0237"></a>00237 
<a name="l00238"></a>00238   <span class="comment">// return marginal probability of j-th tag id at i-th token</span>
<a name="l00239"></a>00239   <span class="keyword">virtual</span> <span class="keywordtype">double</span> prob(<span class="keywordtype">size_t</span> i, <span class="keywordtype">size_t</span> j) <span class="keyword">const</span> = 0;
<a name="l00240"></a>00240 
<a name="l00241"></a>00241   <span class="comment">// return marginal probability of output tag at i-th token</s