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<h1 id="shread2">SHRead2</h1>
<p>Read spherical harmonic coefficients from a CHAMP or GRACE-like ascii-formatted file.</p>
<h1 id="usage">Usage</h1>
<p>call SHRead2 (<code>filename</code>, <code>cilm</code>, <code>lmax</code>, <code>gm</code>, <code>r0_pot</code>, <code>error</code>, <code>dot</code>, <code>doystart</code>, <code>doyend</code>, <code>epoch</code>, <code>exitstatus</code>)</p>
<h1 id="parameters">Parameters</h1>
<dl>
<dt><code>filename</code> : input, character(*)</dt>
<dd>The ascii-formatted filename containing the spherical harmonic coefficients.
</dd>
<dt><code>cilm</code> : output, real*8, dimension (2, <code>lmax</code>+1, <code>lmax</code>+1)</dt>
<dd>The spherical harmonic coefficients contained in <code>filename</code>.
</dd>
<dt><code>lmax</code> : output, integer</dt>
<dd>The maximum spherical harmonic degree of <code>cilm</code>.
</dd>
<dt><code>gm</code> : output, real*8</dt>
<dd>The mass-gravitational constant.
</dd>
<dt><code>r0_pot</code> : output, real*8</dt>
<dd>The reference radius of the potential coefficients.
</dd>
<dt><code>error</code> : output, optional, real*8, dimension (2, <code>lmax</code>+1, <code>lmax</code>+1)</dt>
<dd>The errors corresponding to the spherical harmonic coefficients <code>cilm</code>.
</dd>
<dt><code>dot</code> : output, optional, real*8, dimension (2, <code>lmaxout</code>+1, <code>lmaxout</code>+1)</dt>
<dd>The time derivatives of the spherical harmonic coefficients. The dimension of this array can be smaller than <code>lmax+1</code>.
</dd>
<dt><code>doystart</code> : output, optional, real*8</dt>
<dd>The starting time of the solution.
</dd>
<dt><code>doyend</code> : output, optional, real*8</dt>
<dd>The ending time of the solution
</dd>
<dt><code>epoch</code> : output, optional, real*8</dt>
<dd>The epoch time for the time derivates.
</dd>
<dt><code>exitstatus</code> : output, optional, integer</dt>
<dd>If present, instead of executing a STOP when an error is encountered, the variable exitstatus will be returned describing the error. 0 = No errors; 1 = Improper dimensions of input array; 2 = Improper bounds for input variable; 3 = Error allocating memory; 4 = File IO error.
</dd>
</dl>
<h1 id="description">Description</h1>
<p><code>SHRead2</code> will read spherical harmonic coefficients from a CHAMP or GRACE-like ascii-formatted file into an array <code>cilm</code>. The errors and time derivatives associated with the coefficients will be read if the optional arrays <code>error</code> and <code>dot</code> are specified, respectively. The staring and ending date of the solution are specified by the optional parameters <code>doystart</code> and <code>doyend</code>, and the epoch of the time derivates is specified by the optional parameter <code>epoch</code>. The maximum spherical harmonic degree is read from the file, and the file does not need to be ordered by angular degree or order.</p>
<p>This routine does not read and output all parameters in the file. Records that are read (and at least partially output) include: <code>EARTH</code>, <code>GGM</code>, <code>SHM</code>, <code>GRCOF2</code>, <code>GRDOTA</code>, <code>CALSDV</code>, <code>gfc</code>, <code>gfct</code>, and <code>dot</code>. Comments specified by the record <code>CMMNT</code> will be print out to the screen, as will the record names that are not currently implemented.</p>
<p>Each line of the file starts with a character string describing what follows.</p>
<ul>
<li><code>EARTH</code> or <code>GGM</code>: <code>GM</code>, <code>R0_POT</code></li>
<li><code>SHM</code>: Maximum spherical harmonic degree of file.</li>
<li><code>GRCOF2</code>, <code>CALSDV</code>, or <code>gfc</code>: spherical harmonic coefficients, formatted as (<code>l</code>, <code>m</code>, <code>clm</code>, <code>slm</code>) or (<code>l</code>, <code>m</code>, <code>clm</code>, <code>slm</code>, <code>clm_error</code>, <code>slm_error</code>).</li>
</ul>
<h1 id="see-also">See also</h1>
<p><a href="shread.html">shread</a>, <a href="shreadjpl.html">shreadjpl</a></p>

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