Software Limitations and Bugs

The ALADDIN software package is still in development. Here is a list of software limitations and bugs that we know about:

[ Matrix Library ]
[ Finite Element Library ]

If you find a programming error, or a component of the software that has not been implemented (and should have been), please let us know by sending E-mail to austin@isr.umd.edu.

MATRIX PACKAGE

The matrix function PrintMatrixCast() works for statements of the type
```
        PrintMatrixCast ( A, [cm]);
```
where the units conversion is a built-in name. We need to extend the language so that commands of the type
```
        PrintMatrixCast ( A, [cm/sec/sec] );
```
will also work.
When the Stiff() function is used to compute a finite element stiffness matrix, as in:
```
        stiff = Stiff();
```
ALADDIN will return a global stiffness matrix stored in skyline storage. We currently assume that the stiffness matrix will be symmetric (although some applications will lead to non-symmetric matices).

It is conceivable that with the stiffness matrix in hand, some users may wish to modify its contents will statements of the type:
```
        stiff [2][1] = 10^10 N/m;
```
Assignments of this type are not supported because they will destroy the matrix symmetry.

FINITE ELEMENT LIBRARY

So far we have only implemented units computations in the 2-D and 3-D beam finite elements. Units computations are missing from the plane-stress/plane-strain element, the four node shell element (with drilling d.o.f.), and the plate finite element.
Mass matrix computations are missing from the four node shell element (with drilling d.o.f.), and the plate finite element.
The GetDispl() and GetStress() functions have only been implemented in the 2-D and 3-D beam finite elements.
We are currently adding these functions to the plane stress/plane strain elements.
We suspect there is a small bug in the plane stress/plane strain element. This is being checked out, and we will present example web pages and the corrected element soon (i.e., before the end of July 1997).
The DQK plate element needs to be checked for accuracy of numerical results (see elmt_plate.c).

If you decide to add/fix some of these features, please e-mail austin@isr.umd.edu, and we will get you the appropriate code to work on.