quipper-libraries- The standard libraries for Quipper.

Safe HaskellUnsafe




This module contains an efficient representation of algebraic boolean formulas.


Auxiliary functions

mapOfSet :: Ord a => Set a -> Map a Int Source #

Build the characteristic function of a set.

setOfMap :: Ord a => Map a Int -> Set a Source #

Get the set of elements whose images are odd.

split_even :: [a] -> ([a], [a]) Source #

Split a list in the middle.


type Exp = Set IntSet Source #

The type of algebraic boolean expressions.

We represent boolean expressions using "and" and "xor" as the primitive connectives. Equivalently, we can regard booleans as the elements of the two-element field F2, with operations "*" (times) and "+" (plus).

An algebraic expression x1*x2*x3 + y1*y2*y3 + z1*z2 is encoded as {{x1,x2,x3},{y1,y2,y3},{z1,z2}}.

In particular, {} == False == 0 and {{}} == True == 1.

listOfExp :: Exp -> [[Int]] Source #

Turn an Exp into a list of lists.

expOfList :: [[Int]] -> Exp Source #

Turn a list of lists into an Exp.

exp_and :: Exp -> Exp -> Exp Source #

The conjunction of two expression.

exp_xor :: Exp -> Exp -> Exp Source #

The xor of two expressions.

exp_false :: Exp Source #

The expression "False".

exp_true :: Exp Source #

The expression "True".

exp_not :: Exp -> Exp Source #

The negation of an expression.

exp_var :: Int -> Exp Source #

The expression xn.

Properties of expressions

The important property of expressions is that two formulas have the same truth table iff they are syntactically equal. This makes the equality test of wires theoretically straightforward.

Truth tables

A valuation on a set of variables is a map from variables to booleans. This can be thought of as a row in a truth table. A truth table is a map from valuations to booleans, but we just represent this as a list of booleans, listed in lexicographically increasing order of valuations.

vars_of_exp :: Exp -> [Int] Source #

Get the variables used in an expression.

exp_eval :: Exp -> Map Int Bool -> Bool Source #

Evaluate the expression with respect to the given valuation. A valuation is a map from variables to booleans, i.e., a row in a truth table.

valuations_of_vars :: [Int] -> [Map Int Bool] Source #

Construct the list of all 2n valuations for a given list of n variables.

truth_table_of_exp :: [Int] -> Exp -> [Bool] Source #

Build the truth table for the given expression, on the given list of variables. The truth table is returned as a list of booleans in lexicographic order of valuations. For example, if

 1 2 | exp
 F F | f1
 F T | f2
 T F | f3
 T T | f4

then the output of the function is [f1,f2,f3,f4].

exp_of_truth_table :: Int -> [Bool] -> Exp Source #

Return an expression realizing the given truth table. Uses variables starting with the given number.

Orphan instances

Show Exp Source # 
Instance details


showsPrec :: Int -> Exp -> ShowS #

show :: Exp -> String #

showList :: [Exp] -> ShowS #