Description

MINMAXBDR Calculate minima and maxima of an expression on boundaries.

[ MIN_VAL, MAX_VAL, MIN_COORD, MAX_COORD ] = MINMAXBDR( S_EXPR, PROB, IND_B, I_CUB, SOLNUM ) Evaluates the mimimum and maximum value of expression S_EXPR on boundaries, using FEM interpolation of data given in the FEA model/problem struct PROB.

The string expression S_EXPR must be valid MATLAB syntax, and may include combinations of dependent variables (defined in PROB.dvar) and derivatives, space dimensions (PROB.sdim), and all common built-in constants and mathematical functions available, such as pi, eps, sqrt, sin, cos, log, exp, abs etc (for example "sin(2*pi*x + ux^2)" where "ux" is the x-derivative of the dependent variable "u").

The optional vector IND_B are indices to boundaries to include in the evaluation (default all "unique(PROB.grid.b(3,:))").

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)").

Returns the computed minima and maxima in MIN_VAL and MAX_VAL, and the corresponding coordinates where the minima/maxima occurs in MIN_COORD and MAX_COORD, respectively.

Input       Value/[Size]           Description
-----------------------------------------------------------------------------------
s_expr      string                 Expression to evaluate
prob        struct                 FEA model/problem definition struct
ind_b       [1,n_bdr]              Boundary numbers (default all)
i_cub       scalar int             Evaluation point rule/quadrature order (default 2)
solnum      scalar int {n_sols}    Solution number/time to evaluate
                                                                                  .
Output      Value/[Size]           Description
-----------------------------------------------------------------------------------
min_val     scalar                 Minimum value of expression
max_val     scalar                 Maximum value of expression
min_coord   scalar                 Coordinates where minima occurs
max_coord   scalar                 Coordinates where maxima occurs

Example

  1) Evaluate minimum and maximum temperature on boundaries at time t=100 s.

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

  [T_min, T_max, T_min, T_max] = minmaxbdr('T', fea, solnum)

See also: minmaxsubd, intbdr, intsubd

minmaxbdr.m File Reference

Description