Q1 · What is being condensed, for which learner?
Settings
The same method family can be applied to very different data. A setting fixes what one synthetic sample is, how the budget is counted, and how the result is evaluated. Those three facts decide which numbers can be compared.
Unimodal images
Multimodal data
Image–text pairs (vision–language)
13Condense a paired image–caption corpus so that a dual encoder trained on the synthetic pairs retrieves nearly as well as one trained on the full corpus.
Budget: number of image–text pairs (typically 100–1000)
Audio–visual and omnimodal data
4Condense datasets whose samples span audio, vision and sometimes further modalities, while preserving the correspondence between them.
Budget: samples per class
Other data types
Video
11Condense video datasets for action recognition or temporal understanding, where most of the cost and most of the redundancy lie in the time axis.
Budget: clips per class
Graphs
23Graph condensation: synthesize a small graph (or a few small graphs) on which a graph neural network trains to the accuracy it reaches on the original large graph.
Budget: condensation ratio (fraction of nodes kept)
Text and language models
13Condense text datasets for classifiers or language-model fine-tuning, where the discreteness of tokens breaks the gradient-based synthesis that works for pixels.
Budget: examples per class
Time series and spatio-temporal data
8Condense sequential datasets for forecasting or classification, where the target is often a regression output rather than a class label.
Budget: number of synthetic sequences or windows
Other data types
27Point clouds, tabular data, recommender interactions, speech, EEG, event streams, reinforcement learning and more, each with a handful of papers adapting condensation to its structure.
Budget: domain-specific
Beyond classification
Pre-training, transfer and foundation models
9Condense unlabeled data for self-supervised pre-training, or condense data for training on top of frozen pretrained models, and judge the result by transfer rather than by in-distribution accuracy.
Budget: number of images
Detection, segmentation and low-level vision
7Condense datasets whose labels are spatial (boxes, masks, target images), where one image holds many objects and synthesis must preserve layout.
Budget: number of images, or a fraction of the training set