| 摘要 |
PURPOSE:To obtain the deciding system of optimum variable order for case separation by comprising a system in such a way that a logical expression representing a logical function can be simplified by developing to a sum of products format, and the order of a variable with many product item numbers is set as a variable order when a binary decision graph for two-stage logic circuit is generated. CONSTITUTION:Firstly, the logical expression representing the logical function for two-stage logic is developed to the sum of products format, and is simplified at step 1. The product item number in which each variable appearing in the logical expression is used in an affirmative or negative format is checked, respectively at step 2, and the variable order when the binary decision graph is generated is decided according to an order of more product item numbers at step 3. When the variable appears in the affirmative format in the product item, it is expressed, for example, as 1, and as 0 when it appears in the negative format, and (-) when no variable appears, and the variable with more numbers of 0 and 1 is set as the variable order of the binary decision graph by counting the numbers at every column. |
