super_partition implements the agglomerative, data reduction method Partition for datasets with large numbers of features by first 'super-partitioning' the data into smaller clusters to Partition.
super_partition(
full_data,
threshold = 0.5,
cluster_size = 4000,
partitioner = part_icc(),
tolerance = 1e-04,
niter = NULL,
x = "reduced_var",
.sep = "_",
verbose = TRUE,
progress_bar = TRUE
)sample by feature data frame or matrix
the minimum proportion of information explained by a reduced variable; threshold sets a boundary for information loss because each reduced variable must explain at least as much as threshold as measured by the metric.
maximum size of any single cluster; default is 4000
a partitioner. See the part_*() functions and as_partitioner().
a small tolerance within the threshold; if a reduction is within the threshold plus/minus the tolerance, it will reduce.
the number of iterations. By default, it is calculated as 20% of the number of variables or 10, whichever is larger.
the prefix of the new variable names; must not be contained in any existing data names
a character vector that separates x from the number (e.g. "reduced_var_1").
logical for whether or not to display information about super partition step; default is TRUE
logical for whether or not to show progress bar; default is TRUE
Partition object
super_partition scales up partition with an approximation, using Genie, a fast, hierarchical clustering algorithm with similar qualities of those to Partition, to first super-partition the data into ceiling(N/c) clusters, where N is the number of features in the full dataset and c is the user-defined maximum cluster size (default value = 4,000). Then, if any cluster from the super-partition has a size greater than c, use Genie again on that cluster until all cluster sizes are less than c. Finally, apply the Partition algorithm to each of the super-partitions.
It may be the case that large super-partitions cannot be easily broken with Genie due to high similarity between features. In this case, we use k-means to break the cluster.
Barrett, Malcolm and Joshua Millstein (2020). partition: A fast and flexible framework for data reduction in R. Journal of Open Source Software, 5(47), 1991, https://doi.org/10.21105/joss.01991Millstein J, Battaglin F, Barrett M, Cao S, Zhang W, Stintzing S, et al. Partition: a surjective mapping approach for dimensionality reduction. Bioinformatics 36 (2019) 676–681. doi:10.1093/bioinformatics/btz661.
Gagolewski, Marek, Maciej Bartoszuk, and Anna Cena. "Genie: A new, fast, and outlier-resistant hierarchical clustering algorithm." Information Sciences 363 (2016): 8-23.
Millstein, Joshua, Francesca Battaglin, Malcolm Barrett, Shu Cao, Wu Zhang, Sebastian Stintzing, Volker Heinemann, and Heinz-Josef Lenz. 2020. “Partition: A Surjective Mapping Approach for Dimensionality Reduction.” Bioinformatics 36 (3): https://doi.org/676–81.10.1093/bioinformatics/btz661.
set.seed(123)
df <- simulate_block_data(c(15, 20, 10), lower_corr = .4, upper_corr = .6, n = 100)
# don't accept reductions where information < .6
prt <- super_partition(df, threshold = .6, cluster_size = 30)
#> 2 super clusters identified. Beginning Partition.
#> Maximum cluster size: 30
prt
#> Partitioner:
#> Director: Minimum Distance (Pearson)
#> Metric: Intraclass Correlation
#> Reducer: Scaled Mean
#>
#> Reduced Variables:
#> 9 reduced variables created from 32 observed variables
#>
#> Mappings:
#> reduced_var_1 = {block2_x2, block2_x3, block2_x4, block2_x5, block2_x7, and 6 more variables}
#> reduced_var_2 = {block2_x12, block2_x14}
#> reduced_var_3 = {block3_x1, block3_x8, block3_x9}
#> reduced_var_4 = {block2_x6, block2_x15}
#> reduced_var_5 = {block3_x4, block3_x5}
#> reduced_var_6 = {block1_x1, block1_x2, block1_x7, block1_x11, block1_x14}
#> reduced_var_7 = {block1_x4, block1_x10, block1_x15}
#> reduced_var_8 = {block1_x8, block1_x12}
#> reduced_var_9 = {block1_x3, block1_x6}
#>
#> Minimum information:
#> 0.601