Organizations: School of Computer Science and Engineering, Southeast University, Nanjing, China and the Key Laboratory of New Generation Artificial Intelligence Technology and Its Interdisciplinary Applications (Southeast University), Ministry of Education, China
Large-scale pre-trained models have become foundational to modern machine learning, yet conventional pre-training objectives primarily optimize source-domain performance without explicitly considering downstream requirements. Consequently, transferable and task-specific knowledge remains entangled within a shared parameter space, limiting selective knowledge reuse and efficient downstream adaptation. This limitation is particularly consequential for image-generation models, which must accommodate diverse conditions and domains. To address this challenge, we introduce Knowledge Diversion (KDiv), a condition-aware pre-training paradigm for learning inherently decomposable generative models. Before pre-training, KDiv factorizes randomly initialized weights into rank-one Knowledge Units, which are organized into learngenes and tailors. During pre-training, continuous condition-aware routing consolidates knowledge shared across conditions in learngenes while directing condition-dependent variations to tailors. This structured organization enables learngenes to capture transferable generative priors and tailors to develop condition-specific expertise, allowing the resulting model to be selectively recombined for diverse downstream conditions. Extensive experiments across class-, text-, and image-conditioned generation demonstrate that KDiv consistently matches or surpasses dense baselines at comparable pre-training cost and achieves the strongest average downstream performance with a trainable parameter budget comparable to low-rank adaptation methods.
Figures & tables
Fig. 1: (a) Conventional pre-training entangles transferable and source-specific knowledge within a unified backbone, forcing limited downstream updates to both mitigate source-domain bias and capture target-specific variation. (b) KDiv separates condition-agnostic knowledge into shared learngenes and condition-specific knowledge into tailors during pre-training, enabling target models to recombine the shared prior with relevant specialized components. This structured recombination concentrates adaptation on target-specific knowledge and improves alignment with the target distribution.
Fig. 2: Overview of the KDiv framework. KDiv factorizes the principal weight matrices of each DiT block into rank-one Knowledge Units and partitions them into condition-agnostic learngenes and condition-specific tailors. Modality-specific encoders and continuous gating predict tailor modulation values, which combine the dynamically weighted tailors with the always-active learngenes to reconstruct condition-specific weights. This unified formulation supports class-, text-, and image-conditioned generation under the diffusion training objective.
Fig. 3: Qualitative comparison on novel downstream conditions. Representative samples generated by KDiv and competing PEFT methods for Class-Conditional Generation (C2I) , Text-Conditional Generation (T2I) , and Image-Conditional Generation (I2I) tasks. Additional qualitative comparisons are provided in Appendix Figs. 12 and 13 .
Class-Conditional Generation (C2I)
CUB-200
DF20M
Flowers-102
Food-101
Cost
FDD ↓
KDD ↓
CMMD ↓
FDD ↓
KDD ↓
CMMD ↓
FDD ↓
KDD ↓
CMMD ↓
FDD ↓
KDD ↓
CMMD ↓
GPU Time
Param.
SVDiff [ 22 ]
1987
3.775
1.597
1878
6.332
2.378
2083
3.510
1.587
1594
3.832
2.690
0.92 h
0.02M
OFT [ 54 ]
1130
1.452
0.635
977
3.213
1.366
1651
1.992
1.175
1290
2.979
2.217
1.26 h
15.03M
LoRA [ 4 ]
1095
1.313
0.535
1053
3.544
1.387
1575
1.674
0.889
1245
2.835
2.007
1.13 h
11.80M
PiSSA [ 55 ]
1051
1.230
0.531
930
3.089
1.263
1596
1.767
0.973
1208
2.697
1.964
1.14 h
11.80M
TABLE II: Performance of knowledge diversion in adapting to novel conditions. We compare KDiv with parameter-efficient adaptation methods on previously unseen downstream conditions. Performance is evaluated using FDD ( ↓ ), KDD ( ↓ ), and CMMD ( ↓ ) for C2I, and LPIPS ( ↓ ), SSIM ( ↑ ), and CLIP-T/CLIP-I ( ↑ ) for T2I/I2I, respectively. “GPU Time” denotes the adaptation cost, and “Param.” denotes the average number of trainable parameters.
Fig. 4: Downstream learning efficiency of KDiv. (a) Training loss curves across eight Text-Conditional Generation (T2I) datasets. (b) Qualitative evolution of Class-Conditional Generation (C2I) samples at 5K, 10K, 30K, and 50K training steps. Compared with representative PEFT baselines, KDiv exhibits faster convergence and produces high-quality samples at earlier adaptation stages. Additional results are provided in Appendix Fig. 14 .
Class-Conditional Generation (C2I)
Routing
Downstream Adaptation
Method
LG
Tailor
Exclusive
Overlapping
FDD ↓
KDD ↓
CMMD ↓
Baseline
1119
2.656
1.514
Only LG
✓
1030
2.382
1.392
KIND
✓
✓
✓
983
2.287
1.299
KDiv
✓
✓
✓
966
2.239
1.190
TABLE III: Ablation study of knowledge diversion for downstream adaptation. “LG” is the abbreviation for learngene, while “Exclusive” and “Overlapping” refer to the tailor-routing strategies adopted by KIND and KDiv, respectively. “N/A” denotes failure under the corresponding task setting.
Fig. 5: Emergent orthogonality among tailors. (a) Distributions of pairwise angular deviations from 90∘ across C2I, I2I, and T2I. (b) Fractions of tailor pairs satisfying different orthogonality thresholds. (c) Learned U and V matrices from representative FCin and FCout layers. Together, these results reveal consistently strong tailor orthogonality across conditioning modalities.
Fig. 6: Effect of tailor rank on downstream adaptation. Comparison of KDiv and LoRA at different ranks on T2I using LPIPS ↓ , SSIM ↑ , and CLIP-T ↑ . Curves report generation performance, while bars indicate active parameters. KDiv consistently achieves superior performance with fewer active parameters.
Fig. 7: Effect of the learngene allocation on generation performance. Relative improvements in FID and IS over dense training as the proportion of learngenes varies in C2I. A 25% learngene ratio achieves the largest gains, whereas allocating all Knowledge Units to learngenes removes condition-specific routing and recovers the dense baseline.
Fig. 8: Condition relationships captured by the gating network. Pairwise cosine similarities between the tailor modulation vectors σTc predicted by Eq. ( 9 ) for conditions in (a) C2I, (b) T2I, and (c) I2I. The resulting similarity structures demonstrate that the gating network captures relationships among conditions, enabling the adaptive activation and reuse of relevant tailors.
Fig. 9: Visualization of KDiv with and without tailors (i.e., learngenes only) across 15 classes and three random seeds. Learngene-only generation exhibits semantic invariance, reflecting a condition-agnostic prior, whereas tailors inject condition-specific knowledge for semantically aligned generation. Additional qualitative results are provided in Appendix Fig. 10 .
TABLE IV: Datasets used for pre-training and downstream adaptation.
Training Settings
Class-Conditional Gen.
Text-Conditional Gen.
Image-Conditional Gen.
Optimizer
AdamW
AdamW
AdamW
Learning rate
1×10−4
1×10−4
1×10−5
Weight decay
0
0.03
0.03
Warmup steps
0
100
0
LR scheduler
Constant
Constant (400K) + cosine decay (100K)
Constant
Batch size
256
256
16
Appendix
TABLE V: Hyperparameter configurations for pre-training decomposable models with KDiv.
Level
Hyperparameter
Class-Conditional Gen.
Text-Conditional Gen.
Image-Conditional Gen.
Task Level
Batch size
256
32
4
Training steps
50,000
3,000
3,000
Optimizer
AdamW
AdamW
AdamW
Weight decay
0
0.03
0.03
LR scheduler
Constant
Constant
Constant
Warmup steps
0
0
0
Appendix
TABLE VI: Hyperparameter configurations for downstream adaptation. Task-level training settings and method-specific configurations used to evaluate KDiv and competing PEFT methods across class-, text-, and image-conditioned generation.
Fig. 10: Additional visualization of condition-agnostic knowledge in learngenes. Learngene-only outputs exhibit no condition-specific semantics, reflecting the condition-agnostic knowledge encoded by learngenes, whereas incorporating tailors introduces the semantics required for condition-aligned generation.
Fig. 11: Zero-shot generalization to unseen image conditions. Qualitative comparison of the dense baseline and KDiv under unseen Inpainting , Lineart , and Illusion conditions without downstream adaptation. KDiv demonstrates stronger condition adherence and better preserves the semantic content and spatial structure of the reference images.
Fig. 12: Additional qualitative comparisons on downstream Class- and Text-Conditional Generation tasks.
Fig. 13: Additional qualitative comparisons on downstream Image-Conditional Generation tasks.
Fig. 14: Additional qualitative evolution of Class-Conditional Generation (C2I) samples at 10K-step training intervals.