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The !compare Command: Compare Hierarchies

Syntax: !compare arguments
This function compares the geometry and instance placements in cells from two cell hierarchies, or between a cell hierarchy and cells in memory, or between cells in memory. It is also possible to compare properties of cells, cell instances, and objects. The results are written to a log file. It is used as a back-end for the Compare Layouts panel, and can be used directly.

There are three basic comparison modes. The per-cell object mode compares cell content object-to-object. A difference will be indicated if a given object does not have an exact counterpart in the other cell. The per-cell geometry mode does not look at objects, but rather considers the area occupied by the objects. Thus, differences will be indicated only if the covered area differs. The third comparison mode logically flattens the hierarchy before comparing the geometry. Thus, differences will be indicated only if the flat geometry (i.e., the mask layout) differs.

The results are written to a file named ``diff.log'' in the current directory. Each object or region that appears in one cell and not the other corresponding cell is written in a CIF-like format to the log file, unless the -d (diff only) option is given.

When the comparison finishes, the user is given the option to view the log file. The !diffcells command can be used to create cells from the log file for visualizing the differences.



Subsections
next up previous contents index
Next: Common Options Up: Layout Information Previous: The !summary Command: Print   Contents   Index
Stephen R. Whiteley 2017-10-02