How do I write functions that modify operations in Q#?
In Q#'s type documentation, it is mentioned that you can create signatures like this:
function ConjugateInvertibleWith : (inner: ((Qubit => Unit) : Adjoint),
outer : ((Qubit => Unit) : Adjoint))
: ((Qubit => Unit) : Adjoint)
My question is: how is this function actually implemented.
Presumably a function with this name will return an operation that, when invoked, calls outer, then inner, then adjoint outer. However, I have no idea how to actually write a function like this. In particular, it's not clear how to write the equivalent of a lambda with a closure. For example, if I try to declare an operation inside a function (similar to how you can def inside a def in python), I get a syntax error.
Does this have to be done in a non-Q# library, like in C#, then imported into Q#? If so, how?
q#
asked 5 hours ago
Craig Gidney
3,479220
add a comment |
In Q#'s type documentation, it is mentioned that you can create signatures like this:
function ConjugateInvertibleWith : (inner: ((Qubit => Unit) : Adjoint),
outer : ((Qubit => Unit) : Adjoint))
: ((Qubit => Unit) : Adjoint)
My question is: how is this function actually implemented.
Presumably a function with this name will return an operation that, when invoked, calls outer, then inner, then adjoint outer. However, I have no idea how to actually write a function like this. In particular, it's not clear how to write the equivalent of a lambda with a closure. For example, if I try to declare an operation inside a function (similar to how you can def inside a def in python), I get a syntax error.
Does this have to be done in a non-Q# library, like in C#, then imported into Q#? If so, how?
q#
asked 5 hours ago
Craig Gidney
3,479220
add a comment |
In Q#'s type documentation, it is mentioned that you can create signatures like this:
function ConjugateInvertibleWith : (inner: ((Qubit => Unit) : Adjoint),
outer : ((Qubit => Unit) : Adjoint))
: ((Qubit => Unit) : Adjoint)
My question is: how is this function actually implemented.
Presumably a function with this name will return an operation that, when invoked, calls outer, then inner, then adjoint outer. However, I have no idea how to actually write a function like this. In particular, it's not clear how to write the equivalent of a lambda with a closure. For example, if I try to declare an operation inside a function (similar to how you can def inside a def in python), I get a syntax error.
Does this have to be done in a non-Q# library, like in C#, then imported into Q#? If so, how?
q#
asked 5 hours ago
Craig Gidney
3,479220
In Q#'s type documentation, it is mentioned that you can create signatures like this:
function ConjugateInvertibleWith : (inner: ((Qubit => Unit) : Adjoint),
outer : ((Qubit => Unit) : Adjoint))
: ((Qubit => Unit) : Adjoint)
My question is: how is this function actually implemented.
Presumably a function with this name will return an operation that, when invoked, calls outer, then inner, then adjoint outer. However, I have no idea how to actually write a function like this. In particular, it's not clear how to write the equivalent of a lambda with a closure. For example, if I try to declare an operation inside a function (similar to how you can def inside a def in python), I get a syntax error.
Does this have to be done in a non-Q# library, like in C#, then imported into Q#? If so, how?
q#
q#
asked 5 hours ago
Craig Gidney
3,479220
asked 5 hours ago
Craig Gidney
3,479220
asked 5 hours ago
Craig Gidney
3,479220
asked 5 hours ago
Craig Gidney
3,479220
asked 5 hours ago
Craig Gidney
3,479220
3,479220
add a comment |
add a comment |
1 Answer
1
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For this example, one obtains a function with that signature by partial application of an operation that is defined outside the body, instead of as a lambda in the function. As a concrete example, consider this non-generic version of the WithA operation, modified from line 73 of Q# canon.
operation WithA(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint),
target : Qubit)
: Unit
{
body (...)
{
outer(target);
inner(target);
Adjoint outer(target);
}
adjoint invert;
}
This applies the sequence $|textrm{target}ranglerightarrowtextrm{outer}^daggercdottextrm{inner}cdottextrm{outer}|textrm{target}rangle$.
We can then partially apply the target to create the desired signature as follows.
function WithAFunction(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint))
: ((Qubit => Unit) : Adjoint)
{
return WithA(outer, inner, _);
}
answered 4 hours ago
Guang Hao Low
1364
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
For this example, one obtains a function with that signature by partial application of an operation that is defined outside the body, instead of as a lambda in the function. As a concrete example, consider this non-generic version of the WithA operation, modified from line 73 of Q# canon.
operation WithA(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint),
target : Qubit)
: Unit
{
body (...)
{
outer(target);
inner(target);
Adjoint outer(target);
}
adjoint invert;
}
This applies the sequence $|textrm{target}ranglerightarrowtextrm{outer}^daggercdottextrm{inner}cdottextrm{outer}|textrm{target}rangle$.
We can then partially apply the target to create the desired signature as follows.
function WithAFunction(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint))
: ((Qubit => Unit) : Adjoint)
{
return WithA(outer, inner, _);
}
answered 4 hours ago
Guang Hao Low
1364
add a comment |
For this example, one obtains a function with that signature by partial application of an operation that is defined outside the body, instead of as a lambda in the function. As a concrete example, consider this non-generic version of the WithA operation, modified from line 73 of Q# canon.
operation WithA(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint),
target : Qubit)
: Unit
{
body (...)
{
outer(target);
inner(target);
Adjoint outer(target);
}
adjoint invert;
}
This applies the sequence $|textrm{target}ranglerightarrowtextrm{outer}^daggercdottextrm{inner}cdottextrm{outer}|textrm{target}rangle$.
We can then partially apply the target to create the desired signature as follows.
function WithAFunction(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint))
: ((Qubit => Unit) : Adjoint)
{
return WithA(outer, inner, _);
}
answered 4 hours ago
Guang Hao Low
1364
add a comment |
For this example, one obtains a function with that signature by partial application of an operation that is defined outside the body, instead of as a lambda in the function. As a concrete example, consider this non-generic version of the WithA operation, modified from line 73 of Q# canon.
operation WithA(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint),
target : Qubit)
: Unit
{
body (...)
{
outer(target);
inner(target);
Adjoint outer(target);
}
adjoint invert;
}
This applies the sequence $|textrm{target}ranglerightarrowtextrm{outer}^daggercdottextrm{inner}cdottextrm{outer}|textrm{target}rangle$.
We can then partially apply the target to create the desired signature as follows.
function WithAFunction(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint))
: ((Qubit => Unit) : Adjoint)
{
return WithA(outer, inner, _);
}
answered 4 hours ago
Guang Hao Low
1364
For this example, one obtains a function with that signature by partial application of an operation that is defined outside the body, instead of as a lambda in the function. As a concrete example, consider this non-generic version of the WithA operation, modified from line 73 of Q# canon.
operation WithA(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint),
target : Qubit)
: Unit
{
body (...)
{
outer(target);
inner(target);
Adjoint outer(target);
}
adjoint invert;
}
This applies the sequence $|textrm{target}ranglerightarrowtextrm{outer}^daggercdottextrm{inner}cdottextrm{outer}|textrm{target}rangle$.
We can then partially apply the target to create the desired signature as follows.
function WithAFunction(
outer : (Qubit => Unit : Adjoint),
inner : (Qubit => Unit : Adjoint))
: ((Qubit => Unit) : Adjoint)
{
return WithA(outer, inner, _);
}
answered 4 hours ago
Guang Hao Low
1364
edited 4 hours ago
answered 4 hours ago
Guang Hao Low
1364
answered 4 hours ago
Guang Hao Low
1364
answered 4 hours ago
Guang Hao Low
1364
1364
add a comment |
add a comment |
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