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An Image file contains all of the information needed to define the position and orientation of all symmetric images of the primary atoms. The file is a card image file and a sample file is given:

* IMAGE FILE FOR BETA SHEET TEST CASE * ONLY ONE TRANSFORMATION (Z AXIS ROTATION) * 1 1.0 1.0 1.0 ZROT -1.0 0.0 0.0 0.0 -1.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0

The title is in standard CONGEN format, see Syntactic Glossary.
The next contains the number of transformations (`I5`

). The
following line contains the unit cell dimensions (multiplying factors)
(`3F10.5`

).

The remaining lines are in groups of five, one group for each
transformation . For each group, the first line contains the name of the
transformation (`A8`

). The next three lines contains the rotation
matrix, and the last line contains the translation vector (all
`3F10.5`

).

The rotation matrix must be unitary, however, a non-unitary
rotation matrix will only result in a warning. The use of an anti-unitary
matrix can be used to include the mirror image of any system into the
calculation. The values of the translation vector are multiplied by the
cell dimensions listed at the beginning of the file to generate the actual
translation steps. For the use in this program the translation is done
*after* the rotation has been made.

One other restriction on the transformations is that every
transformation *must* have an inverse. Again, there is only a
warning if this restriction is violated as there may be examples where
this is desired. In the example above, this transformation is its own
inverse. Non-physical results will be obtained if this restriction is
violated.

The maximum number of allowed transformations is 26 (the number
needed for simple 3-dimensional periodic boundaries). This limit can
easily be increased by modifying `INIMAG`

.

For other examples of image files see the test cases.