(sw-qgrid)=

# sw_qgrid

## Syntax
  
`qgrid = sw_qgrid(Name,Value)`
  
## Description
  
`qgrid = sw_qgrid(Name,Value)` generates n-dimensional grids ($n<=3$) in
3D space, e.g. points on a line in 3D. It uses $n$ linearly independent
vectors ("lattice vectors") and bin values (coordinates in "lattice
units" or "lu") to generate the points. It works similarly as the d3d
constructor in [Horace](http://horace.isis.rl.ac.uk/Main_Page).
  
## Name-Value Pair Arguments
  
`'u'`
:  Row vector with 3 elements, determines the first axis in 3D
   space, default value is `[1 0 0]`.
  
`'v'`
:  Second axis, default value is `[0 1 0]`.
  
`'w'`
:  Third axis, default value is `[0 0 1]`.
  
`'uoffset'`
:  Row vector with 3 elements, determines the offset of origin
   in lu, (fourth element is accepted but discarded).
  
`'ubin'`
:  Bin points along the first axis. Can be a vector with 1, 2 or 3
   elements:
 
   * `[B1]`        single value along the $u$-axis at a coordinate of `B1*u`
   * `[B1 B2]`     range along the $u$-axis at coordinates of `[B1:1/nExt:B2]*u`
   * `[B1 dB B2]`  range along the $u$-axis at coordinates of `[B1:dB:B2]*u`
  
`'vbin'`
:  Same as `ubin` but along the $v$-axis.
  
`'wbin'`
:  Same as `ubin` but along the $w$-axis.
  
`'nExt'`
:  Vector with $n$-elements that can define fractional bin steps,
   default values is `[1 1 1]`.
  
`'lab'`
:  Cell array of projection axis labels with 3 elements (4th
   element discarded), e.g. `{'x' 'y' 'z'}`.
  
The dimension count $n$ is determined by the number of given bins
($1<=n<=3$), so if only `ubin` is given, $n=1$; if both `ubin` and `vbin`
are defined then $n=2$, etc.
  
`'fid'`
: Defines whether to provide text output. The default value is determined
  by the `fid` preference stored in [swpref](#swpref). The possible values are:
  * `0`   No text output is generated.
  * `1`   Text output in the MATLAB Command Window.
  * `fid` File ID provided by the `fopen` command, the output is written
          into the opened file stream.
 
## Output Arguments
  
`qGrid`
: A matrix with dimensions of $[3\times n_{ax1}\times n_{ax2},...]$,
  where $n_{axi}$ is the index of points along $i$th axis with $1<=i<=n$.
  
## See Also
  
[sw_qscan](#sw-qscan)