D3PLOT 22.1

Handling Missing Family Members

Handling missing family members

It is not possible to use any of the database files above if their "root" family member is missing. This contains control, geometry and topology data that is required if the rest of the file family is to be read. However it is possible to process families in which some children have been deleted.

The data written to a file family is: <Control and topology> <state #1> <state #2> ...

and certain rules are used to make selective removal of child family members easier.

(1)	If adding a <state> would overflow the maximum size permitted in the current member, it is closed and a new one is opened.
(2)	A new family member is always started following the writing of a restart dump file.
(3)	If a <state> is too big to fit into a single member then the maximum size rule is still obeyed: the first member is filled to capacity, then the next one is opened to take the remainder of the data. Thus <states> will be written in pairs (or, if large enough, triplets, quadruplets and so on) of family members.

This is best explained by example. Two are given here: one for a moderate size analysis, and one for a huge one. In both cases a maximum family size of 7MB is assumed.

Example 1 : Basic control and topology requires 2MB, each state uses 3MB.

Root member		Child #3	Restart dump => new member
Control + Geometry	2MB	<State #5>	3MB
<State #1>	3MB	<State #6>	3MB

Child #1		Child #4
<State #2>	3MB	<State #7>	3MB (Last state in file)
<State #3>	3MB

Child #2
<State #4>	3MB

Example 2 : Basic control and topology require 8MB, each state 12MB.

Root member		Child #2		Child #4
Control + Geometry	7MB	<State #1: part 1>	7MB	<State #2: part 1>	7MB
(part 1)
		Child #3		Child #5
Child #1		<State #1: part 2>	5MB	<State #2: part 2>	5MB
Control + Geometry	1MB			And so on in pairs
(part 2)

Note that the basic geometry spills into the first child, and that subsequent <states> always come in pairs of files. In this example child family members containing states could be removed, but only in matched pairs.

Hint:

Use the UNIX command ls -lt to look at your files. This will give a "long" listing showing file size, and also sort them into chronological order of creation.

Then look for matched pairs of files that will, in this example, have 7MB and 5MB sizes with the smaller file being marginally more recent.

D3PLOT will skip gaps in a file family sequence if the FILE_SKIP environment variable or the D3PLOT preference file_skip is set. This is an integer that defines how many missing files will be skipped before the search is abandoned. The default value set for the preference and environment variable in the Shell is 50, but values much larger than this (up to 999) could be used. Larger values will increase the time delay when SCAN ning files as children are searched for on disk. See Open a Single Model and The FILE > popup menu options for ways to alter this value at run time.

Previous | Next