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71<h1>itpp::LDPC_Parity_Irregular Class Reference</h1><!-- doxytag: class="itpp::LDPC_Parity_Irregular" --><!-- doxytag: inherits="itpp::LDPC_Parity_Unstructured" -->Irregular LDPC code generator class. 
72<a href="#_details">More...</a>
73<p>
74<code>#include &lt;<a class="el" href="ldpc_8h-source.html">ldpc.h</a>&gt;</code>
75<p>
76
77<p>
78<a href="classitpp_1_1LDPC__Parity__Irregular-members.html">List of all members.</a><table border="0" cellpadding="0" cellspacing="0">
79<tr><td></td></tr>
80<tr><td colspan="2"><br><h2>Public Member Functions</h2></td></tr>
81<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="4c1ead5bc73b40163e533d54277fdeec"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::LDPC_Parity_Irregular" ref="4c1ead5bc73b40163e533d54277fdeec" args="()" -->
82&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html#4c1ead5bc73b40163e533d54277fdeec">LDPC_Parity_Irregular</a> ()</td></tr>
83
84<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Default constructor. <br></td></tr>
85<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="68e230fc50b54e2d8f2ebae6d483c243"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::LDPC_Parity_Irregular" ref="68e230fc50b54e2d8f2ebae6d483c243" args="(int Nvar, const vec &amp;var_deg, const vec &amp;chk_deg, const std::string &amp;method=&quot;rand&quot;, const ivec &amp;options=&quot;200 6&quot;)" -->
86&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html#68e230fc50b54e2d8f2ebae6d483c243">LDPC_Parity_Irregular</a> (int Nvar, const vec &amp;var_deg, const vec &amp;chk_deg, const std::string &amp;method=&quot;rand&quot;, const ivec &amp;options=&quot;200 6&quot;)</td></tr>
87
88<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Constructor that invokes <code><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html#c441e868691b1e6d634ee09db6228274" title="Generate an irregular LDPC code.">generate()</a></code> method. <br></td></tr>
89<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html#c441e868691b1e6d634ee09db6228274">generate</a> (int Nvar, const vec &amp;var_deg, const vec &amp;chk_deg, const std::string &amp;method=&quot;rand&quot;, const ivec &amp;options=&quot;200 6&quot;)</td></tr>
90
91<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Generate an irregular LDPC code.  <a href="#c441e868691b1e6d634ee09db6228274"></a><br></td></tr>
92<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="e8161a5209869b9623fde53cf30527c5"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::display_stats" ref="e8161a5209869b9623fde53cf30527c5" args="() const " -->
93void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html#e8161a5209869b9623fde53cf30527c5">display_stats</a> () const </td></tr>
94
95<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Display some information about the matrix. <br></td></tr>
96<tr><td class="memItemLeft" nowrap align="right" valign="top">int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Unstructured.html#32dc0098889fb7cbe925122a220ba504">cycle_removal_MGW</a> (int L)</td></tr>
97
98<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Remove cycles (loops) from unstructured parity check matrix.  <a href="#32dc0098889fb7cbe925122a220ba504"></a><br></td></tr>
99<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="f43eb94744828d0203ecef66f10ea252"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::initialize" ref="f43eb94744828d0203ecef66f10ea252" args="(int ncheck, int nvar)" -->
100void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#f43eb94744828d0203ecef66f10ea252">initialize</a> (int <a class="el" href="classitpp_1_1LDPC__Parity.html#82403ae65de864fdbe4fcdd4d83caff2">ncheck</a>, int <a class="el" href="classitpp_1_1LDPC__Parity.html#7e8697111c53562022e2f367593366c7">nvar</a>)</td></tr>
101
102<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Initialize an empty matrix of size ncheck x nvar. <br></td></tr>
103<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="5943f4ca9d8b00dca5fd85f603b4b1c0"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_H" ref="5943f4ca9d8b00dca5fd85f603b4b1c0" args="(bool transpose=false) const " -->
104<a class="el" href="classitpp_1_1Sparse__Mat.html">GF2mat_sparse</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#5943f4ca9d8b00dca5fd85f603b4b1c0">get_H</a> (bool transpose=false) const </td></tr>
105
106<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get the parity check matrix, optionally its transposed form. <br></td></tr>
107<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="b033b6ca4ab2b951cc503e05d6c9a61b"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_col" ref="b033b6ca4ab2b951cc503e05d6c9a61b" args="(int c) const " -->
108<a class="el" href="classitpp_1_1Sparse__Vec.html">Sparse_Vec</a>&lt; <a class="el" href="classitpp_1_1bin.html">bin</a> &gt;&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#b033b6ca4ab2b951cc503e05d6c9a61b">get_col</a> (int c) const </td></tr>
109
110<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get a specific column from the matrix. <br></td></tr>
111<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="2740d5f207c00bbcfcd610d9aa96527e"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_row" ref="2740d5f207c00bbcfcd610d9aa96527e" args="(int r) const " -->
112<a class="el" href="classitpp_1_1Sparse__Vec.html">Sparse_Vec</a>&lt; <a class="el" href="classitpp_1_1bin.html">bin</a> &gt;&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#2740d5f207c00bbcfcd610d9aa96527e">get_row</a> (int r) const </td></tr>
113
114<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get a specific row from the matrix. <br></td></tr>
115<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="7e63f3e0488b7c8b0402b7ca2b659f14"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_nvar" ref="7e63f3e0488b7c8b0402b7ca2b659f14" args="() const " -->
116int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#7e63f3e0488b7c8b0402b7ca2b659f14">get_nvar</a> () const </td></tr>
117
118<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get the number of variable nodes (number of columns). <br></td></tr>
119<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="187f147ffeca6c2744235cbf27ce22f3"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_ncheck" ref="187f147ffeca6c2744235cbf27ce22f3" args="() const " -->
120int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#187f147ffeca6c2744235cbf27ce22f3">get_ncheck</a> () const </td></tr>
121
122<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get the number of check nodes (number of rows). <br></td></tr>
123<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="9847b116e69bd7edcaef3704d5b997f8"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::set" ref="9847b116e69bd7edcaef3704d5b997f8" args="(int i, int j, bin value)" -->
124void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#9847b116e69bd7edcaef3704d5b997f8">set</a> (int i, int j, <a class="el" href="classitpp_1_1bin.html">bin</a> value)</td></tr>
125
126<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Set element (i,j) of the parity check matrix to value. <br></td></tr>
127<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="c70ddfe8b703d1eb4d22a19f10f0e8c9"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get" ref="c70ddfe8b703d1eb4d22a19f10f0e8c9" args="(int i, int j) const " -->
128<a class="el" href="classitpp_1_1bin.html">bin</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#c70ddfe8b703d1eb4d22a19f10f0e8c9">get</a> (int i, int j) const </td></tr>
129
130<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get element (i,j) of the parity check matrix. <br></td></tr>
131<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="2b2923d5f0ffafe41a427326f34c8784"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::operator()" ref="2b2923d5f0ffafe41a427326f34c8784" args="(int i, int j) const " -->
132<a class="el" href="classitpp_1_1bin.html">bin</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#2b2923d5f0ffafe41a427326f34c8784">operator()</a> (int i, int j) const </td></tr>
133
134<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get element (i,j) of the parity check matrix. <br></td></tr>
135<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="35bd2abd71714312866811d3255d68c8"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::get_rate" ref="35bd2abd71714312866811d3255d68c8" args="() const " -->
136double&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#35bd2abd71714312866811d3255d68c8">get_rate</a> () const </td></tr>
137
138<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Get the code rate. <br></td></tr>
139<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="4e1fd0b2147b5d486e24538615e1fbf4"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::import_alist" ref="4e1fd0b2147b5d486e24538615e1fbf4" args="(const GF2mat_sparse_alist &amp;H_alist)" -->
140void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#4e1fd0b2147b5d486e24538615e1fbf4">import_alist</a> (const <a class="el" href="classitpp_1_1GF2mat__sparse__alist.html">GF2mat_sparse_alist</a> &amp;H_alist)</td></tr>
141
142<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Import matrix from <code><a class="el" href="classitpp_1_1GF2mat__sparse__alist.html" title="Parameterized &quot;alist&quot; representation of sparse GF(2) matrix.">GF2mat_sparse_alist</a></code> format. <br></td></tr>
143<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="811f5be45f91edf337d1ec48a125f2a7"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::export_alist" ref="811f5be45f91edf337d1ec48a125f2a7" args="() const " -->
144<a class="el" href="classitpp_1_1GF2mat__sparse__alist.html">GF2mat_sparse_alist</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#811f5be45f91edf337d1ec48a125f2a7">export_alist</a> () const </td></tr>
145
146<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Export matrix to <code><a class="el" href="classitpp_1_1GF2mat__sparse__alist.html" title="Parameterized &quot;alist&quot; representation of sparse GF(2) matrix.">GF2mat_sparse_alist</a></code> format. <br></td></tr>
147<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="0a8956859defe1d19e79441b9da281b3"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::load_alist" ref="0a8956859defe1d19e79441b9da281b3" args="(const std::string &amp;alist_file)" -->
148void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#0a8956859defe1d19e79441b9da281b3">load_alist</a> (const std::string &amp;alist_file)</td></tr>
149
150<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Load matrix from <code>alist_file</code> text file in alist format. <br></td></tr>
151<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="f653d919cb8c3d08e2d700809155999a"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::save_alist" ref="f653d919cb8c3d08e2d700809155999a" args="(const std::string &amp;alist_file) const " -->
152void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#f653d919cb8c3d08e2d700809155999a">save_alist</a> (const std::string &amp;alist_file) const </td></tr>
153
154<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Save matrix to <code>alist_file</code> text file in alist format. <br></td></tr>
155<tr><td colspan="2"><br><h2>Protected Member Functions</h2></td></tr>
156<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="65d83d2aa65aa098b10341da4adba70e"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::generate_random_H" ref="65d83d2aa65aa098b10341da4adba70e" args="(const ivec &amp;C, const ivec &amp;R, const ivec &amp;cycopt)" -->
157void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Unstructured.html#65d83d2aa65aa098b10341da4adba70e">generate_random_H</a> (const ivec &amp;C, const ivec &amp;R, const ivec &amp;cycopt)</td></tr>
158
159<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Generate a random parity check matrix. <br></td></tr>
160<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity__Unstructured.html#143f0a5c1def918e21fe30bcd5af176c">compute_CR</a> (const vec &amp;var_deg, const vec &amp;chk_deg, const int Nvar, ivec &amp;C, ivec &amp;R)</td></tr>
161
162<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Compute target number of columns (C) and rows (R) with a specific number of ones.  <a href="#143f0a5c1def918e21fe30bcd5af176c"></a><br></td></tr>
163<tr><td class="memItemLeft" nowrap align="right" valign="top">int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#2849e24a0089c0b62105b8bbc4072d0e">check_for_cycles</a> (int L) const </td></tr>
164
165<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Check for cycles of length L.  <a href="#2849e24a0089c0b62105b8bbc4072d0e"></a><br></td></tr>
166<tr><td class="memItemLeft" nowrap align="right" valign="top">int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#d30f8e78f5e951be44660d0750b70cb6">check_connectivity</a> (int from_m, int from_n, int to_m, int to_n, int g, int L) const </td></tr>
167
168<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Check for connectivity between nodes.  <a href="#d30f8e78f5e951be44660d0750b70cb6"></a><br></td></tr>
169<tr><td colspan="2"><br><h2>Protected Attributes</h2></td></tr>
170<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="74998d26a4dd6057f3a8be6ac4f2c5c1"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::init_flag" ref="74998d26a4dd6057f3a8be6ac4f2c5c1" args="" -->
171bool&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#74998d26a4dd6057f3a8be6ac4f2c5c1">init_flag</a></td></tr>
172
173<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Flag that indicates proper initialization. <br></td></tr>
174<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="f51c1108ec92883ef46a55083e7263ec"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::H" ref="f51c1108ec92883ef46a55083e7263ec" args="" -->
175<a class="el" href="classitpp_1_1Sparse__Mat.html">GF2mat_sparse</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#f51c1108ec92883ef46a55083e7263ec">H</a></td></tr>
176
177<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">The parity check matrix. <br></td></tr>
178<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="0355499a802f0aeb3cb1b5f720fdc924"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::Ht" ref="0355499a802f0aeb3cb1b5f720fdc924" args="" -->
179<a class="el" href="classitpp_1_1Sparse__Mat.html">GF2mat_sparse</a>&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#0355499a802f0aeb3cb1b5f720fdc924">Ht</a></td></tr>
180
181<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">The transposed parity check matrix. <br></td></tr>
182<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="7e8697111c53562022e2f367593366c7"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::nvar" ref="7e8697111c53562022e2f367593366c7" args="" -->
183int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#7e8697111c53562022e2f367593366c7">nvar</a></td></tr>
184
185<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Number of variable nodes. <br></td></tr>
186<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="82403ae65de864fdbe4fcdd4d83caff2"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::ncheck" ref="82403ae65de864fdbe4fcdd4d83caff2" args="" -->
187int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#82403ae65de864fdbe4fcdd4d83caff2">ncheck</a></td></tr>
188
189<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Number of check nodes. <br></td></tr>
190<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="d57f9e546f3a50b1dd84a587e36562fc"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::sumX1" ref="d57f9e546f3a50b1dd84a587e36562fc" args="" -->
191ivec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#d57f9e546f3a50b1dd84a587e36562fc">sumX1</a></td></tr>
192
193<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Actual number of ones in each column. <br></td></tr>
194<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="4c4347f86ad11c0f303f52a5134e851c"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::sumX2" ref="4c4347f86ad11c0f303f52a5134e851c" args="" -->
195ivec&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#4c4347f86ad11c0f303f52a5134e851c">sumX2</a></td></tr>
196
197<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Actual number of ones in each row. <br></td></tr>
198<tr><td colspan="2"><br><h2>Static Protected Attributes</h2></td></tr>
199<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="anchor" name="0114010da4b27165cfc748f23d15edeb"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::Nmax" ref="0114010da4b27165cfc748f23d15edeb" args="" -->
200static const int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="classitpp_1_1LDPC__Parity.html#0114010da4b27165cfc748f23d15edeb">Nmax</a> = 200</td></tr>
201
202<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Maximum node degree class can handle. <br></td></tr>
203</table>
204<hr><a name="_details"></a><h2>Detailed Description</h2>
205Irregular LDPC code generator class.
206<p>
207<dl class="author" compact><dt><b>Author:</b></dt><dd>Erik G. Larsson, Mattias Andersson and Adam Piatyszek </dd></dl>
208<hr><h2>Member Function Documentation</h2>
209<a class="anchor" name="d30f8e78f5e951be44660d0750b70cb6"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::check_connectivity" ref="d30f8e78f5e951be44660d0750b70cb6" args="(int from_m, int from_n, int to_m, int to_n, int g, int L) const " -->
210<div class="memitem">
211<div class="memproto">
212      <table class="memname">
213        <tr>
214          <td class="memname">int itpp::LDPC_Parity::check_connectivity           </td>
215          <td>(</td>
216          <td class="paramtype">int&nbsp;</td>
217          <td class="paramname"> <em>from_m</em>, </td>
218        </tr>
219        <tr>
220          <td class="paramkey"></td>
221          <td></td>
222          <td class="paramtype">int&nbsp;</td>
223          <td class="paramname"> <em>from_n</em>, </td>
224        </tr>
225        <tr>
226          <td class="paramkey"></td>
227          <td></td>
228          <td class="paramtype">int&nbsp;</td>
229          <td class="paramname"> <em>to_m</em>, </td>
230        </tr>
231        <tr>
232          <td class="paramkey"></td>
233          <td></td>
234          <td class="paramtype">int&nbsp;</td>
235          <td class="paramname"> <em>to_n</em>, </td>
236        </tr>
237        <tr>
238          <td class="paramkey"></td>
239          <td></td>
240          <td class="paramtype">int&nbsp;</td>
241          <td class="paramname"> <em>g</em>, </td>
242        </tr>
243        <tr>
244          <td class="paramkey"></td>
245          <td></td>
246          <td class="paramtype">int&nbsp;</td>
247          <td class="paramname"> <em>L</em></td><td>&nbsp;</td>
248        </tr>
249        <tr>
250          <td></td>
251          <td>)</td>
252          <td></td><td></td><td> const<code> [protected, inherited]</code></td>
253        </tr>
254      </table>
255</div>
256<div class="memdoc">
257
258<p>
259Check for connectivity between nodes.
260<p>
261This function examines whether the point (to_m, to_n) in the matrix can be reached from the point (from_m, from_n) using at most L steps. A recursive search is used.<p>
262The function can be used to search for cycles in the matrix. To search for a cycle of length L, set from_m=to_m and from_n=to_n, and godir=0.<p>
263<dl compact><dt><b>Parameters:</b></dt><dd>
264  <table border="0" cellspacing="2" cellpadding="0">
265    <tr><td valign="top"></td><td valign="top"><em>from_m</em>&nbsp;</td><td>starting coordinate, row number </td></tr>
266    <tr><td valign="top"></td><td valign="top"><em>to_m</em>&nbsp;</td><td>goal coordinate, row number </td></tr>
267    <tr><td valign="top"></td><td valign="top"><em>from_n</em>&nbsp;</td><td>starting coordinate, column number </td></tr>
268    <tr><td valign="top"></td><td valign="top"><em>to_n</em>&nbsp;</td><td>goal coordinate, row number </td></tr>
269    <tr><td valign="top"></td><td valign="top"><em>g</em>&nbsp;</td><td>direction: 1=start going vertically, 2=start going horizontally </td></tr>
270    <tr><td valign="top"></td><td valign="top"><em>L</em>&nbsp;</td><td>number of permitted steps</td></tr>
271  </table>
272</dl>
273<dl class="return" compact><dt><b>Returns:</b></dt><dd><ul>
274<li>-1 or -3 : destination unreachable</li><li>-2 : meaningless search (started in a "0" point),</li><li>-4 : meaningless search</li><li>&gt;=0 : destination reached with certain number of steps left</li></ul>
275</dd></dl>
276<dl class="note" compact><dt><b>Note:</b></dt><dd>This function can be very slow depending on the nature of the matrix.</dd></dl>
277Note that smaller cycles may appear as longer cycles when using this method. More specifically, suppose the method is run with a given L and there are cycles in the neighborhood of (from_m,from_n) of length L-2 or less, but which do not contain (from_m,from_n). These shorter cycles may then also be reported as a cycle of length L. For example, if one of the immediate neighbors of (from_m,from_n) is part of a cycle of length 4 this method will report that (from_m,from_n) is part of a cycle of length 6, if run with L=6. However, if it is known that there are no cycles of length L-2 or smaller, and check_connectivity(from_m,from_n,from_m,from_n,0,L) returns a non-negative value, then one will know with certainty that the point (from_m,from_n) is part of a cycle of length L. (This behavior is inherent to the simple recursive search used.)
278<p>References <a class="el" href="ldpc_8h-source.html#l00108">itpp::LDPC_Parity::get_col()</a>, <a class="el" href="svec_8h-source.html#l00789">itpp::Sparse_Vec&lt; T &gt;::get_nz_indices()</a>, <a class="el" href="ldpc_8h-source.html#l00111">itpp::LDPC_Parity::get_row()</a>, <a class="el" href="ldpc_8h-source.html#l00169">itpp::LDPC_Parity::init_flag</a>, <a class="el" href="itassert_8h-source.html#l00094">it_assert</a>, and <a class="el" href="matfunc_8h-source.html#l00051">itpp::length()</a>.</p>
279
280<p>Referenced by <a class="el" href="ldpc_8cpp-source.html#l00249">itpp::LDPC_Parity::check_for_cycles()</a>, and <a class="el" href="ldpc_8cpp-source.html#l00462">itpp::LDPC_Parity_Unstructured::generate_random_H()</a>.</p>
281
282</div>
283</div><p>
284<a class="anchor" name="2849e24a0089c0b62105b8bbc4072d0e"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::check_for_cycles" ref="2849e24a0089c0b62105b8bbc4072d0e" args="(int L) const " -->
285<div class="memitem">
286<div class="memproto">
287      <table class="memname">
288        <tr>
289          <td class="memname">int itpp::LDPC_Parity::check_for_cycles           </td>
290          <td>(</td>
291          <td class="paramtype">int&nbsp;</td>
292          <td class="paramname"> <em>L</em>          </td>
293          <td>&nbsp;)&nbsp;</td>
294          <td> const<code> [protected, inherited]</code></td>
295        </tr>
296      </table>
297</div>
298<div class="memdoc">
299
300<p>
301Check for cycles of length L.
302<p>
303This function implements a recursive routine to find loops. The function is mainly a tool for testing and debugging more sophisticated functions for graph manipulation.<p>
304<dl compact><dt><b>Parameters:</b></dt><dd>
305  <table border="0" cellspacing="2" cellpadding="0">
306    <tr><td valign="top"></td><td valign="top"><em>L</em>&nbsp;</td><td>length of cycles to look for</td></tr>
307  </table>
308</dl>
309<dl class="return" compact><dt><b>Returns:</b></dt><dd>The function returns the number of cycles found of length L or shorter. Cycles may be counted multiple times.</dd></dl>
310<dl class="note" compact><dt><b>Note:</b></dt><dd>This function can be very slow for large matrices. It is mainly intended as a debugging aid. </dd></dl>
311
312<p>References <a class="el" href="ldpc_8cpp-source.html#l00192">itpp::LDPC_Parity::check_connectivity()</a>, <a class="el" href="ldpc_8h-source.html#l00108">itpp::LDPC_Parity::get_col()</a>, <a class="el" href="svec_8h-source.html#l00789">itpp::Sparse_Vec&lt; T &gt;::get_nz_indices()</a>, <a class="el" href="ldpc_8h-source.html#l00169">itpp::LDPC_Parity::init_flag</a>, <a class="el" href="itassert_8h-source.html#l00094">it_assert</a>, <a class="el" href="matfunc_8h-source.html#l00051">itpp::length()</a>, and <a class="el" href="ldpc_8h-source.html#l00177">itpp::LDPC_Parity::nvar</a>.</p>
313
314</div>
315</div><p>
316<a class="anchor" name="143f0a5c1def918e21fe30bcd5af176c"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::compute_CR" ref="143f0a5c1def918e21fe30bcd5af176c" args="(const vec &amp;var_deg, const vec &amp;chk_deg, const int Nvar, ivec &amp;C, ivec &amp;R)" -->
317<div class="memitem">
318<div class="memproto">
319      <table class="memname">
320        <tr>
321          <td class="memname">void itpp::LDPC_Parity_Unstructured::compute_CR           </td>
322          <td>(</td>
323          <td class="paramtype">const vec &amp;&nbsp;</td>
324          <td class="paramname"> <em>var_deg</em>, </td>
325        </tr>
326        <tr>
327          <td class="paramkey"></td>
328          <td></td>
329          <td class="paramtype">const vec &amp;&nbsp;</td>
330          <td class="paramname"> <em>chk_deg</em>, </td>
331        </tr>
332        <tr>
333          <td class="paramkey"></td>
334          <td></td>
335          <td class="paramtype">const int&nbsp;</td>
336          <td class="paramname"> <em>Nvar</em>, </td>
337        </tr>
338        <tr>
339          <td class="paramkey"></td>
340          <td></td>
341          <td class="paramtype">ivec &amp;&nbsp;</td>
342          <td class="paramname"> <em>C</em>, </td>
343        </tr>
344        <tr>
345          <td class="paramkey"></td>
346          <td></td>
347          <td class="paramtype">ivec &amp;&nbsp;</td>
348          <td class="paramname"> <em>R</em></td><td>&nbsp;</td>
349        </tr>
350        <tr>
351          <td></td>
352          <td>)</td>
353          <td></td><td></td><td><code> [protected, inherited]</code></td>
354        </tr>
355      </table>
356</div>
357<div class="memdoc">
358
359<p>
360Compute target number of columns (C) and rows (R) with a specific number of ones.
361<p>
362<dl compact><dt><b>Parameters:</b></dt><dd>
363  <table border="0" cellspacing="2" cellpadding="0">
364    <tr><td valign="top"></td><td valign="top"><em>var_deg</em>&nbsp;</td><td>vector of variable degree distributions, from an edge perspective </td></tr>
365    <tr><td valign="top"></td><td valign="top"><em>chk_deg</em>&nbsp;</td><td>vector of check degree distributions, from an edge perspective </td></tr>
366    <tr><td valign="top"></td><td valign="top"><em>Nvar</em>&nbsp;</td><td>number of variable nodes </td></tr>
367    <tr><td valign="top"></td><td valign="top"><em>C</em>&nbsp;</td><td>number of columns with a specific number of ones </td></tr>
368    <tr><td valign="top"></td><td valign="top"><em>R</em>&nbsp;</td><td>number of rows with a specific number of ones</td></tr>
369  </table>
370</dl>
371The result is passed by reference and saved in C and R.
372<p>References <a class="el" href="specmat_8cpp-source.html#l00039">itpp::find()</a>, <a class="el" href="itassert_8h-source.html#l00163">it_info_debug</a>, <a class="el" href="matfunc_8h-source.html#l00051">itpp::length()</a>, <a class="el" href="specmat_8cpp-source.html#l00114">itpp::linspace()</a>, <a class="el" href="tcp_8h-source.html#l00117">itpp::max()</a>, <a class="el" href="ldpc_8h-source.html#l00171">itpp::LDPC_Parity::Nmax</a>, <a class="el" href="converters_8h-source.html#l00327">itpp::round()</a>, <a class="el" href="matfunc_8h-source.html#l00077">itpp::sum()</a>, <a class="el" href="group__convertfunc.html#ga2c82af9774f45c3554fb03a06f3e28d">itpp::to_ivec()</a>, <a class="el" href="fix__functions_8cpp-source.html#l00036">itpp::to_vec()</a>, and <a class="el" href="group__specmat.html#g9df9aa3553b6a5c07924954b85466cec">itpp::zeros_i()</a>.</p>
373
374<p>Referenced by <a class="el" href="ldpc_8cpp-source.html#l00703">generate()</a>, and <a class="el" href="ldpc_8cpp-source.html#l00667">itpp::LDPC_Parity_Regular::generate()</a>.</p>
375
376</div>
377</div><p>
378<a class="anchor" name="32dc0098889fb7cbe925122a220ba504"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::cycle_removal_MGW" ref="32dc0098889fb7cbe925122a220ba504" args="(int L)" -->
379<div class="memitem">
380<div class="memproto">
381      <table class="memname">
382        <tr>
383          <td class="memname">int itpp::LDPC_Parity_Unstructured::cycle_removal_MGW           </td>
384          <td>(</td>
385          <td class="paramtype">int&nbsp;</td>
386          <td class="paramname"> <em>L</em>          </td>
387          <td>&nbsp;)&nbsp;</td>
388          <td><code> [inherited]</code></td>
389        </tr>
390      </table>
391</div>
392<div class="memdoc">
393
394<p>
395Remove cycles (loops) from unstructured parity check matrix.
396<p>
397This function implements the cycle removal algorithm presented by McGowan and Williamson at the IT workshop 2003. The maximum girth of the graph that will be attempted is L. The algorithm is bound to remove all loops of length L, insofar this is possible. I.e., it does not terminate until it is impossible to remove more cycles by swapping two edges.<p>
398<dl compact><dt><b>Parameters:</b></dt><dd>
399  <table border="0" cellspacing="2" cellpadding="0">
400    <tr><td valign="top"></td><td valign="top"><em>L</em>&nbsp;</td><td>Target girth. For example, L=6 attempts to removes all 4-cycles. </td></tr>
401  </table>
402</dl>
403<dl class="return" compact><dt><b>Returns:</b></dt><dd>The girth of the graph, i.e. the length of the shortest cycle. For example, a return value of 6 means that there are no 4-cycles.</dd></dl>
404<dl class="note" compact><dt><b>Note:</b></dt><dd>This algorithm can take a long time to run for large L or large graphs. </dd></dl>
405
406<p>References <a class="el" href="group__convertfunc.html#gb5745fd45c164c8d1e062359d0bf2783">itpp::floor_i()</a>, <a class="el" href="ldpc_8h-source.html#l00108">itpp::LDPC_Parity::get_col()</a>, <a class="el" href="svec_8h-source.html#l00239">itpp::Sparse_Vec&lt; T &gt;::get_nz_index()</a>, <a class="el" href="ldpc_8h-source.html#l00169">itpp::LDPC_Parity::init_flag</a>, <a class="el" href="itassert_8h-source.html#l00094">it_assert</a>, <a class="el" href="itassert_8h-source.html#l00107">it_assert_debug</a>, <a class="el" href="itassert_8h-source.html#l00163">it_info_debug</a>, <a class="el" href="matfunc_8h-source.html#l00051">itpp::length()</a>, <a class="el" href="ldpc_8h-source.html#l00179">itpp::LDPC_Parity::ncheck</a>, <a class="el" href="svec_8h-source.html#l00151">itpp::Sparse_Vec&lt; T &gt;::nnz()</a>, <a class="el" href="ldpc_8h-source.html#l00177">itpp::LDPC_Parity::nvar</a>, <a class="el" href="random_8h-source.html#l00615">itpp::randi()</a>, <a class="el" href="random_8h-source.html#l00608">itpp::randu()</a>, and <a class="el" href="array_8h-source.html#l00257">itpp::Array&lt; T &gt;::set_size()</a>.</p>
407
408</div>
409</div><p>
410<a class="anchor" name="c441e868691b1e6d634ee09db6228274"></a><!-- doxytag: member="itpp::LDPC_Parity_Irregular::generate" ref="c441e868691b1e6d634ee09db6228274" args="(int Nvar, const vec &amp;var_deg, const vec &amp;chk_deg, const std::string &amp;method=&quot;rand&quot;, const ivec &amp;options=&quot;200 6&quot;)" -->
411<div class="memitem">
412<div class="memproto">
413      <table class="memname">
414        <tr>
415          <td class="memname">void itpp::LDPC_Parity_Irregular::generate           </td>
416          <td>(</td>
417          <td class="paramtype">int&nbsp;</td>
418          <td class="paramname"> <em>Nvar</em>, </td>
419        </tr>
420        <tr>
421          <td class="paramkey"></td>
422          <td></td>
423          <td class="paramtype">const vec &amp;&nbsp;</td>
424          <td class="paramname"> <em>var_deg</em>, </td>
425        </tr>
426        <tr>
427          <td class="paramkey"></td>
428          <td></td>
429          <td class="paramtype">const vec &amp;&nbsp;</td>
430          <td class="paramname"> <em>chk_deg</em>, </td>
431        </tr>
432        <tr>
433          <td class="paramkey"></td>
434          <td></td>
435          <td class="paramtype">const std::string &amp;&nbsp;</td>
436          <td class="paramname"> <em>method</em> = <code>&quot;rand&quot;</code>, </td>
437        </tr>
438        <tr>
439          <td class="paramkey"></td>
440          <td></td>
441          <td class="paramtype">const ivec &amp;&nbsp;</td>
442          <td class="paramname"> <em>options</em> = <code>&quot;200&nbsp;6&quot;</code></td><td>&nbsp;</td>
443        </tr>
444        <tr>
445          <td></td>
446          <td>)</td>
447          <td></td><td></td><td></td>
448        </tr>
449      </table>
450</div>
451<div class="memdoc">
452
453<p>
454Generate an irregular LDPC code.
455<p>
456<dl compact><dt><b>Parameters:</b></dt><dd>
457  <table border="0" cellspacing="2" cellpadding="0">
458    <tr><td valign="top"></td><td valign="top"><em>Nvar</em>&nbsp;</td><td>number of variable nodes </td></tr>
459    <tr><td valign="top"></td><td valign="top"><em>var_deg</em>&nbsp;</td><td>vector of variable degree distributions, from an edge perspective </td></tr>
460    <tr><td valign="top"></td><td valign="top"><em>chk_deg</em>&nbsp;</td><td>vector of check degree distributions, from an edge perspective </td></tr>
461    <tr><td valign="top"></td><td valign="top"><em>method</em>&nbsp;</td><td>currently the only provided method is "rand" (see below) </td></tr>
462    <tr><td valign="top"></td><td valign="top"><em>options</em>&nbsp;</td><td>Determines the level of matrix optimization.</td></tr>
463  </table>
464</dl>
465The "rand" method generates a fully unstructured random matrix. Some stochastic optimization is performed to avoid cycles. This optimization is controlled via the parameter <code>options</code>. In particular, the girth for the variable-node-degree-2 part of the graph can be controlled via the parameter options(0). The girth for the rest of the nodes can be controlled via the parameter options(1). The recommended value for options is "200 6" for graphs of small size, and "100 4" for large graphs. The value "0 0" means no optimization. Double edges are always avoided.<p>
466<dl class="note" compact><dt><b>Note:</b></dt><dd>The "rand" method for graph construction provided in this function is not intended to provide the best possible error performance, but it is a simple, basic, fast tool that can easily be used to build relatively good irregular graphs. Better results in terms of performance and error-floor can be achieved by using other performance measures for the graph than cycle length (for irregular codes, the so-called ACE measure for example). Additionally, the "rand" method builds the graph edge by edge, with no possibility of removing an edge once it has been placed. Better results may be achieved by building the graphs by placing pairs or n-tuples of edges at time, for example, column by column.<p>
467Alternative (user-defined) methods for code generation can be implemented by inheriting <code><a class="el" href="classitpp_1_1LDPC__Parity__Irregular.html" title="Irregular LDPC code generator class.">LDPC_Parity_Irregular</a></code>. </dd></dl>
468
469<p>References <a class="el" href="ldpc_8cpp-source.html#l00598">itpp::LDPC_Parity_Unstructured::compute_CR()</a>, <a class="el" href="ldpc_8cpp-source.html#l00462">itpp::LDPC_Parity_Unstructured::generate_random_H()</a>, and <a class="el" href="itassert_8h-source.html#l00126">it_error</a>.</p>
470
471<p>Referenced by <a class="el" href="ldpc_8cpp-source.html#l00694">LDPC_Parity_Irregular()</a>.</p>
472
473</div>
474</div><p>
475<hr>The documentation for this class was generated from the following files:<ul>
476<li><a class="el" href="ldpc_8h-source.html">ldpc.h</a><li><a class="el" href="ldpc_8cpp.html">ldpc.cpp</a></ul>
477</div>
478<hr size="1"><address style="text-align: right;"><small>Generated on Tue Jun 2 10:02:19 2009 for mixpp by&nbsp;
479<a href="http://www.doxygen.org/index.html">
480<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.8 </small></address>
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