Widget:
- There is no widget for this command.
Command:
- FREE = field
Arguments :
- field: the field name which will be deleted from memory.
Examples :
- FREE = UWIND
Notes :
- This command is most useful when machine memory limits are reached, and no more fields may be read in. If a data file, which has been previously read containts 4 fields (variables), i.e. A, B, C and D, each one of these variables has assigned location in the memory. Let's suppose we can picture their sequence in the memory as ...A...B...C...D.... (There may be a gap between variables since IVE allocates additional memory for its own use from time to time). If for example user types in command 'FREE = B', then space used by B is freed up, thus: ...A...free...C...D.... The total allocated memory is however still the same (from A to D). This is also true even if the last field was freed up (i.e. 'FREE = D' which results in ...A...B...C...) and there apparently is more memory available. Freeing of memory doesn't show up as long as IVE is running. If a new field is being invoked, or a new file is being read in, then the freed space can be used if the new variable uses equal or lesser amount of memory. In our case, we were left with ...A...free...C...D.... The new file contains variable X. If X takes less memory than B, then it will fit into the vacant slot ...A...X...C...D... and the total allocated memory remains the same. If X takes more memory than B, it will be positioned at the end, ...A...free...C...D...X.... If the goal of freeing the space was to avoid exceeding a memory size limit, then in the latter example X can not be read in - a larger block of continuous memory has to be freed.