the output of the boolean operations that form the foundation of these algorithms are regular and well defined point sets and that these point sets are defined by well defined polygonal boundaries round off errors during boolean computations can cause algorithm failures without warning these undetected errors can cause severe consequences including wasted computation time due to ambiguous or wrong results or even defective dies due to undetected errors drc are checks performed before integrated circuit manufacturing to ensure that in the placed and routed technology mapped design the actual dimensions and locations of the shapes making up a wire or other feature in the chip none of the rules of the target technology process is violated examples for such drc are checks for shorts spacing violations or other design rule problems between logic cells an example for a tool that does drc is dracula from cadence design systems inc in san jose calif the group of steps comprising design verification 940 are performed next first the construction of generated metal fill shapes and metal hole shapes is done using standard drc tools to verify that the following prescribed values are observed mxfill outside mx mxfill outside mxexclud e g logos fuse bays mxhole inside mx mxhole outside vx vx u2212 1 mxhole outside mxchexcl where for example u201c m 1 fill outside m 1 u201d refers to a rule requiring that all m 1 fill shapes must lie outside any m 1 shape by at least a prescribed minimum distance similarly u201c m 2 hole inside m 2 u201d refers to a.