transform.value.text

17 significant decimal digits identify a double uniquely, so writing that many of them and
reading them back preserves the value exactly -- but only if the decimal conversion of the C library rounds
correctly, and that is not true on every platform: on macOS (ARM64) the round trip of a value like
<code>-1e-7 / 7</code> loses one unit in the last place, because the value that is written is one digit off. The round
trip is therefore verified here with R's own decimal conversion, and the number of digits is increased
until the value survives it. The output therefore has no more digits than the platform can handle
correctly, and it is guaranteed to be read back exactly by the same platform.

internal

Provides functions to read and write neuroimaging data in various file formats, with a focus on 'FreeSurfer' formats. This includes, but is not limited to, the following file formats: 1) MGH/MGZ/NIFTI format files, which can contain multi-dimensional images or other data. Typically they contain time-series of three-dimensional brain scans acquired by magnetic resonance imaging (MRI). They can also contain vertex-wise measures of surface morphometry data. The MGH format is named after the Massachusetts General Hospital, and the MGZ format is a compressed version of the same format. 2) 'FreeSurfer' morphometry data files in binary 'curv' format. These contain vertex-wise surface measures, i.e., one scalar value for each vertex of a brain surface mesh. These are typically values like the cortical thickness or brain surface area at each vertex. 3) Annotation file format. This contains a brain surface parcellation derived from a cortical atlas. 4) Surface file format. Contains a brain surface mesh, given by a list of vertices and a list of faces.

Tim Schc3<a4>fer

freesurferformats

Read and Write 'FreeSurfer' Neuroimaging File Formats

Tim Schäfer

Van Essen Lab 

Montreal Neurological Institute (MNI) 

transform.value.text function

<dl><dt>value</dt>
<dd>single numerical value, the value to format.</dd></dl>

Arguments

Format a single numerical value for a transformation text file. — transform.value.text

<dl>

<dt>value</dt>
<dd>single numerical value, the value to format.</dd>

</dl>

transform.value.text: Format a single numerical value for a transformation text file.

Description

Usage

Value

Arguments