[Getfem-commits] r5232 - /trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst

[Yves . Renard]

Author: renard
Date: Mon Feb  1 08:48:59 2016
New Revision: 5232

URL: http://svn.gna.org/viewcvs/getfem?rev=5232&view=rev
Log:
rearrangement of the documentation of linear operators

Modified:
    trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst

Modified: trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst
URL: 
http://svn.gna.org/viewcvs/getfem/trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst?rev=5232&r1=5231&r2=5232&view=diff
==============================================================================
--- trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst        (original)
+++ trunk/getfem/doc/sphinx/source/userdoc/gasm_high.rst        Mon Feb  1 
08:48:59 2016
@@ -262,7 +262,7 @@
   workspace.add_fem_variable("u", mf_u, gmm::sub_interval(0, nbdofu), U);
   workspace.add_fem_variable("p", mf_p, gmm::sub_interval(nbdofu, nbdofp), P);
   workspace.add_fixed_size_constant("mu", vmu);
-  workspace.add_expression("mu*(Grad_u + Grad_u'):Grad_Test_u"
+  workspace.add_expression("2*mu*Sym(Grad_u):Grad_Test_u"
                         "- p*Trace(Grad_Test_u) - Test_p*Trace(Grad_u)", mim);
   getfem::model_real_sparse_matrix K(nbdofu+nbdofp, nbdofu+nbdofp);
   workspace.set_assembled_matrix(K);
@@ -541,15 +541,20 @@
 
 The command ``Reshape(t, i, j, ...)`` reshapes the tensor ``t`` (which could 
be an expression). The only constraint is that the number of components should 
be compatible. For instance  ``Reshape(Grad_u, 1, meshdim)`` is equivalent to 
``Grad_u'`` for u a scalar variable. Note that the order of the components 
remain unchanged and are classically stored in Fortran order for compatibility 
with Blas/Lapack.
 
-Trace operator
---------------
-
-The command ``Trace(m)`` gives the trace (sum of diagonal components) of a 
square matrix ``m``. Since it is a linear operator, it can be applied on test 
functions.
-
-Deviator operator
------------------
-
-The command ``Deviator(m)`` gives the deviator of a square matrix ``m``. It is 
equivalent to ``m - Trace(m)*Id(meshdim)/meshdim``. Since it is a linear 
operator, it can be applied on test functions. 
+Trace, Deviator and Sym operators
+---------------------------------
+
+Trace, Deviator and Sym operators are linear operators acting on square 
matrices:
+
+  - ``Trace(m)`` gives the trace (sum of diagonal components) of a square 
matrix ``m``.
+
+  - ``Deviator(m)`` gives the deviator of a square matrix ``m``. It is 
equivalent to ``m - Trace(m)*Id(meshdim)/meshdim``.
+
+  - ``Sym(m)`` gives the symmetric part of a square matrix ``m``, i.e. ``(m + 
m')/2``.
+
+The three operators can be applied on test functions. Which means that for 
instance both ``Trace(Grad_u)`` and  ``Trace(Grad_Test_u)`` is valid when 
``Grad_u`` is a square matrix (i.e. ``u`` a vector field of the same dimension 
as the mesh).
+
+
 
 Nonlinear operators
 -------------------