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<h1>matrictint
</h1>
<h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>function w=matrictint(S,XXi,T)</strong></div>
<h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="box"><strong>function w=matrictint(S,XXi,T) </strong></div>
<h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre class="comment">function w=matrictint(S,XXi,T)
S: usually sample cross product matrix of LS residuals
XXi: inv(X'X) matrix for rhs variables
T: number of observations
w: log of integrated posterior for SUR or RF VAR with det(Sigma)^(-(m+1)/2) Jeffreys-like prior
To get the log of the integral of the likelihood for a VAR with T observations,
k rhs variables in each equation, and m equations, set T=T-m-1 and subtract .5*m*(m+1)*log(2*pi).
We are integrating the exponential of -.5*T*m*log(2*pi)-.5*(T+m+1)*log(det(Sigma))-.5*trace(Sigma\S(beta)).</pre></div>
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<h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
This function calls:
<ul style="list-style-image:url(../matlabicon.gif)">
</ul>
This function is called by:
<ul style="list-style-image:url(../matlabicon.gif)">
<li><a href="mgnldnsty.html" class="code" title="function w=mgnldnsty(ydata,lags,xdata,breaks,lambda,mu,mnprior,vprior,train,flat)">mgnldnsty</a> function w=mgnldnsty(ydata,lags,xdata,breaks,lambda,mu,mnprior,vprior,train,flat)</li></ul>
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<h2><a name="_subfunctions"></a>SUBFUNCTIONS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<ul style="list-style-image:url(../matlabicon.gif)">
<li><a href="#_sub1" class="code">function lgg=ggammaln(m,ndf)</a></li></ul>
<h2><a name="_source"></a>SOURCE CODE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>
<div class="fragment"><pre>0001 <a name="_sub0" href="#_subfunctions" class="code">function w=matrictint(S,XXi,T)</a>
0002 <span class="comment">%function w=matrictint(S,XXi,T)</span>
0003 <span class="comment">% S: usually sample cross product matrix of LS residuals</span>
0004 <span class="comment">% XXi: inv(X'X) matrix for rhs variables</span>
0005 <span class="comment">% T: number of observations</span>
0006 <span class="comment">% w: log of integrated posterior for SUR or RF VAR with det(Sigma)^(-(m+1)/2) Jeffreys-like prior</span>
0007 <span class="comment">% To get the log of the integral of the likelihood for a VAR with T observations,</span>
0008 <span class="comment">% k rhs variables in each equation, and m equations, set T=T-m-1 and subtract .5*m*(m+1)*log(2*pi).</span>
0009 <span class="comment">% We are integrating the exponential of -.5*T*m*log(2*pi)-.5*(T+m+1)*log(det(Sigma))-.5*trace(Sigma\S(beta)).</span>
0010 k=size(XXi,1);
0011 m=size(S,1);
0012 [cx,p]=chol(XXi);
0013 [cs,q]=chol(S);
0014 <span class="comment">%cx=cschol(XXi);</span>
0015 <span class="comment">%cs=cschol(S);</span>
0016 <span class="keyword">if</span> any(diag(cx)&lt;100*eps)
0017 error(<span class="string">'singular XXi'</span>)
0018 <span class="keyword">end</span>
0019 <span class="keyword">if</span> any(diag(cs&lt;100*eps))
0020 error(<span class="string">'singular S'</span>)
0021 <span class="keyword">end</span>
0022 w=(-T+k+(m-1)/2)*m*.5*log(pi)-(T-k)*sum(log(diag(cs)))+m*sum(log(diag(cx)))+<a href="#_sub1" class="code" title="subfunction lgg=ggammaln(m,ndf)">ggammaln</a>(m,(T-k)/2);
0023
0024 <a name="_sub1" href="#_subfunctions" class="code">function lgg=ggammaln(m,ndf)</a>
0025 <span class="comment">%function gg=ggamma(m,ndf)</span>
0026 <span class="comment">% From 8.2.22 on p.427 of Box and Tiao, this is the log of generalized</span>
0027 <span class="comment">% gamma divided by gamma(.5)^(.5*m*(m-1))</span>
0028 <span class="keyword">if</span> ndf&lt;=(m-1)/2
0029 error(<span class="string">'too few df in ggammaln'</span>)
0030 <span class="keyword">else</span>
0031 <span class="comment">%lgg=.5*m*(m-1)*gammaln(.5); % normalizing factor not used in Wishart integral</span>
0032 garg=ndf+.5*(0:-1:1-m);
0033 lgg=sum(gammaln(garg));
0034 <span class="keyword">end</span>
0035</pre></div>
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