Extend ternary truth table operations to handle don't cares#144
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costamag merged 3 commits intolsils:masterfrom May 19, 2025
Merged
Extend ternary truth table operations to handle don't cares#144costamag merged 3 commits intolsils:masterfrom
costamag merged 3 commits intolsils:masterfrom
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This PR enhances the handling of ternary truth tables, which are used to represent incompletely specified Boolean functions (i.e., functions with don't cares). The current implementations of key operations such as
has_varandmin_base_inplacedo not take advantage of don't care conditions.To address this limitation, this PR introduces new versions of these operations that exploit don't cares where applicable. To maintain backward compatibility, a template parameter
UseDCs(default:false) is added. When set totrue, the updated implementations are used; otherwise, the behavior falls back to the existing logic.New Functionality (when
UseDCs = true):has_var<TT, true>(tt, i): Determines whether the function is independent of the i-th variable under some assignment of don't cares.has_var_inplace<TT, true>(tt, i): Same as has_var, but additionally performs the don't care assignment directly in tt.min_base_inplace<TT, true>(tt): Attempts to minimize the function’s support, reassigning don't cares as needed to enforce independence from certain variables.Reassigning don't cares is crucial to ensure consistency across multiple variable checks and to avoid contradictions arising from incompatible don't care assignments.