI SAMPLER object that can be connected directly into CustomSamplerAdvanced / SamplerCustomAdvanced.

Purpose

It is designed as a quality/speed compromise between:

• euler_ancestral: fast, reliable, one model evaluation per step
• full 2S-style samplers: higher quality, but more expensive because they need an extra evaluation every step

This sampler keeps classic Euler ancestral for most of the schedule, then applies a DPM-Solver++(2S)-style correction only on the late denoise steps where fine detail and cleanup usually matter most.

Parameters

eta: Ancestral stochasticity. 1.0 keeps normal ancestral behavior.

s_noise: Noise multiplier for ancestral noise injection.

high_quality_pct: Fraction of the late denoise steps that receive the extra 2S correction.
Example: 0.35 means only the last 35% of steps pay the extra compute cost.

correction_blend: Blend between pure Euler ancestral and the late-step 2S correction.

• 0.0 = behaves like Euler ancestral
• 1.0 = full late-step correction

Recommended starting values

• eta = 1.0
• s_noise = 1.0
• high_quality_pct = 0.30 to 0.40
• correction_blend = 1.0

For a safer first test, try:

• high_quality_pct = 0.25
• correction_blend = 0.7

Expected behavior

Compared to plain euler_ancestral, this sampler should usually:

• preserve more late-stage detail
• clean up texture and edge quality better
• cost noticeably less than a full 2S sampler

Limitation

This node improves the sampler-side quality/speed tradeoff. It does not reduce the underlying cost of CFG++ guidance itself. If the goal becomes specifically “CFG++ quality at lower guidance cost”, that likely requires a custom GUIDER, not just a custom SAMPLER.