%--------------------------------------------------------------------------
% ELEMENT.B_mat
%--------------------------------------------------------------------------
% Computation of B matrix evaluated at the integration points.
%--------------------------------------------------------------------------
% Syntax
%--------------------------------------------------------------------------
Bmat = B_MAT(EL1,MO1,IR)
Bmat = ELEMENT.B_MAT(EL1,MO1,IR)
%--------------------------------------------------------------------------
% Description
%--------------------------------------------------------------------------
% The B_mat method of the ELEMENT class is used to compute the B matrix
% at the integration points.
%--------------------------------------------------------------------------
% Input arguments
%--------------------------------------------------------------------------
% EL1 : ELEMENT object
% MO1 : MODEL object
% IR : INT_RULE object
%--------------------------------------------------------------------------
% Output arguments
%--------------------------------------------------------------------------
% Bmat : 1 x npg cell - npg being the number of integration points.
% Bmat{k} is the B matrix associated with the kth integration
% point of the element EL1.
%--------------------------------------------------------------------------
% Example
%--------------------------------------------------------------------------
% Case of a QUA4 ELEBmat
Bmat =
[3x8 double]
[3x8 double]
[3x8 double]
[3x8 double]
Bmat{3}
ans =
-7.8868 0 -2.1132 0 2.1132 0 7.8868 0
0 2.1132 0 -2.1132 0 -7.8868 0 7.8868
2.1132 -7.8868 -2.1132 -2.1132 -7.8868 2.1132 7.8868 7.8868