+
−<p>
+
−  The use of LTPDA objects requires some understanding of the nature of objects as implemented in MATLAB.
+
−</p>
+
−<p>
+
−  For full details of objects in MATLAB, refer to <a href="matlab:web(['jar:file:///' matlabroot '/help/techdoc/help.jar!/matlab_oop/ug_intropage.html'])">MATLAB Classes and Object-Oriented Programming</a>.
+
−  For convenience, the most important aspects in the context of LTPDA are reviewed below.
+
−</p>
+
−<p>
+
−  <ul>
+
−    <li>
+
−      <p><a href="objects_working.html#calling">Calling object methods</a></p>
+
−    </li>
+
−    <li>
+
−      <p><a href="objects_working.html#set">Setting object properties</a></p>
+
−    </li>
+
−    <li>
+
−      <p><a href="objects_working.html#copy">Copying objects</a></p>
+
−    </li>
+
−    <li><a href="objects_working.html#exploring">Exploring objects</a></li>
+
−  </ul>
+
−</p>
+
−
+
−<a name="calling" id= "calling"><h3 class="title">Calling object methods</h3></a>
+
−
+
−<p>
+
−  Each class in LTPDA has a set of methods (functions) which can operate/act on instances of the class (objects).
+
−  For example, the AO class has a method <tt>psd</tt> which can compute the Power Spectral Density estimate of a
+
−  time-series AO.
+
−</p>
+
−<p>
+
−  To see which methods a particular class has, use the <tt>methods</tt> command. For example,
+
−  <div class="fragment"><pre>
+
−      >> methods(<span class="string">'ao'</span>)
+
−  </pre></div>
+
−</p>
+
−<p>
+
−  To call a method on an object, <tt>obj.method</tt>, or, <tt>method(obj)</tt>. For example,
+
−  <div class="fragment"><pre>
+
−      >> b = a.psd
+
−  </pre></div>
+
−  or
+
−  <div class="fragment"><pre>
+
−      >> b = psd(a)
+
−  </pre></div>
+
−  Additional arguments can be passed to the method (a <tt>plist</tt>, for example), as follows:
+
−  <div class="fragment"><pre>
+
−      >> b = a.psd(pl)
+
−  </pre></div>
+
−  or
+
−  <div class="fragment"><pre>
+
−      >> b = psd(a, pl)
+
−  </pre></div>
+
−</p><br>
+
−<p>
+
−  In order to pass multiple objects to a method, you must use the form
+
−  <div class="fragment"><pre>
+
−      >> b = psd(a1, a2, pl)
+
−  </pre></div>
+
−</p><br>
+
−<p>
+
−  Some methods can behave as modifiers which means that the object which the method acts on is modified. To
+
−  modify an object, just give no output. If we start with a time-series AO then modify it with the <tt>psd</tt>
+
−  method,
+
−  <div class="fragment"><pre>
+
−      >> a = ao(1:100, randn(100,1), 10)
+
−      >> a
+
−       M:   running ao/display
+
−      ----------- ao 01: a -----------
+
−      
+
−             name:  None
+
−             data: (0,0.840375529753905) (0.1,-0.88803208232901) (0.2,0.100092833139322) (0.3,-0.544528929990548) (0.4,0.303520794649354) ...
+
−                   -------- tsdata 01 ------------
+
−              
+
−                       fs:  10
+
−                        x:  [100 1], double
+
−                        y:  [100 1], double
+
−                       dx:  [0 0], double
+
−                       dy:  [0 0], double
+
−                   xunits:  [s]
+
−                   yunits:  []
+
−                    nsecs:  10
+
−                       t0:  1970-01-01 00:00:01.000
+
−                   -------------------------------
+
−              
+
−             hist:  ao / ao / SId: fromVals ... -->$Id: ao .... S
+
−          mdlfile:  empty
+
−      description:  
+
−             UUID:  8cffab46-61f0-494a-af03-eb310aa76114
+
−      --------------------------------
+
−  </pre></div><br>
+
−  Then call the <tt>psd</tt> method:
+
−  <div class="fragment"><pre>
+
−      >> a.psd
+
−       M:   running ao/psd
+
−       M:   running ao/len
+
−       M:   running ao/len
+
−       M:   running ao/display
+
−      ----------- ao 01: PSD(a) -----------
+
− 
+
−             name:  PSD(a)
+
−             data: (0,0.117412356146407) (0.1,0.179893990497347) (0.2,0.173957816470448) (0.3,0.245076068355785) (0.4,0.213036543621994) ...
+
−                   ----------- fsdata 01 -----------
+
−              
+
−                       fs:  10
+
−                        x:  [51 1], double
+
−                        y:  [51 1], double
+
−                       dx:  [0 0], double
+
−                       dy:  [0 0], double
+
−                   xunits:  [Hz]
+
−                   yunits:  [Hz^(-1)]
+
−                       t0:  1970-01-01 00:00:01.000
+
−                     navs:  1
+
−                   ---------------------------------
+
−              
+
−             hist:  ao / psd / SId: psd.m,v 1.52 2009/09/05 05:57:32 mauro Exp S
+
−          mdlfile:  empty
+
−      description:  
+
−             UUID:  0d2395cd-22af-4645-a94c-69fa32c15982
+
−      -------------------------------------
+
−  </pre></div><br>
+
−  then the object <tt>a</tt> is converted to a frequency-series AO.
+
−</p><br>
+
−<p>
+
−  This modifier behaviour only works with certain methods, in particular, methods requiring more than one input object
+
−  will not behave as modifiers.
+
−</p><br>
+
−<a name="set" id= "set"><h3 class="title">Setting object properties</h3></a>
+
−<p>
+
−  All object properties must be set using the appropriate setter method. For example, to set the name of a IIR filter
+
−  object,
+
−  <div class="fragment"><pre>
+
−      >> ii = miir();
+
−      >> ii.setName(<span class="string">'My Filter'</span>);
+
−  </pre></div>
+
−</p>
+
−<p>
+
−  Reading the value of a property is achieved by:
+
−  <div class="fragment"><pre>
+
−      >> ii.name
+
−
+
−      ans =
+
−
+
−      My Filter
+
−  </pre></div>
+
−</p><br>
+
−
+
−<a name="copy" id= "copy"><h3 class="title">Copying objects</h3></a>
+
−<br>
+
−<p>
+
−  Since all objects in LTPDA are handle objects, creating copies of objects needs to be done differently than in standard
+
−  MATLAB. For example,
+
−  <div class="fragment"><pre>
+
−      >> a = ao();
+
−      >> b = a;
+
−  </pre></div>
+
−  in this case, the variable <tt>b</tt> is a copy of the handle <tt>a</tt>, not a copy of the object pointed too
+
−  by the handle <tt>a</tt>. To see how this behaves,
+
−  <div class="fragment"><pre>
+
−      >> a = ao();
+
−      >> b = a;
+
−      >> b.setName(<span class="string">'My Name'</span>);
+
−      >> a.name
+
−
+
−      ans =
+
−
+
−      My Name
+
−  </pre></div>
+
−</p>
+
−<p>
+
−  Copying the object can be achieved using the copy constructor:
+
−  <div class="fragment"><pre>
+
−      >> a = ao();
+
−      >> b = ao(a);
+
−      >> b.setName(<span class="string">'My Name'</span>);
+
−      >> a.name
+
−
+
−      ans =
+
−
+
−      none
+
−  </pre></div>
+
−  <p>In this case, the variable <tt>b</tt> points to a new distinct copy of the object pointed to by <tt>a</tt>.
+
−    </p>
+
−</p>
+
−  <p></p>
+
−<h3 class="title"><a name="exploring" id="calling2">Exploring objects</a></h3>
+
−  <p> A browsing tool is provided on purpose to enable LTPDA objects exploring.</p>
+
−  <p><a href="gui_explorer.html">See the LTPDA Objects Explorer GUI documentation.</a></p>