fe_def

Contents Functions

fe_def

Purpose

Utilities for FEM related data structures.

Syntax

 ... = fe_def(def,'command', ... )
 ... = fe_def('command', ... )

Description

Accepted commands are

SubDef, SubDof, SubCh

def=fe_def('SubDef',def,ind); keeps deformations associated with ind, which a vector of indices or a logical vector (for example ind=def.data(:,1)<500 can be used to select frequencies below 500). Other fields of the def structure are truncated consistently.

def=fe_def('SubDof',def,DOF) is extracts a subset of DOFs based on defined DOF or with def=fe_def('subdofind',def,ind) indices (again either values or logicals). This command is partially redundant with feutilb PlaceInDof called with def2 = feutilb('PlaceInDof',DOF,def). The main difference is the ability to add zeros (use DOF larger than def.DOF) and support sens structures.

fe_def('SubDofInd-Cell',def,ind_dof,ind_def) returns a clean cell array listing selected DOFs and responses. This is typically used to generate clean tables.

fe_def('SubCh',def,ind) is similar to SubDof but allows but supports more advanced selection for multi-dimensional curves. This command is not fully documented.

DefFreq

w=fe_def('DefFreq',DISK) returns frequencies defined in the info,Freq entries using Hz units.

Range

Range commands are used to manipulate experiment (series of design points) specifications. A range is a data structure with fields

.val numeric array containing one design point per row and one design parameter per column.
.lab cell array of strings giving a parameter label for each column. These labels should be acceptable fieldnames (no spaces, braces, ...)
.param optional structure with fields associated with parameter labels used for formatting and analysis. Accepted values are detailed below. It is not necessary to define a .param field for each design parameter.
.edge optional connectivity matrix used to define lines connecting different design points of the experiment

Acceptable .param field entries are

.type a string. Typically double or pop.
.choices, for .type='pop', contains a cell array of strings. The parameter value then gives the index within .choices
.LabFcn a command to be evaluated with st1=eval(r2.LabFcn) to generate the proper label. For example 'sprintf(”%.1f ms”,val/1000)' is used to generate a label in a different unit.
.level is an integer specifying the computational step at which a given parameter can be modified. This is used to generate experiment trees.

RangeGrid

Range=fe_def('RangeGrid',par);
Range is defined by a grid of all the parameter values defined in par. par is expected as a cell array with as many elements as parameters. Each cell can be

a string 'lab "label" min min max max cur cur scale "scale" NPoints NPoints'. "label" is the parameter name. Then the minimum, maximum and nominal values are defined. Scale can be "lin" for linear scale or "log" for logarithmic scale. NPoints defines the number of point for the parameter vector.
a range data structure
a numeric vector in the old upcom format [type cur min max scale] with type defining the matrix type (unused here), scale==2 indicates a logarithmic variation.

par can also be a matrix following the model of the visco tools parameters definition (see fevisco Range for more details).

As an illustration, following example defines a grid 6x7 of 2 parameters named length and thickness:

par={'lab "length" min 10 max 20 cur 10 scale "lin" NPoints 6',...
     'lab "thickness" min 1e-3 max 2e-3 cur 0 scale "log" NPoints 7'};
Range=fe_def('RangeGrid',par);

RangeVect

Range=fe_def('RangeVect',par);
Simply concatenate all parameter ranges (they must have the same length).

RangeRes

R1=fe_def('RangeRes',R1,Range);
This command reshapes the last dimension of the result curve R1 according to the Range. For a grid DOE last dimension is split in as many dimensions as parameters. For a vector DOE, last dimension is only redefined by a cell array of labels defining each design point.