Placement optimization system aided by CAD
First Claim
1. A placement optimization system aided by CAD comprising:
- input means for inputting circuit connection information including a plurality of placement elements;
placement optimization means for determining a degree of wiring crowdedness based on said circuit connection information and optimizing placement positions of said placement elements by conducting an evaluation of a height of a wiring region statistically approximated from a distribution of the degree of wiring crowdedness and by performing repetitive improvement of the placement positions based on said evaluation; and
output means for outputting placement position information derived by said placement optimization means.
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Accused Products
Abstract
There is provided a placement optimization system for determining layout in printed circuits and semiconductor substrates, comprising input means for inputting circuit connection information, placement optimization means for deriving wiring density distribution on the basis of the circuit connection information, evaluating the height and/or width of the wiring region statistically estimated from the wiring density distribution, and output means for outputting the resultant placement position information. Further, the placement optimization system may comprise means for collecting placement elements into sets, determining placement of the sets, then developing the sets into elements, and determining optimum placement positions of the elements.
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Citations
14 Claims
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1. A placement optimization system aided by CAD comprising:
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input means for inputting circuit connection information including a plurality of placement elements; placement optimization means for determining a degree of wiring crowdedness based on said circuit connection information and optimizing placement positions of said placement elements by conducting an evaluation of a height of a wiring region statistically approximated from a distribution of the degree of wiring crowdedness and by performing repetitive improvement of the placement positions based on said evaluation; and output means for outputting placement position information derived by said placement optimization means. - View Dependent Claims (2, 3, 4)
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5. A placement optimization system aided by CAD for optimizing, in a circuit including mutually related placement elements, placement positions of the placement elements, said placement optimization system comprising:
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input means for inputting circuit connection information including a plurality of placement elements and shape information of said placement elements; initial placement means for initially placing said placement elements at respective placement positions; placement alternation means for moving and interchanging said placement elements and for locally altering the placement positions; final area estimation means for calculating, on the basis of a placement state obtained at each time of placement alteration, an area of a final layout result expected in said placement state and defining the calculated area as an evaluation function value assigned to the respective placement alteration; alternation condition judgment means for evaluating a difference between said evaluation function value assigned to a first said placement alteration and the evaluation function value assigned to a second said placement alteration successive to the first placement alteration and thereby judging satisfaction of a condition of the second placement alteration; placement alteration cancellation means responsive to nonsatisfaction of said condition of said second placement alteration in said alteration condition judgment means to cancel said second placement alteration and restore the placement state and the evaluation function value assigned to said first placement alteration; and end condition judgment means for judging satisfaction of a given end condition, said end condition judgment means being responsive to satisfaction of said end condition to cause an output means to generate placement position information of said placement elements and responsive to nonsatisfaction of said end condition to activate said placement alteration means. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A placement optimization system aided by CAD for optimizing, in a circuit including mutually related placement elements, placement positions of the placement elements, said placement optimization system comprising:
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input means for inputting circuit connection information including a plurality of placement elements and shape information of said placement elements; placement element collection means for generating placement element sets by collecting the placement elements having a close connection relationship in said circuit connection information in each set so as to make areas of the respective sets nearly equal to each other, and defining the placement element sets as new placement elements, and for generating circuit connection information relating to said placement elements sets, and defining the circuit connection information as new circuit connection information; modeling means for assigning the placement elements to placement region lattices of a lattice model including placement region lattices and wiring region lattices; placement alteration means for interchanging said placement elements on the lattice model to perform local placement interchange; final area estimation means for calculating, on the basis of a placement state obtained at each time of execution of placement alteration, an area of a final layout result expected in said placement state and defining the area thus calculated as an evaluation function value assigned to the respective placement alteration; alteration condition judgment means for evaluating a difference between said evaluation function value assigned to a first said placement alteration and the evaluation function value assigned to a second said placement alteration successive to said first placement alteration and for judging, on the basis of the evaluation, satisfaction of the second placement alteration; placement alteration cancellation means responsive to nonsatisfaction of said second placement alteration in said alteration condition judgment means to cancel said second placement alteration and restore the placement state and the evaluation function value assigned to said first placement alteration; end condition judgment means for judging satisfaction of an end condition, said end condition judgment means being responsive to satisfaction of the end condition to cause advancement to succeeding processing and responsive to nonsatisfaction of the end condition to activate said placement alteration means; placement element set development means for opening all placement elements sets assigned to respective placement region lattices of said lattice model and for determining placement positions of all placement elements included in each placement element set; and output means for outputting placement position information. - View Dependent Claims (12, 13, 14)
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Specification