Abstract: Some embodiments of the invention provide a method of identifying global routes for nets in a region of a layout with multiple layers, where each net has a set of routable elements. The method partitions each layer of the region into several sub-regions. For each net, the method then identifies a route that connects the sub-regions that contain the net's set of routable elements. Some of the identified routes have at least one non-Manhattan edge and traverse sub-regions on multiple layers.

Abstract: A method for routing of some embodiments defines global routes for nets in an arbitrary region of a circuit layout in which each net has a set of pins. The method uses a first set of lines of measure the length of the global routes, a second set of lines to measure congestion of the global routes, and a third set of lines to partition the arbitrary region into a first set of sub-regions. For each net, the method identifies a global route that connects a group of first-set sub-regions that contain the net's set of pins.

Abstract: Disclosed are methods and systems for formulating a wirelength estimate that takes into account whether any of the routing directions are unavailable. Under certain circumstances, one or more of the routing layers may not be available for routing a wire. If this occurs, then the bounding box that is determined for performing the wirelength estimate would take into account the unavailability of the layer.

Abstract: Some embodiments of the invention provide a method of identifying a group of routes for a set of nets. The group of routes includes one route for each net in the set of nets. The method identifies a set of routes for each net. It then iteratively selects one identified route for each net. During each iteration, the method selects the identified route that least increases a tracking cost that accounts for each of the previously selected routes.

Abstract: Some embodiments of the invention provide a method of searching for a three-dimensional global path between first and second sets of routable elements in a region of a layout that has multiple layers. The method partitions the region into several sub-regions. It then performs a path search to identify a path between a first set of sub-regions that contains the first-set elements and a second set of sub-regions that contain a second-set element. When the method performing the path search, it explores expansions along Manhattan and non-Manhattan routing directions between the sub-regions on a plurality of layers.

Abstract: Some embodiments of the invention provide a method of searching for a global path between first and second sets of routable elements in a region of a layout. The method partitions the region into several rectangular sub-regions. It then identifies a set of sub-regions that contain the two sets of elements. Next, it performs a path search to identify a set of path expansions between a sub-region that contains a first-set element and a sub-region that contains a second-set element. When the method performs the path search, it explores expansions along non-Manhattan directions between the sub-regions.

Abstract: Some embodiments of the invention provide a method of routing nets in a region of a layout with multiple layers. The method defines a routing graph that has several of nodes on plurality of layers, where each node represents a sub-region on a layer. In the graph, there is a set of edges between the nodes on each layer. On one layer, there is at least one set of edges that are neither orthogonal nor parallel to a set of edges on another layer. The method uses this routing graph to identify routes.

Abstract: Some embodiments of the invention provide a method for constructing a convex polygon that encloses a set of points in a region. This method identifies a first polygon that encloses the set of points. It then identifies a second polygon that encloses the set of points. The method then specifies the convex polygon as the intersection of the first and second polygons.

Abstract: Some embodiments of the invention provide a method of searching for a path. The method identifies a set of source and target elements. It then performs a path search that iteratively identifying path expansions in order to identify a set of associated path expansions that connect the source and target elements. The method costs at least one expansion based on an exponential equation that has an exponent that includes a cost associated with the expansion.

Abstract: Some embodiments of the invention provide a method of defining a global route for a net in a region of a layout, where each net has a set of routable elements. The method partitions the region into several rectangular sub-regions. It then identifies a set of sub-regions that contain the routable elements of the net. Next, it defines a global route that connects the identified sub-regions, where the global route includes at least one non-Manhattan edge that crosses a boundary between two sub-regions at a non-vertex location.

Abstract: Some embodiments of the invention provide a method that computes an estimated distance between an external point and a set of points in the region. This method identifies a characteristic of the set of points. Based on the identified characteristic, the method then identifies a polygon that encloses the set of points. It then identifies a distance between the point and the polygon. Finally, it uses the identified distance to identify the estimated distance.

Abstract: Some embodiments of the invention provide a method for routing. The method defines at least one wiring layer that has at least two regions with different local preferred wiring directions. The method then uses the differing local preferred wiring directions to define a global route on the wiring layer. The two regions are a first region with a first local preferred wiring direction, and a second region with a second local preferred wiring direction. The global route traverses the first region along the first local preferred wiring direction and traverses the second region along the second local preferred wiring direction.

Abstract: Some embodiments of the invention provide a method for defining wiring directions in a design layout having several wiring layers. The method decomposes a first wiring layer into several non-overlapping regions. It assigns at least two different local preferred wiring directions to at least two of the regions. In some embodiment, the method decomposing the first wiring layer by using the vertices of items in the layout to decompose the layout. In some of these embodiments, the item include macro blocks. The method of some embodiments also identifies several power via arrays on the first wiring layer, and identifies a local preferred wiring direction based on the arrangement of the power via arrays on the first wiring layer.

Abstract: Some embodiments of the invention provide a method of costing routes for a set of nets. The method identifies at least one route for each net, where each route has a particular length. It also identifies an estimated route length for each net. It then computes a cost that includes an exponential expression for each net. Each net's exponential expression includes a base and an exponent. The exponent of each net's exponential expression includes the length of the net's route divided by the estimated route length for the net.

Abstract: Some embodiments of the invention provide a method that computes an estimated distance between an external point and a set of points in a region. This method initially identifies a non-Manhattan polygon that encloses the set of points. It then identifies a distance between the external point and a point on the boundary or within the first non-Manhattan polygon. Finally, it uses the distance to identify the estimated distance.

Abstract: Some embodiments of the invention provide a method of solving an optimization problem. The problem includes a plurality of elements, and one or more solutions have been previously identified for each element. The method specifies a first solution set that has one identified solution for each element. In some embodiments, the method then iteratively examines all the elements of the problem. During the examination of each particular element, the method iteratively examines all the identified solutions for the particular element. During the examination of each particular solution, the method replaces the current solution for the particular element in the first solution set with a previously unexamined solution for the particular element if the replacement would improve the first set.

Abstract: Some embodiments of the invention provide a method of identifying global routes for nets in a region of a layout with multiple layers, where each net has a set of routable elements. The method partitions each layer of the region into several sub-regions. For each net, the method then identifies a route that connects the sub-regions that contain the net's set of routable elements. Some of the identified routes have at least one non-Manhattan edge and traverse sub-regions on multiple layers.

Abstract: Some embodiments of the invention provide a method of routing nets in a region of a layout with multiple layers. The method defines a routing graph that has several of nodes on plurality of layers, where each node represents a sub-region on a layer. In the graph, there is a set of edges between the nodes on each layer. On one layer, there is at least one set of edges that are neither orthogonal nor parallel to a set of edges on another layer. The method uses this routing graph to identify routes.

Abstract: Some embodiments of the invention provide a method of identifying a group of routes for a set of nets. The group of routes includes one route for each net in the set of nets. The method identifies a set of routes for each net. It then iteratively selects one identified route for each net. During each iteration, the method selects the identified route that least increases a tracking cost that accounts for each of the previously selected routes.

Abstract: Some embodiments of the invention provide a method of searching for a path. The method identifies a set of source and target elements. It then performs a path search that iteratively identifying path expansions in order to identify a set of associated path expansions that connect the source and target elements. The method costs at least one expansion based on an exponential equation that has an exponent that includes a cost associated with the expansion.