`h5_read_plan()` estimates the physical HDF5 chunks touched by a logical observation-by-feature selection. It uses descriptor metadata only and does not open or read the dataset. `validate_h5_read_amplification()` turns the estimate into an executable performance gate.
Usage
h5_read_plan(x, observations = NULL, features = NULL)
validate_h5_read_amplification(plan, max = 1.5)Arguments
- x
An `h5_array_source` descriptor.
- observations, features
Logical selectors accepted by [fmridataset::source_read()]. Duplicate positions do not cause additional physical reads.
- plan
A plan returned by `h5_read_plan()`.
- max
Maximum permitted ratio of physically touched values to unique requested values.