====== Appendix 16: Modification of the variable data file (.f02 or .f03) using MODVAR program ======
The MODVAR program (\\Obelix\c\Progs\sources\UtilLaga\MODVAR) allows the modification of nodal variables or element variables (stresses and state variables) using a .MDV file. \\
\\
The structure of the *.MDV file depends on the value of ITMDV: the data is either defined by a list of nodes and elements or by groups of elements. \\

===== Case 1: ITMDV = 0 =====
The structure of the file is the following:
^(A5)^^
|Title1|"NODES" in the first 5 columns)|
^(I5, G10.0, 11I5) - repeated as many times as necessary^^
|IDDL|Number of the DOF to modify|
|VALUE|New value for the nodal variable to modify|
|NODEM(11)|List of nodes for which the variable must be modified \\ If NODEM(I)<0, then the variable is modified for every node from NODEM(I-1) to NODEM(I)|
^1 blank line^^
^(A5)^^
|Title2|"ELEMT" in the first 5 columns)|
^(I5, G10.0, 11I5) - repeated as many times as necessary^^
|ISQ|Position in [[appendices:a22#SIGA|SIGVA]] of the element variable to modify|
|VALUE|New value for the element variable to modify|
|NELEM(11)|List of elements for which the variable must be modified \\ If NELEM(I)<0, then the variable is modified for every node from NELEM(I-1) to NELEM(I)|
^1 blank line^^

===== Case 2: ITMDV = 1 =====
Definition by groups of elements.
^(A5)^^
|Title1|"NODES" in the first 5 columns)|
^(I5, G10.0, 11I5) - repeated as many times as necessary^^
|IDDL|Number of the DOF to modify|
|VALUE|New value for the nodal variable to modify|
|NGROM(11)|List of element groups for which the variable must be modified \\ If NGROM(I)<0, then the variable is modified for every group from NGROM(I-1) to NGROM(I)|
^1 blank line^^
^(A5)^^
|Title2|"ELEMT" in the first 5 columns)|
^(I5, G10.0, 11I5) - repeated as many times as necessary^^
|ISQ|Position in [[appendices:a22#SIGA|SIGVA]] of the element variable to modify|
|VALUE|New value for the element variable to modify|
|NGROM(11)|List of element groups for which the variable must be modified \\ If NGROM(I)<0, then the variable is modified for every group from NGROM(I-1) to NGROM(I)|
^1 blank line^^

For this case, it is necessary to also have a *.dat file extracted from the *.lag file containing all the groups of solid elements. \\
:!: This file must not contain unidimensional elements (such as LICHA, FAIL2, ...). It should only contain solid elements.