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<div class="section" id="tabprm">
<h1>Tabprm<a class="headerlink" href="#tabprm" title="Permalink to this headline">¶</a></h1>
<dl class="class">
<dt id="astropy.wcs.Tabprm">
<em class="property">class </em><tt class="descclassname">astropy.wcs.</tt><tt class="descname">Tabprm</tt><a class="headerlink" href="#astropy.wcs.Tabprm" title="Permalink to this definition">¶</a></dt>
<dd><p>Bases: <tt class="xref py py-class docutils literal"><span class="pre">object</span></tt></p>
<p>A class to store the information related to tabular coordinates,
i.e., coordinates that are defined via a lookup table.</p>
<p>This class can not be constructed directly from Python, but instead is
returned from <a class="reference internal" href="astropy.wcs.Wcsprm.html#astropy.wcs.Wcsprm.tab" title="astropy.wcs.Wcsprm.tab"><tt class="xref py py-obj docutils literal"><span class="pre">tab</span></tt></a>.</p>
<p class="rubric">Attributes Summary</p>
<table border="1" class="longtable docutils">
<colgroup>
<col width="10%" />
<col width="90%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.K" title="astropy.wcs.Tabprm.K"><tt class="xref py py-obj docutils literal"><span class="pre">K</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> (read-only) The lengths of the axes of the coordinate</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.M" title="astropy.wcs.Tabprm.M"><tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span></tt> (read-only) Number of tabular coordinate axes.</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.coord" title="astropy.wcs.Tabprm.coord"><tt class="xref py py-obj docutils literal"><span class="pre">coord</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[K_M]...[K_2][K_1][M]</span></tt> The tabular coordinate array.</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.crval" title="astropy.wcs.Tabprm.crval"><tt class="xref py py-obj docutils literal"><span class="pre">crval</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[M]</span></tt> Index values for the reference pixel for each of</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.delta" title="astropy.wcs.Tabprm.delta"><tt class="xref py py-obj docutils literal"><span class="pre">delta</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[M]</span></tt> (read-only) Interpolated indices into the coord</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.extrema" title="astropy.wcs.Tabprm.extrema"><tt class="xref py py-obj docutils literal"><span class="pre">extrema</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[K_M]...[K_2][2][M]</span></tt> (read-only)</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.map" title="astropy.wcs.Tabprm.map"><tt class="xref py py-obj docutils literal"><span class="pre">map</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> Association between axes.</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.nc" title="astropy.wcs.Tabprm.nc"><tt class="xref py py-obj docutils literal"><span class="pre">nc</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span></tt> (read-only) Total number of coord vectors in the coord array.</td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.p0" title="astropy.wcs.Tabprm.p0"><tt class="xref py py-obj docutils literal"><span class="pre">p0</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> Interpolated indices into the coordinate array.</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.sense" title="astropy.wcs.Tabprm.sense"><tt class="xref py py-obj docutils literal"><span class="pre">sense</span></tt></a></td>
<td><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> +1 if monotonically increasing, -1 if decreasing.</td>
</tr>
</tbody>
</table>
<p class="rubric">Methods Summary</p>
<table border="1" class="longtable docutils">
<colgroup>
<col width="10%" />
<col width="90%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td><a class="reference internal" href="#astropy.wcs.Tabprm.print_contents" title="astropy.wcs.Tabprm.print_contents"><tt class="xref py py-obj docutils literal"><span class="pre">print_contents</span></tt></a>()</td>
<td>Print the contents of the <tt class="xref py py-obj docutils literal"><span class="pre">Tabprm</span></tt> object to stdout.</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#astropy.wcs.Tabprm.set" title="astropy.wcs.Tabprm.set"><tt class="xref py py-obj docutils literal"><span class="pre">set</span></tt></a>()</td>
<td>Allocates memory for work arrays.</td>
</tr>
</tbody>
</table>
<p class="rubric">Attributes Documentation</p>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.K">
<tt class="descname">K</tt><a class="headerlink" href="#astropy.wcs.Tabprm.K" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> (read-only) The lengths of the axes of the coordinate
array.</p>
<p>An array of length <a class="reference internal" href="#astropy.wcs.Tabprm.M" title="astropy.wcs.Tabprm.M"><tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt></a> whose elements record the lengths of the axes of
the coordinate array and of each indexing vector.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.M">
<tt class="descname">M</tt><a class="headerlink" href="#astropy.wcs.Tabprm.M" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span></tt> (read-only) Number of tabular coordinate axes.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.coord">
<tt class="descname">coord</tt><a class="headerlink" href="#astropy.wcs.Tabprm.coord" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[K_M]...[K_2][K_1][M]</span></tt> The tabular coordinate array.</p>
<p>Has the dimensions:</p>
<div class="highlight-python"><pre>(K_M, ... K_2, K_1, M)</pre>
</div>
<p>(see <tt class="xref py py-obj docutils literal"><span class="pre">K</span></tt>) i.e. with the <a class="reference internal" href="#astropy.wcs.Tabprm.M" title="astropy.wcs.Tabprm.M"><tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt></a> dimension
varying fastest so that the <a class="reference internal" href="#astropy.wcs.Tabprm.M" title="astropy.wcs.Tabprm.M"><tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt></a> elements of a coordinate vector are
stored contiguously in memory.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.crval">
<tt class="descname">crval</tt><a class="headerlink" href="#astropy.wcs.Tabprm.crval" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[M]</span></tt> Index values for the reference pixel for each of
the tabular coord axes.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.delta">
<tt class="descname">delta</tt><a class="headerlink" href="#astropy.wcs.Tabprm.delta" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[M]</span></tt> (read-only) Interpolated indices into the coord
array.</p>
<p>Array of interpolated indices into the coordinate array such that
Upsilon_m, as defined in Paper III, is equal to
(<tt class="xref py py-obj docutils literal"><span class="pre">p0</span></tt> [m] + 1) + delta[m].</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.extrema">
<tt class="descname">extrema</tt><a class="headerlink" href="#astropy.wcs.Tabprm.extrema" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">double</span> <span class="pre">array[K_M]...[K_2][2][M]</span></tt> (read-only)</p>
<p>An array recording the minimum and maximum value of each element of
the coordinate vector in each row of the coordinate array, with the
dimensions:</p>
<div class="highlight-python"><pre>(K_M, ... K_2, 2, M)</pre>
</div>
<p>(see <tt class="xref py py-obj docutils literal"><span class="pre">K</span></tt>). The minimum is recorded
in the first element of the compressed K_1 dimension, then the
maximum. This array is used by the inverse table lookup function to
speed up table searches.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.map">
<tt class="descname">map</tt><a class="headerlink" href="#astropy.wcs.Tabprm.map" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> Association between axes.</p>
<p>A vector of length <tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt> that defines
the association between axis <em>m</em> in the <em>M</em>-dimensional coordinate
array (1 <= <em>m</em> <= <em>M</em>) and the indices of the intermediate world
coordinate and world coordinate arrays.</p>
<p>When the intermediate and world coordinate arrays contain the full
complement of coordinate elements in image-order, as will usually be
the case, then <tt class="docutils literal"><span class="pre">map[m-1]</span> <span class="pre">==</span> <span class="pre">i-1</span></tt> for axis <em>i</em> in the <em>N</em>-dimensional
image (1 <= <em>i</em> <= <em>N</em>). In terms of the FITS keywords:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="nb">map</span><span class="p">[</span><span class="n">PVi_3a</span> <span class="o">-</span> <span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="n">i</span> <span class="o">-</span> <span class="mf">1.</span>
</pre></div>
</div>
<p>However, a different association may result if the intermediate
coordinates, for example, only contains a (relevant) subset of
intermediate world coordinate elements. For example, if <em>M</em> == 1 for
an image with <em>N</em> > 1, it is possible to fill the intermediate
coordinates with the relevant coordinate element with <tt class="docutils literal"><span class="pre">nelem</span></tt> set to
1. In this case <tt class="docutils literal"><span class="pre">map[0]</span> <span class="pre">=</span> <span class="pre">0</span></tt> regardless of the value of <em>i</em>.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.nc">
<tt class="descname">nc</tt><a class="headerlink" href="#astropy.wcs.Tabprm.nc" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span></tt> (read-only) Total number of coord vectors in the coord array.</p>
<p>Total number of coordinate vectors in the coordinate array being the
product K_1 * K_2 * ... * K_M.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.p0">
<tt class="descname">p0</tt><a class="headerlink" href="#astropy.wcs.Tabprm.p0" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> Interpolated indices into the coordinate array.</p>
<p>Vector of length <tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt> of interpolated
indices into the coordinate array such that Upsilon_m, as defined in
Paper III, is equal to <tt class="docutils literal"><span class="pre">(p0[m]</span> <span class="pre">+</span> <span class="pre">1)</span> <span class="pre">+</span> <span class="pre">delta[m]</span></tt>.</p>
</dd></dl>
<dl class="attribute">
<dt id="astropy.wcs.Tabprm.sense">
<tt class="descname">sense</tt><a class="headerlink" href="#astropy.wcs.Tabprm.sense" title="Permalink to this definition">¶</a></dt>
<dd><p><tt class="docutils literal"><span class="pre">int</span> <span class="pre">array[M]</span></tt> +1 if monotonically increasing, -1 if decreasing.</p>
<p>A vector of length <tt class="xref py py-obj docutils literal"><span class="pre">M</span></tt> whose elements
indicate whether the corresponding indexing vector is monotonically
increasing (+1), or decreasing (-1).</p>
</dd></dl>
<p class="rubric">Methods Documentation</p>
<dl class="method">
<dt id="astropy.wcs.Tabprm.print_contents">
<tt class="descname">print_contents</tt><big>(</big><big>)</big><a class="headerlink" href="#astropy.wcs.Tabprm.print_contents" title="Permalink to this definition">¶</a></dt>
<dd><p>Print the contents of the <tt class="xref py py-obj docutils literal"><span class="pre">Tabprm</span></tt> object to
stdout. Probably only useful for debugging purposes, and may be
removed in the future.</p>
<p>To get a string of the contents, use <tt class="xref py py-obj docutils literal"><span class="pre">repr</span></tt>.</p>
</dd></dl>
<dl class="method">
<dt id="astropy.wcs.Tabprm.set">
<tt class="descname">set</tt><big>(</big><big>)</big><a class="headerlink" href="#astropy.wcs.Tabprm.set" title="Permalink to this definition">¶</a></dt>
<dd><p>Allocates memory for work arrays.</p>
<p>Also sets up the class according to information supplied within it.</p>
<p>Note that this routine need not be called directly; it will be invoked
by functions that need it.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Raises :</th><td class="field-body"><p class="first"><strong>MemoryError</strong> :</p>
<blockquote>
<div><p>Memory allocation failed.</p>
</div></blockquote>
<p><strong>InvalidTabularParameters</strong> :</p>
<blockquote class="last">
<div><p>Invalid tabular parameters.</p>
</div></blockquote>
</td>
</tr>
</tbody>
</table>
</dd></dl>
</dd></dl>
</div>
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