%--------------------------------------------------------------------------
% ELEMENT.JT_MAT
%--------------------------------------------------------------------------
% Computation of the Jacobian matrix.
%--------------------------------------------------------------------------
% Syntax
%--------------------------------------------------------------------------
JT = JT_MAT(EL1,elem_type,gp)
JT = ELEMENT.JT_MAT(EL1,elem_type,gp)
%--------------------------------------------------------------------------
% Description
%--------------------------------------------------------------------------
% The JT_MAT method of the ELEMENT class is used to compute Jacobian matrix.
%
%--------------------------------------------------------------------------
% Input arguments
%--------------------------------------------------------------------------
% EL1 : ELEMENT object
% elem_type : STRING describing the type of finite element when a specific
% kinematics is used. It can be equal to:
% - TRUSS : truss element
% - BEAM : standard Euler Bernouilli beam element
% - TIMO, FLI : standard Timoshenko beam element (multifiber
% formulation)
% - FLIG : standard Timoshenko beam element (generalized
% formulation)
% - FCQ : quadratic beam element
% - T3G : T3 - gamma formulation shell FE (3D)
% gp : scalar, vector, matrix - description of the local coordinates
% of the integration points. gp is structured as follows:
% - gp(:,1) : first coordinate of the integration points
% - gp(:,2) : second coordinate of the integration points
% - gp(:,3) : third coordinate of the integration points
%--------------------------------------------------------------------------
% Output arguments
%--------------------------------------------------------------------------
% JT : scalar, vector, matrix - Jacibian latrix. It has the following
% structure:
% - if nvar equal to 1:
% - JT([i],:) is the Jacobian matrix evaluate
% ate the integration point i
%
% - if nvar equal to 2:
% - JT([2*i-1 ; 2*i ],:) is the Jacobian matrix
% evaluated at the integration point i
%
% - if nvar equal to 3:
% - JT([ 3*i-2; 3*i-1; 3*i],:) is the Jacobian matrix
% evaluated at the integration point i
%
%--------------------------------------------------------------------------
% Example
%--------------------------------------------------------------------------
% Case of a QUA4 ELEMENT. gp is:
gp
ans =
-0.5774 -0.5774
0.5774 -0.5774
-0.5774 0.5774
0.5774 0.5774
JT = JT_MAT(obj,mo.elem_type,gp)
JT =
0.0000 -0.0500
0.0500 0.0000
0.0000 -0.0500
0.0500 -0.0000
-0.0000 -0.0500
0.0500 0.0000
-0.0000 -0.0500
0.0500 -0.0000