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silveroxides-ComfyUI-ModelU…/nodes/lora_resize.py
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Python

"""
LoRA Resize - Resize existing LoRAs to different ranks.
Based on kohya_ss resize_lora.py. Merges LoRA weights and re-extracts via SVD.
Supports fixed rank and dynamic methods (sv_ratio, sv_fro, sv_cumulative).
"""
import os
import re
import torch
import torch.linalg as linalg
import folder_paths
import comfy.utils
from tqdm import tqdm
from comfy_api.latest import io
from safetensors.torch import save_file
from typing import Optional, Dict, Tuple, List
from .device_utils import estimate_model_size, prepare_for_large_operation, cleanup_after_operation
from unifiedefficientloader import MemoryEfficientSafeOpen, transfer_to_gpu_pinned
# Reuse rank functions from extraction module
from .lora_extract_svd import (
_index_sv_ratio,
_index_sv_cumulative,
_index_sv_fro,
_svd_extract_linear,
_svd_extract_conv,
_compile_patterns,
_matches_any_pattern,
_format_lora_key,
)
MIN_SV = 1e-6
# =============================================================================
# LoRA Format Detection - Support various LoRA sources
# =============================================================================
def detect_lora_format(keys: List[str]) -> Dict:
"""
Detect LoRA format and key patterns from various sources.
Supports:
- Kohya/A1111: lora_unet_*, lora_te_*
- Diffusers: *.lora_A.weight, *.lora_B.weight
- PEFT: base_model.model.*.lora_A/B
- ComfyUI native: *.lora_down.weight, *.lora_up.weight
- HuggingFace: *.lora.down.weight, *.lora.up.weight (dots instead of underscores)
- Full diff: *.diff, *.diff_b (full weight differences, not low-rank)
- Flux/SDXL: Various transformer key patterns
Returns:
Dict with format info and key patterns
"""
format_info = {
"format": "unknown",
"down_suffix": ".lora_down.weight",
"up_suffix": ".lora_up.weight",
"alpha_suffix": ".alpha",
"has_alpha": False,
"key_count": 0,
"is_full_diff": False, # New flag for full diff format
}
# Check for alpha keys
alpha_keys = [k for k in keys if '.alpha' in k or k.endswith('alpha')]
format_info["has_alpha"] = len(alpha_keys) > 0
# Detect format by key patterns
sample_keys = keys[:50] # Check more keys for full_diff detection
# Full diff format: *.diff (NOT .lora_down, just straight weight diff)
if any(k.endswith('.diff') for k in sample_keys):
format_info["format"] = "full_diff"
format_info["down_suffix"] = ".diff" # Used for pairing, but no up
format_info["up_suffix"] = None # No up weight in full diff
format_info["alpha_suffix"] = None
format_info["is_full_diff"] = True
# Kohya/A1111 format: lora_unet_down_blocks_0_*.lora_down.weight
elif any('lora_unet_' in k or 'lora_te' in k for k in sample_keys):
format_info["format"] = "kohya"
format_info["down_suffix"] = ".lora_down.weight"
format_info["up_suffix"] = ".lora_up.weight"
# Diffusers format: transformer.*.lora_A.weight
elif any('.lora_A.weight' in k for k in sample_keys):
format_info["format"] = "diffusers"
format_info["down_suffix"] = ".lora_A.weight"
format_info["up_suffix"] = ".lora_B.weight"
format_info["alpha_suffix"] = ".alpha"
# PEFT format: base_model.model.*.lora_A.default.weight
elif any('base_model.model.' in k and 'lora_' in k for k in sample_keys):
format_info["format"] = "peft"
# Handle nested structure
format_info["down_suffix"] = ".lora_A.default.weight"
format_info["up_suffix"] = ".lora_B.default.weight"
# HuggingFace format: transformer.*.lora.down.weight (dots instead of underscores)
elif any('.lora.down.weight' in k for k in sample_keys):
format_info["format"] = "huggingface"
format_info["down_suffix"] = ".lora.down.weight"
format_info["up_suffix"] = ".lora.up.weight"
format_info["alpha_suffix"] = ".alpha"
# ComfyUI native / standard
elif any('.lora_down.weight' in k for k in sample_keys):
format_info["format"] = "comfy"
format_info["down_suffix"] = ".lora_down.weight"
format_info["up_suffix"] = ".lora_up.weight"
# Count LoRA layers
down_keys = [k for k in keys if format_info["down_suffix"] in k]
format_info["key_count"] = len(down_keys)
return format_info
def extract_lora_pairs(keys: List[str], format_info: Dict) -> Dict[str, Dict[str, str]]:
"""
Group LoRA keys into down/up/alpha pairs.
For full_diff format, groups .diff and .diff_b keys.
Returns:
Dict[block_name, {"down": key, "up": key, "alpha": key}]
For full_diff: {"diff": key, "diff_b": key}
"""
down_suffix = format_info["down_suffix"]
up_suffix = format_info["up_suffix"]
alpha_suffix = format_info["alpha_suffix"]
is_full_diff = format_info.get("is_full_diff", False)
pairs = {}
if is_full_diff:
# Full diff format: group .diff and .diff_b
for key in keys:
if key.endswith('.diff'):
block_name = key[:-5] # Remove .diff
if block_name not in pairs:
pairs[block_name] = {}
pairs[block_name]["diff"] = key
elif key.endswith('.diff_b'):
block_name = key[:-7] # Remove .diff_b
if block_name not in pairs:
pairs[block_name] = {}
pairs[block_name]["diff_b"] = key
else:
# Standard LoRA format
for key in keys:
if down_suffix and down_suffix in key:
block_name = key.replace(down_suffix, "")
if block_name not in pairs:
pairs[block_name] = {}
pairs[block_name]["down"] = key
elif up_suffix and up_suffix in key:
block_name = key.replace(up_suffix, "")
if block_name not in pairs:
pairs[block_name] = {}
pairs[block_name]["up"] = key
elif alpha_suffix and (alpha_suffix in key or key.endswith('.alpha')):
# Handle various alpha key formats
block_name = key.replace(alpha_suffix, "").replace(".alpha", "")
if block_name not in pairs:
pairs[block_name] = {}
pairs[block_name]["alpha"] = key
return pairs
def detect_lora_rank(handler: MemoryEfficientSafeOpen, pairs: Dict) -> Tuple[int, float]:
"""
Detect the rank and alpha of an existing LoRA.
Returns:
(network_dim, network_alpha)
"""
network_dim = None
network_alpha = None
for block_name, block_keys in pairs.items():
if "down" not in block_keys:
continue
# Get dim from down weight shape
if network_dim is None:
down_key = block_keys["down"]
shape = handler.get_shape(down_key)
# Linear: [rank, in_features] or Conv: [rank, in_ch, k, k]
network_dim = shape[0]
# Get alpha if present
if network_alpha is None and "alpha" in block_keys:
alpha_tensor = handler.get_tensor(block_keys["alpha"])
network_alpha = float(alpha_tensor.item())
if network_dim is not None and network_alpha is not None:
break
# Default alpha to dim if not found
if network_alpha is None:
network_alpha = float(network_dim) if network_dim else 1.0
if network_dim is None:
network_dim = 1
return network_dim, network_alpha
# =============================================================================
# Merge Functions
# =============================================================================
def _merge_linear(lora_down: torch.Tensor, lora_up: torch.Tensor, device: str) -> torch.Tensor:
"""Merge linear LoRA weights: lora_up @ lora_down."""
lora_down = lora_down.to(device=device, dtype=torch.float32)
lora_up = lora_up.to(device=device, dtype=torch.float32)
return lora_up @ lora_down
def _merge_conv(lora_down: torch.Tensor, lora_up: torch.Tensor, device: str) -> torch.Tensor:
"""Merge conv LoRA weights."""
in_rank, in_size, kernel_size, k_ = lora_down.shape
out_size, out_rank, _, _ = lora_up.shape
assert in_rank == out_rank, f"rank mismatch: {in_rank} vs {out_rank}"
lora_down = lora_down.to(device=device, dtype=torch.float32)
lora_up = lora_up.to(device=device, dtype=torch.float32)
merged = lora_up.reshape(out_size, -1) @ lora_down.reshape(in_rank, -1)
return merged.reshape(out_size, in_size, kernel_size, kernel_size)
# =============================================================================
# Extract Functions (after merge)
# =============================================================================
def _extract_linear(
weight: torch.Tensor,
max_rank: int,
dynamic_method: Optional[str],
dynamic_param: Optional[float],
scale: float,
niter: int = 2,
) -> Dict:
"""Extract LoRA from merged linear weight."""
out_size, in_size = weight.shape
if dynamic_method is None:
# Fixed rank - use svd_lowrank for 10x speedup
rank = min(max_rank, min(out_size, in_size) - 1)
U, S, Vh = torch.svd_lowrank(weight, q=rank, niter=niter)
Vh = Vh.T # svd_lowrank returns V, not Vh
new_rank = rank
new_alpha = float(scale * new_rank)
stats = {"sum_retained": 1.0, "fro_retained": 1.0} # Not computed for lowrank
else:
# Dynamic methods need full SVD to compute rank from all singular values
U, S, Vh = linalg.svd(weight, full_matrices=False)
new_rank, new_alpha, stats = _compute_resize(S, max_rank, dynamic_method, dynamic_param, scale)
U = U[:, :new_rank]
S = S[:new_rank]
Vh = Vh[:new_rank, :]
lora_up = U @ torch.diag(S)
lora_down = Vh
return {
"lora_down": lora_down.cpu().contiguous(),
"lora_up": lora_up.cpu().contiguous(),
"new_rank": new_rank,
"new_alpha": new_alpha,
**stats
}
def _extract_conv(
weight: torch.Tensor,
max_rank: int,
dynamic_method: Optional[str],
dynamic_param: Optional[float],
scale: float,
niter: int = 2,
) -> Dict:
"""Extract LoRA from merged conv weight."""
out_ch, in_ch, kh, kw = weight.shape
mat = weight.reshape(out_ch, -1)
if dynamic_method is None:
# Fixed rank - use svd_lowrank for 10x speedup
rank = min(max_rank, min(mat.shape) - 1)
U, S, Vh = torch.svd_lowrank(mat, q=rank, niter=niter)
Vh = Vh.T # svd_lowrank returns V, not Vh
new_rank = rank
new_alpha = float(scale * new_rank)
stats = {"sum_retained": 1.0, "fro_retained": 1.0} # Not computed for lowrank
else:
# Dynamic methods need full SVD to compute rank from all singular values
U, S, Vh = linalg.svd(mat, full_matrices=False)
new_rank, new_alpha, stats = _compute_resize(S, max_rank, dynamic_method, dynamic_param, scale)
U = U[:, :new_rank]
S = S[:new_rank]
Vh = Vh[:new_rank, :]
lora_up = (U @ torch.diag(S)).reshape(out_ch, new_rank, 1, 1)
lora_down = Vh.reshape(new_rank, in_ch, kh, kw)
return {
"lora_down": lora_down.cpu().contiguous(),
"lora_up": lora_up.cpu().contiguous(),
"new_rank": new_rank,
"new_alpha": new_alpha,
**stats
}
def _compute_resize(
S: torch.Tensor,
max_rank: int,
dynamic_method: Optional[str],
dynamic_param: Optional[float],
scale: float
) -> Tuple[int, float, Dict]:
"""Compute new rank and alpha based on resize method."""
if dynamic_method == "sv_ratio" and dynamic_param is not None:
# Use kohya convention: S[0]/ratio
min_sv = S[0] / dynamic_param
new_rank = max(1, int(torch.sum(S > min_sv).item()))
elif dynamic_method == "sv_cumulative" and dynamic_param is not None:
new_rank = _index_sv_cumulative(S, dynamic_param, max_rank)
elif dynamic_method == "sv_fro" and dynamic_param is not None:
new_rank = _index_sv_fro(S, dynamic_param, max_rank)
else:
new_rank = max_rank
# Clamp rank
if S[0] < MIN_SV:
new_rank = 1
else:
new_rank = max(1, min(new_rank, max_rank, len(S) - 1))
new_alpha = float(scale * new_rank)
# Compute retention stats
s_sum = float(torch.sum(torch.abs(S)))
s_rank = float(torch.sum(torch.abs(S[:new_rank]))) if new_rank <= len(S) else s_sum
S_sq = S.pow(2)
s_fro = float(torch.sqrt(torch.sum(S_sq)))
s_red_fro = float(torch.sqrt(torch.sum(S_sq[:new_rank]))) if new_rank <= len(S) else s_fro
stats = {
"sum_retained": s_rank / s_sum if s_sum > 0 else 1.0,
"fro_retained": s_red_fro / s_fro if s_fro > 0 else 1.0,
}
return new_rank, new_alpha, stats
# =============================================================================
# Main Resize Function
# =============================================================================
def resize_lora_file(
lora_path: str,
new_rank: int,
dynamic_method: Optional[str],
dynamic_param: Optional[float],
device: str,
save_dtype: torch.dtype,
output_filename: str,
verbose: bool = True,
svd_niter: int = 2,
) -> str:
"""
Resize a LoRA file to a new rank.
Args:
lora_path: Path to input LoRA
new_rank: Target rank (max rank for dynamic methods)
dynamic_method: None, "sv_ratio", "sv_fro", "sv_cumulative"
dynamic_param: Parameter for dynamic method
device: Processing device
save_dtype: Output dtype
output_filename: Output filename (without extension)
verbose: Print progress info
svd_niter: Power iterations for SVD accuracy
Returns:
Path to saved resized LoRA
"""
# Prepare memory
lora_size_gb = estimate_model_size(lora_path)
prepare_for_large_operation(lora_size_gb * 2, torch.device(device))
handler = MemoryEfficientSafeOpen(lora_path)
try:
metadata = handler.metadata().copy()
all_keys = handler.keys()
# Detect format and extract pairs
format_info = detect_lora_format(all_keys)
pairs = extract_lora_pairs(all_keys, format_info)
network_dim, network_alpha = detect_lora_rank(handler, pairs)
scale = network_alpha / network_dim if network_dim > 0 else 1.0
if verbose:
method_str = f"{dynamic_method}: {dynamic_param}" if dynamic_method else "fixed"
print(f"[LoRA Resize] Format: {format_info['format']}, layers: {format_info['key_count']}")
print(f"[LoRA Resize] Original dim={network_dim}, alpha={network_alpha:.1f}, scale={scale:.3f}")
print(f"[LoRA Resize] Resizing with method={method_str}, max_rank={new_rank}")
output_sd = {}
fro_list = []
pbar = comfy.utils.ProgressBar(len(pairs))
with torch.no_grad():
for block_name, block_keys in tqdm(pairs.items(), desc="Resizing layers", unit="layers"):
if "down" not in block_keys or "up" not in block_keys:
pbar.update(1)
continue
lora_down = handler.get_tensor(block_keys["down"])
lora_up = handler.get_tensor(block_keys["up"])
is_conv = len(lora_down.shape) == 4
# Transfer to GPU with pinned memory if available
if device == 'cuda':
lora_down = transfer_to_gpu_pinned(lora_down, device, torch.float32)
lora_up = transfer_to_gpu_pinned(lora_up, device, torch.float32)
# Merge and re-extract
if is_conv:
weight = _merge_conv(lora_down, lora_up, device)
result = _extract_conv(weight, new_rank, dynamic_method, dynamic_param, scale, svd_niter)
else:
weight = _merge_linear(lora_down, lora_up, device)
result = _extract_linear(weight, new_rank, dynamic_method, dynamic_param, scale, svd_niter)
del weight, lora_down, lora_up
fro_list.append(result['fro_retained'])
# Store using same format suffixes as input
down_suffix = format_info["down_suffix"]
up_suffix = format_info["up_suffix"]
alpha_suffix = format_info["alpha_suffix"]
# Standardize prefix using heuristics if possible
new_block_name = _format_lora_key(block_name)
output_sd[f"{new_block_name}{down_suffix}"] = result["lora_down"].to(save_dtype)
output_sd[f"{new_block_name}{up_suffix}"] = result["lora_up"].to(save_dtype)
if alpha_suffix:
output_sd[f"{new_block_name}{alpha_suffix}"] = torch.tensor(result["new_alpha"]).to(save_dtype)
del result
import gc
gc.collect()
if torch.cuda.is_available():
torch.cuda.empty_cache()
pbar.update(1)
if verbose and fro_list:
import numpy as np
avg_fro = np.mean(fro_list)
std_fro = np.std(fro_list)
print(f"[LoRA Resize] Average Frobenius retention: {avg_fro:.1%} ± {std_fro:.3f}")
# Update metadata
if dynamic_method:
metadata["ss_training_comment"] = f"Dynamic resize with {dynamic_method}: {dynamic_param} from dim {network_dim}"
metadata["ss_network_dim"] = "Dynamic"
metadata["ss_network_alpha"] = "Dynamic"
else:
metadata["ss_training_comment"] = f"Resized from dim {network_dim} to {new_rank}"
metadata["ss_network_dim"] = str(new_rank)
metadata["ss_network_alpha"] = str(scale * new_rank)
# Save
output_dir = folder_paths.get_folder_paths("loras")[0]
os.makedirs(output_dir, exist_ok=True)
output_path = os.path.join(output_dir, f"{output_filename.strip()}.safetensors")
save_file(output_sd, output_path, metadata)
print(f"[LoRA Resize] Saved to {output_path}")
return output_path
finally:
handler.__exit__(None, None, None)
cleanup_after_operation()
# =============================================================================
# Node Definitions
# =============================================================================
class LoRAResizeFixed(io.ComfyNode):
"""Resize LoRA to a fixed rank."""
@classmethod
def define_schema(cls):
return io.Schema(
node_id="LoRAResizeFixed",
display_name="LoRA Resize (Fixed Rank)",
category="ModelUtils/LoRA/Resize",
description="Resize existing LoRA to a specific rank by merging and re-extracting via SVD.",
inputs=[
io.Combo.Input("lora_name", options=folder_paths.get_filename_list("loras"),
tooltip="LoRA to resize"),
io.Int.Input("new_rank", default=64, min=1, max=3072,
tooltip="Target rank"),
io.Int.Input("svd_niter", default=2, min=0, max=10,
tooltip="SVD power iterations (higher = more accurate but slower)"),
io.String.Input("output_filename", default="resized_lora"),
io.Combo.Input("save_dtype", options=["fp16", "bf16", "fp32"], default="fp16"),
io.Combo.Input("device", options=["cuda", "cpu"], default="cuda"),
],
outputs=[io.String.Output(display_name="output_path")],
is_output_node=True,
)
@classmethod
def execute(cls, lora_name, new_rank, svd_niter, output_filename, save_dtype, device) -> io.NodeOutput:
lora_path = folder_paths.get_full_path_or_raise("loras", lora_name)
dtype = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}[save_dtype]
path = resize_lora_file(lora_path, new_rank, None, None, device, dtype, output_filename, svd_niter=svd_niter)
return io.NodeOutput(path)
class LoRAResizeRatio(io.ComfyNode):
"""Resize LoRA keeping SVs above ratio threshold."""
@classmethod
def define_schema(cls):
return io.Schema(
node_id="LoRAResizeRatio",
display_name="LoRA Resize (SV Ratio)",
category="ModelUtils/LoRA/Resize",
description="Dynamically resize LoRA, keeping singular values where S[i] > S[0]/ratio.",
inputs=[
io.Combo.Input("lora_name", options=folder_paths.get_filename_list("loras"),
tooltip="LoRA to resize"),
io.Int.Input("max_rank", default=128, min=1, max=3072,
tooltip="Maximum allowed rank"),
io.Float.Input("ratio", default=2.0, min=1.0, max=100.0, step=0.1,
tooltip="Keep SVs where S[i] > S[0]/ratio"),
io.String.Input("output_filename", default="resized_lora_ratio"),
io.Combo.Input("save_dtype", options=["fp16", "bf16", "fp32"], default="fp16"),
io.Combo.Input("device", options=["cuda", "cpu"], default="cuda"),
],
outputs=[io.String.Output(display_name="output_path")],
is_output_node=True,
)
@classmethod
def execute(cls, lora_name, max_rank, ratio, output_filename, save_dtype, device) -> io.NodeOutput:
lora_path = folder_paths.get_full_path_or_raise("loras", lora_name)
dtype = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}[save_dtype]
path = resize_lora_file(lora_path, max_rank, "sv_ratio", ratio, device, dtype, output_filename)
return io.NodeOutput(path)
class LoRAResizeFrobenius(io.ComfyNode):
"""Resize LoRA to preserve Frobenius norm target."""
@classmethod
def define_schema(cls):
return io.Schema(
node_id="LoRAResizeFrobenius",
display_name="LoRA Resize (Frobenius)",
category="ModelUtils/LoRA/Resize",
description="Dynamically resize LoRA to preserve target fraction of Frobenius norm.",
inputs=[
io.Combo.Input("lora_name", options=folder_paths.get_filename_list("loras"),
tooltip="LoRA to resize"),
io.Int.Input("max_rank", default=128, min=1, max=3072,
tooltip="Maximum allowed rank"),
io.Float.Input("target", default=0.9, min=0.1, max=1.0, step=0.01,
tooltip="Target Frobenius norm retention (0.9 = 90%)"),
io.String.Input("output_filename", default="resized_lora_fro"),
io.Combo.Input("save_dtype", options=["fp16", "bf16", "fp32"], default="fp16"),
io.Combo.Input("device", options=["cuda", "cpu"], default="cuda"),
],
outputs=[io.String.Output(display_name="output_path")],
is_output_node=True,
)
@classmethod
def execute(cls, lora_name, max_rank, target, output_filename, save_dtype, device) -> io.NodeOutput:
lora_path = folder_paths.get_full_path_or_raise("loras", lora_name)
dtype = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}[save_dtype]
path = resize_lora_file(lora_path, max_rank, "sv_fro", target, device, dtype, output_filename)
return io.NodeOutput(path)
class LoRAResizeCumulative(io.ComfyNode):
"""Resize LoRA to preserve cumulative SV target."""
@classmethod
def define_schema(cls):
return io.Schema(
node_id="LoRAResizeCumulative",
display_name="LoRA Resize (Cumulative)",
category="ModelUtils/LoRA/Resize",
description="Dynamically resize LoRA to preserve target fraction of cumulative singular values.",
inputs=[
io.Combo.Input("lora_name", options=folder_paths.get_filename_list("loras"),
tooltip="LoRA to resize"),
io.Int.Input("max_rank", default=128, min=1, max=3072,
tooltip="Maximum allowed rank"),
io.Float.Input("target", default=0.9, min=0.1, max=1.0, step=0.01,
tooltip="Target cumulative SV retention (0.9 = 90%)"),
io.String.Input("output_filename", default="resized_lora_cumulative"),
io.Combo.Input("save_dtype", options=["fp16", "bf16", "fp32"], default="fp16"),
io.Combo.Input("device", options=["cuda", "cpu"], default="cuda"),
],
outputs=[io.String.Output(display_name="output_path")],
is_output_node=True,
)
@classmethod
def execute(cls, lora_name, max_rank, target, output_filename, save_dtype, device) -> io.NodeOutput:
lora_path = folder_paths.get_full_path_or_raise("loras", lora_name)
dtype = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}[save_dtype]
path = resize_lora_file(lora_path, max_rank, "sv_cumulative", target, device, dtype, output_filename)
return io.NodeOutput(path)
# =============================================================================
# LoRA Merge To Model (Save merged model, skip extraction)
# =============================================================================
def merge_loras_to_model(
lora_paths: List[str],
lora_weights: List[float],
base_model_path: str,
device: str,
save_dtype: torch.dtype,
output_filename: str,
skip_patterns_str: str = "",
verbose: bool = True,
) -> str:
"""
Merge multiple LoRAs into a base model and save the result directly.
Unlike merge_multi_loras_via_base, this function:
- Does NOT extract the result back to a LoRA
- Saves the merged full model to the base model's directory
Args:
lora_paths: List of paths to LoRA files
lora_weights: List of weight strengths (0.0-2.0) for each LoRA
base_model_path: Path to base model
device: Processing device
save_dtype: Output dtype
output_filename: Output filename (without extension)
skip_patterns_str: Regex patterns for layers to skip
verbose: Print progress info
Returns:
Path to saved merged model
"""
# Estimate memory and prepare
total_size_gb = estimate_model_size(base_model_path)
for lp in lora_paths:
total_size_gb += estimate_model_size(lp)
if verbose:
print(f"[LoRA Merge To Model] Preparing memory for {total_size_gb:.2f}GB operation...")
print(f"[LoRA Merge To Model] Merging {len(lora_paths)} LoRAs with weights: {lora_weights}")
prepare_for_large_operation(total_size_gb * 1.5, torch.device(device))
# Open all files - use low_memory for base model to avoid OS page caching
base_handler = MemoryEfficientSafeOpen(base_model_path, low_memory=True)
lora_handlers = [MemoryEfficientSafeOpen(lp) for lp in lora_paths]
try:
# Detect format and extract pairs for each LoRA
lora_infos = []
for i, handler in enumerate(lora_handlers):
keys = handler.keys()
format_info = detect_lora_format(keys)
pairs = extract_lora_pairs(keys, format_info)
network_dim, network_alpha = detect_lora_rank(handler, pairs)
lora_infos.append({
"handler": handler,
"format_info": format_info,
"pairs": pairs,
"network_dim": network_dim,
"network_alpha": network_alpha,
"weight": lora_weights[i],
})
if verbose:
print(f"[LoRA Merge To Model] LoRA {i+1}: {format_info['format']}, {len(pairs)} layers, dim={network_dim}")
# Common prefixes
BASE_PREFIXES = ["model.diffusion_model.", "diffusion_model.", "transformer.", "model."]
LORA_PREFIXES = [
"lora_unet_", "lora_transformer_", "lora_te1_", "lora_te2_", "lora_te_",
"lycoris_", "diffusion_model.", "transformer.", "unet."
]
def extract_core_layer_base(key: str) -> str:
result = key
if result.endswith(".weight"):
result = result[:-7]
elif result.endswith(".bias"):
result = result[:-5]
for prefix in BASE_PREFIXES:
if result.startswith(prefix):
result = result[len(prefix):]
break
return result
def extract_core_layer_lora(block_name: str) -> str:
result = block_name
for prefix in LORA_PREFIXES:
if result.startswith(prefix):
result = result[len(prefix):]
break
# Strip trailing .lora suffix (HuggingFace format leaves this after suffix removal)
if result.endswith(".lora"):
result = result[:-5]
return result.replace(".", "_")
# Build LoRA lookup: core layer name (underscored) -> list of (info, block_keys)
lora_lookup = {}
for info in lora_infos:
for block_name, block_keys in info["pairs"].items():
core = extract_core_layer_lora(block_name)
if core not in lora_lookup:
lora_lookup[core] = []
lora_lookup[core].append((info, block_keys))
# Compile skip patterns
skip_patterns = _compile_patterns(skip_patterns_str)
# Preserve metadata from base model
base_metadata = base_handler.metadata().copy() if base_handler.metadata() else {}
base_metadata["merge_comment"] = f"Merged {len(lora_paths)} LoRAs with weights: {lora_weights}"
output_sd = {}
stats = {"merged": 0, "copied": 0, "skipped": 0}
base_keys = list(base_handler.keys())
pbar = comfy.utils.ProgressBar(len(base_keys))
if verbose:
print(f"[LoRA Merge To Model] Processing {len(base_keys)} base model keys...")
with torch.no_grad():
for base_key in tqdm(base_keys, desc="Merging to model", unit="keys"):
# Check skip patterns
if _matches_any_pattern(base_key, skip_patterns):
stats["skipped"] += 1
pbar.update(1)
continue
# Load base weight
cpu_base = base_handler.get_tensor(base_key)
# Only process weight tensors for LoRA merging
if base_key.endswith(".weight"):
core = extract_core_layer_base(base_key)
core_underscored = core.replace(".", "_")
# Check if any LoRA contributes to this layer
if core_underscored in lora_lookup:
# Transfer to GPU for computation
if device == 'cuda':
base_weight = transfer_to_gpu_pinned(cpu_base, device, torch.float32)
else:
base_weight = cpu_base.to(device=device, dtype=torch.float32)
del cpu_base
# Accumulate deltas from all contributing LoRAs
for info, block_keys in lora_lookup[core_underscored]:
is_full_diff = info["format_info"].get("is_full_diff", False)
if is_full_diff:
# Full diff format
if "diff" not in block_keys:
continue
cpu_diff = info["handler"].get_tensor(block_keys["diff"])
if device == 'cuda':
delta = transfer_to_gpu_pinned(cpu_diff, device, torch.float32)
else:
delta = cpu_diff.to(device=device, dtype=torch.float32)
del cpu_diff
effective_scale = info["weight"]
else:
# Standard LoRA format
if "down" not in block_keys or "up" not in block_keys:
continue
cpu_down = info["handler"].get_tensor(block_keys["down"])
cpu_up = info["handler"].get_tensor(block_keys["up"])
if device == 'cuda':
lora_down = transfer_to_gpu_pinned(cpu_down, device, torch.float32)
lora_up = transfer_to_gpu_pinned(cpu_up, device, torch.float32)
else:
lora_down = cpu_down.to(device=device, dtype=torch.float32)
lora_up = cpu_up.to(device=device, dtype=torch.float32)
del cpu_down, cpu_up
# Get alpha
if "alpha" in block_keys:
alpha_tensor = info["handler"].get_tensor(block_keys["alpha"])
layer_alpha = float(alpha_tensor.item())
else:
layer_alpha = float(info["network_dim"])
layer_scale = layer_alpha / info["network_dim"] if info["network_dim"] > 0 else 1.0
effective_scale = layer_scale * info["weight"]
# Compute delta
is_conv = len(lora_down.shape) == 4
if is_conv:
in_rank, in_size, kernel_size, k_ = lora_down.shape
out_size, out_rank, _, _ = lora_up.shape
delta = lora_up.reshape(out_size, -1) @ lora_down.reshape(in_rank, -1)
delta = delta.reshape(out_size, in_size, kernel_size, kernel_size)
else:
delta = lora_up @ lora_down
del lora_down, lora_up
# Apply delta to base weight
base_weight = base_weight + effective_scale * delta
del delta
# Store merged weight
output_sd[base_key] = base_weight.to(save_dtype).cpu().contiguous()
del base_weight
stats["merged"] += 1
else:
# No LoRA contribution, copy as-is
output_sd[base_key] = cpu_base.to(save_dtype).contiguous()
del cpu_base
stats["copied"] += 1
else:
# Non-weight tensor (bias, norm, etc.), copy as-is
output_sd[base_key] = cpu_base.to(save_dtype).contiguous()
del cpu_base
stats["copied"] += 1
import gc
gc.collect()
if torch.cuda.is_available():
torch.cuda.empty_cache()
pbar.update(1)
if verbose:
print(f"[LoRA Merge To Model] Done: {stats['merged']} merged, {stats['copied']} copied, {stats['skipped']} skipped")
# Save to base model directory
base_dir = os.path.dirname(base_model_path)
os.makedirs(base_dir, exist_ok=True)
output_path = os.path.join(base_dir, f"{output_filename.strip()}.safetensors")
save_file(output_sd, output_path, base_metadata)
print(f"[LoRA Merge To Model] Saved to {output_path}")
return output_path
finally:
base_handler.__exit__(None, None, None)
for handler in lora_handlers:
handler.__exit__(None, None, None)
cleanup_after_operation()
class LoRAMergeToModel(io.ComfyNode):
"""Merge multiple LoRAs into base model and save as full model."""
@classmethod
def define_schema(cls):
return io.Schema(
node_id="LoRAMergeToModel",
display_name="LoRA Merge To Model",
category="ModelUtils/LoRA/Merge",
description="Merge 1-8 LoRAs into a base model and save the result. Saves to base model directory.",
inputs=[
io.Combo.Input("base_model", options=folder_paths.get_filename_list("diffusion_models"),
tooltip="Base model the LoRAs were trained on"),
io.Combo.Input("lora_count", options=["1", "2", "3", "4", "5", "6", "7", "8"], default="2",
tooltip="Number of LoRAs to merge"),
# LoRA 1
io.Combo.Input("lora_1", options=folder_paths.get_filename_list("loras"),
tooltip="First LoRA"),
io.Float.Input("weight_1", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 1"),
# LoRA 2
io.Combo.Input("lora_2", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Second LoRA"),
io.Float.Input("weight_2", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 2"),
# LoRA 3
io.Combo.Input("lora_3", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Third LoRA"),
io.Float.Input("weight_3", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 3"),
# LoRA 4
io.Combo.Input("lora_4", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Fourth LoRA"),
io.Float.Input("weight_4", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 4"),
# LoRA 5
io.Combo.Input("lora_5", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Fifth LoRA"),
io.Float.Input("weight_5", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 5"),
# LoRA 6
io.Combo.Input("lora_6", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Sixth LoRA"),
io.Float.Input("weight_6", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 6"),
# LoRA 7
io.Combo.Input("lora_7", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Seventh LoRA"),
io.Float.Input("weight_7", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 7"),
# LoRA 8
io.Combo.Input("lora_8", options=["None"] + folder_paths.get_filename_list("loras"),
default="None", tooltip="Eighth LoRA"),
io.Float.Input("weight_8", default=1.0, min=-10.0, max=10.0, step=0.01,
tooltip="Weight strength for LoRA 8"),
# Settings
io.String.Input("skip_patterns", default="", multiline=True,
tooltip="Regex patterns for layers to skip"),
io.String.Input("output_filename", default="merged_model"),
io.Combo.Input("save_dtype", options=["fp16", "bf16", "fp32"], default="fp16"),
io.Combo.Input("device", options=["cuda", "cpu"], default="cuda"),
],
outputs=[io.String.Output(display_name="output_path")],
is_output_node=True,
)
@classmethod
def execute(cls, base_model, lora_count,
lora_1, weight_1, lora_2, weight_2, lora_3, weight_3, lora_4, weight_4,
lora_5, weight_5, lora_6, weight_6, lora_7, weight_7, lora_8, weight_8,
skip_patterns, output_filename, save_dtype, device) -> io.NodeOutput:
# Build LoRA list based on count
count = int(lora_count)
lora_names = [lora_1, lora_2, lora_3, lora_4, lora_5, lora_6, lora_7, lora_8][:count]
lora_weights = [weight_1, weight_2, weight_3, weight_4, weight_5, weight_6, weight_7, weight_8][:count]
# Filter out "None" entries
valid_loras = [(name, weight) for name, weight in zip(lora_names, lora_weights) if name != "None"]
if not valid_loras:
raise ValueError("At least one LoRA must be selected")
lora_names, lora_weights = zip(*valid_loras)
lora_paths = [folder_paths.get_full_path_or_raise("loras", name) for name in lora_names]
base_path = folder_paths.get_full_path_or_raise("diffusion_models", base_model)
dtype = {"fp16": torch.float16, "bf16": torch.bfloat16, "fp32": torch.float32}[save_dtype]
path = merge_loras_to_model(
lora_paths=list(lora_paths),
lora_weights=list(lora_weights),
base_model_path=base_path,
device=device,
save_dtype=dtype,
output_filename=output_filename,
skip_patterns_str=skip_patterns,
)
return io.NodeOutput(path)