The Advanced OASIS Export Parameters Panel: Set
OASIS Parameters

The Advanced OASIS Export Parameters panel is provided from the Advanced button in the OASIS setup page of various panels, including the Export Control panel, the Format Conversion panel and the Layout File Merge Tool, all from the Convert Menu. It allows modification of the more arcane parameters used when generating OASIS output.

Don't write trapezoid records
This check box sets and unsets the OasWriteNoTrapezoids variable. When set, no attempt is made to save three and four-sided polygons in more compact trapezoid records. Setting this variable will likely increase file size but reduce writing time.

Convert Wire to Box records when possible
This check box sets and unsets the OasWriteWireToBox variable. When set, single-segment Manhattan wires will be saved in more compact rectangle records. This may reduce file size, at the expense of slightly longer writing time and loss of object type integrity.

Convert rounded-end Wire records to Poly records
This check box sets and unsets the OasWriteRndWireToPoly variable. When set, rounded-end wires, which don't have native OASIS support and are normally converted to extended-end (Manhattan extension) wires, are instead converted to polygons. The polygons require more memory than the wires, but preserve exactly the geometric coverage of the original layout, as rendered in Xic.

Skip GCD check
This check box sets and unsets the OasWriteNoGCDcheck variable. When set, the OASIS writer will not attempt to divide out a common factor in vertex lists, which is done to reduce file size but can have significant computational overhead.

Use alternate modal sort algorithm
This check box sets and unsets the OasWriteUseFastSort variable. When set, an older, less effective sorting algorithm is used to sequence objects in output to make use of modality. Use of this algorithm may reduce writing time but will potentially increase file size.

Property masking
This menu controls the OasWritePrptyMask variable, which can be used to avoid writing certain, or all properties. This can reduce file size if properties are not needed. The description of this variable explains this feature in detail.

The remaining controls provide an interface for setting the text string for the OasWriteRep variable, which is used to control the repetition finder. Use of the repetition finder is enabled/disabled by the Find repetitions check box in the OASIS page of the Export Control panel. The present panel sets the parameters to use when the repetition finder is enabled.

The repetition finder is a system that will identify identical objects, and attempt to identify periodic sequences of these objects in one and two dimensions. This can have a huge effect on file size, at the expense of computational overhead. The controls on this panel can be used to fine-tune the algorithm for a particular data set, producing, e.g., the smallest file, or reducing writing time.

The description of the OasWroteRep variable provides detailed information about the parameters found in the property string, which has the form:

OasWriteRep: [word] [d] [r] [m=N] [a=N] [x=N] [t=N]

The Restore Defaults button will reset all controls to the default values. The Objects check boxes control which object types are processed for repetitions, as for the word in the string.

The Run minimum is the value passed for the m option. Pressing the None button on this line will instead give the r option, and gray out the run and array controls. The Array minimum provides the value for the a option. The None button on this line will emit ``a=0'' and disable the entry area. The Max different objects line corresponds to the x option. The Max similar objects line corresponds to the t option. If the None button in this line is pressed, ``t=0'' will be emitted and the entry area is grayed. Note that these do not emit if the text area contains the default value.

To actually enable repetitions, the OasWriteReps variable must be set. This can be set by hand with the !set command or equivalent, in which case the controls above will take the values found in the string. Setting the Find repetitions check box in the OASIS page of the Export Control panel will also set the variable, to a string created from the state of the controls. When the variable is set, the listing of set variables brought up with the !set command without arguments can ge used to monitor the property string as the various controls are changed.