‘qtensor’ Dialect

The QTensor dialect for one-dimensional tensors of qubits with linear typing.

The QTensor dialect is an adjusted variant of the standard tensor dialect of MLIR that supports linear typing for one-dimensional tensors of qubits. In order to support linear typing, the extract operations of this dialect are modified so that they also return the updated tensor. In addition, alloc/dealloc operations are added to the dialect to support the bulk allocation and deallocation of qubit tensors with linear types.

Operations

qtensor.alloc (qtensor::AllocOp)

Tensor alloc operation

Syntax:

operation ::= `qtensor.alloc` `(`$size`)` attr-dict `:` type($result)

Allocates a one-dimensional qubit tensor with the given size and returns the allocated tensor. The qubits are initialized to the |0> state. If the size is a constant the resulting tensor has a static size, otherwise the tensor has a dynamic size.

Example:

%qtensor = qtensor.alloc(%c3) : tensor<3x!qco.qubit>

Interfaces: MemoryEffectOpInterface (MemoryEffectOpInterface)

Effects: MemoryEffects::Effect{MemoryEffects::Allocate on ::mlir::SideEffects::DefaultResource}

Operands:

Operand	Description
size	index

Results:

Result	Description
result	1D tensor of QCO qubit value type values

qtensor.dealloc (qtensor::DeallocOp)

Deallocate a tensor

Syntax:

operation ::= `qtensor.dealloc` $tensor attr-dict `:` type($tensor)

This operation deallocates the tensor and the values it holds, releasing its resources. Qubits that were extracted but not inserted again need to be deallocated separately.

Example:

qtensor.dealloc %tensor : tensor<3x!qco.qubit>

Interfaces: MemoryEffectOpInterface (MemoryEffectOpInterface)

Effects: MemoryEffects::Effect{MemoryEffects::Free on ::mlir::SideEffects::DefaultResource}

Operands:

Operand	Description
tensor	1D tensor of QCO qubit value type values

qtensor.extract (qtensor::ExtractOp)

Extract element from tensor

Syntax:

operation ::= `qtensor.extract` $tensor `[` $index `]` attr-dict `:` type($tensor)

The qtensor.extract operation is the modified version of the standard tensor.extract operation of the tensor dialect. It reads a ranked tensor and returns one qubit from the input tensor at the given index. In addition, it also returns the updated input tensor as a result.

Example:

%outTensor, %q0 = qtensor.extract %tensor[%c0] : tensor<4x!qco.qubit>

Traits: AlwaysSpeculatableImplTrait

Interfaces: ConditionallySpeculatable, InferTypeOpInterface, NoMemoryEffect (MemoryEffectOpInterface)

Effects: MemoryEffects::Effect{}

Operands:

Operand	Description
tensor	1D tensor of QCO qubit value type values
index	index

Results:

Result	Description
out_tensor	1D tensor of QCO qubit value type values
result	QCO qubit value type

qtensor.from_elements (qtensor::FromElementsOp)

Create a tensor from a range of values

Syntax:

operation ::= `qtensor.from_elements` $elements attr-dict `:` type($result)

The qtensor.from_elements operation is a wrapper operation of the tensor.from_elements operation. This operation creates a one-dimensional qubit tensor using the operands as its input. This also causes the input qubits to be consumed.

Example:

%tensor = qtensor.from_elements %q0, %q1, %q2 : tensor<3x!qco.qubit>

Traits: AlwaysSpeculatableImplTrait

Interfaces: ConditionallySpeculatable, NoMemoryEffect (MemoryEffectOpInterface)

Effects: MemoryEffects::Effect{}

Operands:

Operand	Description
elements	variadic of QCO qubit value type

Results:

Result	Description
result	Tensor must be statically shaped and elements must be of qubit type

qtensor.insert (qtensor::InsertOp)

Insert element into tensor

Syntax:

operation ::= `qtensor.insert` $scalar `into` $dest `[` $index `]` attr-dict `:` type($dest)

The qtensor.insert operation is a wrapper operation for the tensor.insert operation of the tensor dialect. This operation inserts a qubit scalar into a ranked tensor as specified by the operation’s index. The insertion consumes the input qubit.

Example:

%newTensor = qtensor.insert %q0 into %tensor[%c0] : tensor<3x!qco.qubit>

Traits: AlwaysSpeculatableImplTrait

Interfaces: ConditionallySpeculatable, InferTypeOpInterface, NoMemoryEffect (MemoryEffectOpInterface)

Effects: MemoryEffects::Effect{}

Operands:

Operand	Description
scalar	QCO qubit value type
dest	1D tensor of QCO qubit value type values
index	index

Results:

Result	Description
result	1D tensor of QCO qubit value type values