mvl_close

Closes MVL file releasing all resources.
For read-only files the memory is unmapped, reducing the virtual memory footprint.
For files opened for writing the directory is written out, so it is important to call <code>mvl_close</code> or the newly written file will be corrupt.
After <code>mvl_close()</code> all previously obtained MVL_OBJECT's with this handle become invalid.

Mappable vector library provides convenient way to access large datasets. Use all of your data at once, with few limits. Memory mapped data can be shared between multiple R processes. Access speed depends on storage medium, so solid state drive is recommended, preferably with PCI Express (or M.2 nvme) interface or a fast network file system. The data is memory mapped into R and then accessed using usual R list and array subscription operators. Convenience functions are provided for merging, grouping and indexing large vectors and data.frames. The layout of underlying MVL files is optimized for large datasets. The vectors are stored to guarantee alignment for vector intrinsics after memory map. The package is built on top of libMVL, which can be used as a standalone C library. libMVL has simple C API making it easy to interchange datasets with outside programs. Large MVL datasets are distributed via Academic Torrents <https://academictorrents.com/collection/mvl-datasets>.

Vladimir Dergachev

RMVL

Mappable Vector Library for Handling Large Datasets

mvl_close function

<dl><dt>MVLHANDLE</dt>
<dd>handle to opened MVL file as generated by mvl_open()</dd>
<dt>checksums</dt>
<dd>set to true to compute and write checksums. Checksums are computing by rereading data in the MVL file which can increase I/O for temporary files. We recommend to always include checksums into final output files as file size increase is very small (1/8192 fraction).</dd></dl>

Arguments

Close MVL file — mvl_close

<dl>

<dt>MVLHANDLE</dt>
<dd>handle to opened MVL file as generated by mvl_open()</dd>


<dt>checksums</dt>
<dd>set to true to compute and write checksums. Checksums are computing by rereading data in the MVL file which can increase I/O for temporary files. We recommend to always include checksums into final output files as file size increase is very small (1/8192 fraction).</dd>

</dl>

mvl_close: Close MVL file

Description

Usage

Value

Arguments

Details

See Also