DALTON is designed to exit gracefully if there is
not enough memory at some stage of the calculation. Wherever
possible, it will indicate how much additional memory is required for this
particular section. This does not exclude the possibility that the
calculation will use even more memory at later stages of the
calculation. If DALTON aborts in the response calculation, it may be
possible to proceed by resetting the number of perturbations handled
simultaneously (see for instance Sec. 
). Otherwise some
redimensioning will be necessary.
The program use approximately 0.8 Mw of memory allocated as common
blocks and similar data structures. Most of the memory used during the
calculation is taken from a large work array. The size of this work
array ,
MEMWRK , is supplied to the program as a shell
variable. How this is done is
exemplified in the chapter on how to get started
(Chapter ). This makes it easy
to give the program the memory needed for a given calculation. It is
worth noticing that some computers using batch queue systems often
give priority to jobs according to their memory requirements, and it may
therefore be of interest to minimize the requested memory in order to
get the jobs faster through (real time). If no value to the shell
variable is supplied, the program will use the default value which is
determined at installation time from the variable
INSTALL_WRKMEM in the preprocessor
directives .