Description

EVALEXPRP Evaluate expression in grid/mesh points.

[ VEVAL ] = EVALEXPRP( S_EXPR, PROB, SOLNUM, IND ) Evaluates the expression EXPR in the grid/mesh points (PROB.grid.p), using FEM interpolation of data given in the FEA model/problem struct PROB.

SOLNUM is an optional scalar integer indicating the solution/time to use in the evaluation (PROB.sol.u(:,SOLNUM), defaults to the last available solution "size(PROB.sol.u, 2)").

IND is also an optional index vector indicating grid points to evaluate (defaults to all 1:n_p).

The resulting evaluated values are returned in a column vector VEVAL with one value for each evaluation point. Points outside the grid/geometry will by default return invalid/NaN (Not-a-Number) values. The resulting values can then be saved/exported in various formats using built-in functions such as SAVE, CSVWRITE, and XLSWRITE.

Input       Value/[Size]           Description
-----------------------------------------------------------------------------------
s_expr      string                 Expression to evaluate
prob        struct                 FEA model/problem definition struct
solnum      scalar int {n_sols}    Solution number/time to evaluate
ind         vector int {1:n_p}     Index to grid points for which to evaluate
                                                                                  .
Output      Value/(Size)           Description
-----------------------------------------------------------------------------------
vEval       [n_ind,1]              Output/result vector of evaluated values

Example

  1) Evaluate the mean of the temperature derivative in the mesh points at time t=100 s.

  fea = ex_heattransfer5('iplot', false);  % Use example script to generate FEA data struct.
  solnum = find(fea.sol.t == 100);

  magTx = evalexprp('sqrt(Tx^2 + Ty^2)', fea, solnum);
  mean(magTx)

See also: evalexpr

evalexprp.m File Reference

Description