masked_approximation_impl {fastadi} | R Documentation |
Expand an SVD only at observed values of a sparse matrix
Description
TODO: describe what it looks like for dimensions to match up between
s
and mask
. See vignette("sparse-computations")
for mathematical
details.
Usage
masked_approximation_impl(U, V, row, col)
Arguments
U |
Low-rank matrix of left singular-ish vectors. |
V |
Low-rank matrix of right singular-ish vectors. |
row |
Zero-based row indices of observed elements. |
col |
Zero-based col indices of observed elements. |
Details
The idea is to populate U
, d
and V
with using the
elements of an SVD-like list. You can generate row
and col
most easily from a sparse masking Matrix (Matrix package),
coercing to triplet format, and extracting mask@i
for row
and mask@j
for column.
Value
A sparse matrix representing the low-rank reconstruction
from U
, d
and V
, only at the index pairs indicated by
row
and col
.
[Package fastadi version 0.1.2 Index]