ex12.php

一个用来实现偏微分方程中网格的计算库

<pre>
              std::vector&lt;Number&gt; node_data;
              node_data.resize(2);
        
</pre>
</div>
<div class = "comment">
Use a sin curve in z-direction and a linear
increase in x-direction
</div>

<div class ="fragment">
<pre>
              const Point& p = **node_it;
        	
              const Real z_normalized = (p(2)-z_min)/(z_max-z_min);
              const Real x_normalized = (p(0)-x_min)/(x_max-x_min);
        
              node_data[0] = sin(2*libMesh::pi*z_normalized);
              node_data[1] = x_normalized;
              
</pre>
</div>
<div class = "comment">
Insert the current data together with a pointer to
the current node in the map.
</div>

<div class ="fragment">
<pre>
              art_data.insert (std::make_pair(*node_it,node_data));
            }
        }
</pre>
</div>

<a name="nocomments"></a> 
<br><br><br> <h1> The program without comments: </h1> 
<pre> 
  
  #include &lt;math.h&gt;
  
  #include <B><FONT COLOR="#BC8F8F">&quot;libmesh.h&quot;</FONT></B>
  
  #include <B><FONT COLOR="#BC8F8F">&quot;mesh.h&quot;</FONT></B>
  #include <B><FONT COLOR="#BC8F8F">&quot;mesh_tools.h&quot;</FONT></B>
  #include <B><FONT COLOR="#BC8F8F">&quot;mesh_data.h&quot;</FONT></B>
  #include <B><FONT COLOR="#BC8F8F">&quot;unv_io.h&quot;</FONT></B>
  #include <B><FONT COLOR="#BC8F8F">&quot;gmv_io.h&quot;</FONT></B>
  
  #include <B><FONT COLOR="#BC8F8F">&quot;node.h&quot;</FONT></B>
  
  <B><FONT COLOR="#228B22">void</FONT></B> create_artificial_data (<B><FONT COLOR="#228B22">const</FONT></B> Mesh&amp; mesh,
  			     <B><FONT COLOR="#5F9EA0">std</FONT></B>::map&lt;<B><FONT COLOR="#228B22">const</FONT></B> Node*, std::vector&lt;Number&gt; &gt;&amp; art_data);
  
  <B><FONT COLOR="#228B22">int</FONT></B> main (<B><FONT COLOR="#228B22">int</FONT></B> argc, <B><FONT COLOR="#228B22">char</FONT></B>** argv)
  {
    <B><FONT COLOR="#5F9EA0">libMesh</FONT></B>::init (argc, argv);
  
    {    
      <B><FONT COLOR="#A020F0">if</FONT></B> (argc &lt; 4)
        {
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::cerr &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Usage: &quot;</FONT></B> &lt;&lt; argv[0] &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot; -d &lt;dim&gt; in_mesh.unv&quot;</FONT></B>
  		  &lt;&lt; std::endl;
  	
  	error();
        }
  
      <B><FONT COLOR="#228B22">const</FONT></B> <B><FONT COLOR="#228B22">unsigned</FONT></B> <B><FONT COLOR="#228B22">int</FONT></B> dim = std::atoi(argv[2]);
      
      <B><FONT COLOR="#228B22">const</FONT></B> std::string mesh_file = argv[3];
  
      <B><FONT COLOR="#A020F0">if</FONT></B> (mesh_file.rfind(<B><FONT COLOR="#BC8F8F">&quot;.unv&quot;</FONT></B>) &gt;= mesh_file.size())
        {
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::cerr &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;ERROR:  This example works only properly with a Universal mesh file!&quot;</FONT></B>
  		  &lt;&lt; std::endl;
  	
  	error();
        }
    
      {
        assert (dim == 3);
        Mesh mesh(dim);
        MeshData mesh_data(mesh);
        
        mesh_data.activate();
  
        mesh.read (mesh_file, &amp;mesh_data);
        
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Finished reading the mesh.  MeshData is active but empty:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;---------------------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl;
        
        mesh.print_info();
        mesh_data.print_info();
      
        {
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::map&lt;<B><FONT COLOR="#228B22">const</FONT></B> Node*, std::vector&lt;Number&gt; &gt; artificial_data;
  	
  	create_artificial_data (mesh, artificial_data);
  	
  	mesh_data.insert_node_data(artificial_data);
  
        }
        
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;After inserting artificial data into the MeshData:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;--------------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl;
        
        mesh_data.print_info();
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::string first_out_data=<B><FONT COLOR="#BC8F8F">&quot;data_first_out_with_default_header.unv&quot;</FONT></B>;
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing MeshData to: &quot;</FONT></B> &lt;&lt; first_out_data &lt;&lt; std::endl;
        mesh_data.write(first_out_data);
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Attach our own MeshDataUnvHeader to the MeshData:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;-------------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot; (note the warning: the number of values per node in&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;  my_header is not correct)&quot;</FONT></B> &lt;&lt; std::endl &lt;&lt; std::endl;
        MeshDataUnvHeader my_header;
  
        my_header.dataset_label = 3;
  
        my_header.id_lines_1_to_5[0] = <B><FONT COLOR="#BC8F8F">&quot;Artificial data&quot;</FONT></B>;
        my_header.id_lines_1_to_5[1] = <B><FONT COLOR="#BC8F8F">&quot;sin curve in z-direction&quot;</FONT></B>;
        my_header.id_lines_1_to_5[2] = <B><FONT COLOR="#BC8F8F">&quot;line in x-direction&quot;</FONT></B>;
        
        my_header.record_12[0] = libMesh::pi;
        
        mesh_data.set_unv_header(&amp;my_header);
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::string second_out_data=<B><FONT COLOR="#BC8F8F">&quot;data_second_with_header_out.unv&quot;</FONT></B>;
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing MeshData to: &quot;</FONT></B> &lt;&lt; second_out_data &lt;&lt; std::endl;
        mesh_data.write(second_out_data);
        
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Before clearing the MeshData:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;-----------------------------&quot;</FONT></B> &lt;&lt; std::endl;
        mesh_data.print_info();
  
        mesh_data.clear();
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;After clearing the MeshData:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;----------------------------&quot;</FONT></B> &lt;&lt; std::endl;
        mesh_data.print_info();
  
        mesh_data.read(first_out_data);
        
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;After re-reading the first file:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;--------------------------------&quot;</FONT></B> &lt;&lt; std::endl;
        mesh_data.print_info();
  
      }
  
  
  
  
  
  
  
  
  
  
  
      
      <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  	      &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;----------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl
  	      &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;---------- next example with MeshData --------&quot;</FONT></B> &lt;&lt; std::endl
  	      &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;----------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl;
  
      {
        Mesh mesh(dim);
        MeshData mesh_data(mesh);
        
        mesh.read(mesh_file, &amp;mesh_data);
        
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;De-activated MeshData:&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;----------------------&quot;</FONT></B> &lt;&lt; std::endl;
        mesh.print_info();
        mesh_data.print_info();
   
        <B><FONT COLOR="#228B22">const</FONT></B> std::string out_mesh = <B><FONT COLOR="#BC8F8F">&quot;mesh_with_libmesh_ids.unv&quot;</FONT></B>;
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing _Mesh_ to: &quot;</FONT></B> &lt;&lt; out_mesh &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Try 'diff &quot;</FONT></B> &lt;&lt; out_mesh &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot; &quot;</FONT></B> &lt;&lt; mesh_file &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;'&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;to see the differences in node numbers.&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;---------------------------------------&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; std::endl;
        mesh.write(out_mesh, &amp;mesh_data);
  
        {
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::map&lt;<B><FONT COLOR="#228B22">const</FONT></B> Node*, std::vector&lt;Number&gt; &gt; artificial_data;
  	create_artificial_data (mesh, artificial_data);
  	mesh_data.insert_node_data(artificial_data);
        }
  
        mesh_data.enable_compatibility_mode();
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::string mesh_data_file = <B><FONT COLOR="#BC8F8F">&quot;data_third_with_libmesh_ids_out.unv&quot;</FONT></B>;
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing MeshData to: &quot;</FONT></B> &lt;&lt; mesh_data_file &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;----------------------------------------------------------&quot;</FONT></B> 
  		&lt;&lt; std::endl &lt;&lt; std::endl;
        mesh_data.write (mesh_data_file);
  
  #ifdef HAVE_ZLIB_H
  
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::string packed_mesh_data_file =  <B><FONT COLOR="#BC8F8F">&quot;packed_&quot;</FONT></B> + mesh_data_file + <B><FONT COLOR="#BC8F8F">&quot;.gz&quot;</FONT></B>;
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing gzip'ed MeshData to: &quot;</FONT></B> &lt;&lt; packed_mesh_data_file &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;---------------------------------------------------------------------------&quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot; To verify the integrity of the packed version, type:&quot;</FONT></B> &lt;&lt; std::endl &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;   gunzip &quot;</FONT></B> &lt;&lt; packed_mesh_data_file &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;; &quot;</FONT></B> &lt;&lt; std::endl
  		&lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;   diff packed_&quot;</FONT></B> &lt;&lt; mesh_data_file &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot; &quot;</FONT></B> 
  		&lt;&lt; mesh_data_file &lt;&lt; std::endl &lt;&lt; std::endl;
        
        mesh_data.write (packed_mesh_data_file);
        
  #endif
  
  
  
  
  
  
        
        {
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::vector&lt;Number&gt; translated_data;
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::vector&lt;std::string&gt; data_names;
  	
  	mesh_data.translate (mesh,
  			     translated_data,
  			     data_names);
  
  
  	<B><FONT COLOR="#228B22">const</FONT></B> std::string gmv_file = <B><FONT COLOR="#BC8F8F">&quot;data_and_mesh_out.gmv&quot;</FONT></B>;
  	<B><FONT COLOR="#5F9EA0">std</FONT></B>::cout &lt;&lt; std::endl 
  		  &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;Writing the data from the MeshData to the GMV file &quot;</FONT></B> 
  		  &lt;&lt; gmv_file &lt;&lt; std::endl
  		  &lt;&lt; <B><FONT COLOR="#BC8F8F">&quot;------------------------------------------------------------------------&quot;</FONT></B> 
  		  &lt;&lt; std::endl;
  	
  	GMVIO(mesh).write_nodal_data (gmv_file,
  				      translated_data,
  				      data_names);
  	
        }
        
      }
    }
  
    <B><FONT COLOR="#A020F0">return</FONT></B> libMesh::close();
  }
  
  
  
  
  
  
  
  
  <B><FONT COLOR="#228B22">void</FONT></B> create_artificial_data (<B><FONT COLOR="#228B22">const</FONT></B> Mesh&amp; mesh,
  			     <B><FONT COLOR="#5F9EA0">std</FONT></B>::map&lt;<B><FONT COLOR="#228B22">const</FONT></B> Node*, std::vector&lt;Number&gt; &gt;&amp; art_data)
  {
    <B><FONT COLOR="#5F9EA0">MeshTools</FONT></B>::BoundingBox b_box = MeshTools::bounding_box(mesh);
  
    <B><FONT COLOR="#228B22">const</FONT></B> Real z_min = b_box.first (2);
    <B><FONT COLOR="#228B22">const</FONT></B> Real z_max = b_box.second(2);
    assert (fabs(z_max-z_min) &gt; TOLERANCE);
  
    <B><FONT COLOR="#228B22">const</FONT></B> Real x_min = b_box.first (0);
    <B><FONT COLOR="#228B22">const</FONT></B> Real x_max = b_box.second(0);
    assert (fabs(x_max-x_min) &gt; TOLERANCE);
  
  
  
    <B><FONT COLOR="#5F9EA0">MeshBase</FONT></B>::const_node_iterator       node_it  = mesh.nodes_begin();
    <B><FONT COLOR="#228B22">const</FONT></B> MeshBase::const_node_iterator node_end = mesh.nodes_end();
  
    <B><FONT COLOR="#A020F0">for</FONT></B> (; node_it != node_end; ++node_it)
      {
        <B><FONT COLOR="#5F9EA0">std</FONT></B>::vector&lt;Number&gt; node_data;
        node_data.resize(2);
  
        <B><FONT COLOR="#228B22">const</FONT></B> Point&amp; p = **node_it;
  	
        <B><FONT COLOR="#228B22">const</FONT></B> Real z_normalized = (p(2)-z_min)/(z_max-z_min);
        <B><FONT COLOR="#228B22">const</FONT></B> Real x_normalized = (p(0)-x_min)/(x_max-x_min);
  
        node_data[0] = sin(2*libMesh::pi*z_normalized);
        node_data[1] = x_normalized;
        
        art_data.insert (std::make_pair(*node_it,node_data));
      }
  }
</pre> 
<a name="output"></a> 
<br><br><br> <h1> The console output of the program: </h1> 
<pre>
***************************************************************
* Running Example  ./ex12-devel -d 3 ../../examples/ex8/pipe-mesh.unv
***************************************************************
 

Finished reading the mesh.  MeshData is active but empty:
---------------------------------------------------------
 Mesh Information:
  mesh_dimension()=3
  spatial_dimension()=3
  n_nodes()=3977
  n_elem()=3520
   n_local_elem()=3520
   n_active_elem()=3520
  n_subdomains()=1
  n_processors()=1
  processor_id()=0

 MeshData Information:
  object activated.


After inserting artificial data into the MeshData:
--------------------------------------------------
 MeshData Information:
  object activated.
  Element associated data initialized.
   n_val_per_elem()=0
   n_elem_data()=0
  Node associated data initialized.
   n_val_per_node()=2
   n_node_data()=3977

Writing MeshData to: data_first_out_with_default_header.unv

Attach our own MeshDataUnvHeader to the MeshData:
-------------------------------------------------
 (note the warning: the number of values per node in
  my_header is not correct)

Writing MeshData to: data_second_with_header_out.unv
WARNING: nvaldc=3 of attached MeshDataUnvHeader object not valid!
         re-set nvaldc to 2

Before clearing the MeshData:
-----------------------------
 MeshData Information:
  object activated.
  Element associated data initialized.
   n_val_per_elem()=0
   n_elem_data()=0
  Node associated data initialized.
   n_val_per_node()=2
   n_node_data()=3977


After clearing the MeshData:
----------------------------
 MeshData Information:
  object activated.


After re-reading the first file:
--------------------------------
 MeshData Information:
  object activated.
  Element associated data initialized.
   n_val_per_elem()=0
   n_elem_data()=0
  Node associated data initialized.
   n_val_per_node()=2
   n_node_data()=3977


----------------------------------------------
---------- next example with MeshData --------
----------------------------------------------

De-activated MeshData:
----------------------
 Mesh Information:
  mesh_dimension()=3
  spatial_dimension()=3
  n_nodes()=3977
  n_elem()=3520
   n_local_elem()=3520
   n_active_elem()=3520
  n_subdomains()=1
  n_processors()=1
  processor_id()=0

 MeshData neither active nor in compatibility mode.

Writing _Mesh_ to: mesh_with_libmesh_ids.unv
Try 'diff mesh_with_libmesh_ids.unv ../../examples/ex8/pipe-mesh.unv'
to see the differences in node numbers.
---------------------------------------


*************************************************************************
* WARNING: MeshData neither active nor in compatibility mode.           *
*          Enable compatibility mode for MeshData.  Use this Universal  *
*          file with caution: libMesh node and element ids are used.    *
*************************************************************************


Writing MeshData to: data_third_with_libmesh_ids_out.unv
----------------------------------------------------------


Writing gzip'ed MeshData to: packed_data_third_with_libmesh_ids_out.unv.gz
---------------------------------------------------------------------------
 To verify the integrity of the packed version, type:

   gunzip packed_data_third_with_libmesh_ids_out.unv.gz; 
   diff packed_data_third_with_libmesh_ids_out.unv data_third_with_libmesh_ids_out.unv


Writing the data from the MeshData to the GMV file data_and_mesh_out.gmv
------------------------------------------------------------------------
 
***************************************************************
* Done Running Example  ./ex12-devel
***************************************************************
</pre>
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