Build Computations

There are two ways to build logical computations that can be used in tqec:

1. Build the computation interactively with SketchUp.

2. Use the data structures provided by tqec to build the computation programmatically.

In this notebook, we will guide you through both methods.

Use SketchUp

SketchUp is a 3D modeling tool widely used in QEC community to build the spacetime diagram for logical computations. Its user-friendly interface allows you to easily create and manipulate the computation blocks.

Once you make a Trimble account, you may freely use the web version of SketchUp to import a .skp file and create a scene. However, unless you are on a Windows machine, you must either activate a paid license or free trial to export a SketchUp .skp file as a COLLADA .dae file. On Windows, it suffices to use the freeware version SketchUp8.

Users that are not on Windows may fully use tqec via the programmatic construction below. Please notify a developer if you are aware of a way to export a SketchUp scene to a .dae file on Mac OSX or Linux.

The workflow using SketchUp to build computations is as follows:

1. Open the template file in SketchUp.

2. Use the building blocks provided in the template file to build your computation. After you finish building, remove the template blocks from the scene.

3. Save and export the model to .dae file format.

4. Import the computation into tqec using the tqec.read_block_graph_from_dae_file function.

Programmatic Construction

To build more large-scale computations or you cannot have access to SketchUp, you can use the data structures provided by tqec to build the computation programmatically. Currently, tqec provides two data structures to represent computations and you can call the methods on them to build the computation:

1. ZXGraph: A ZX-diagram representation from the ZX-calculus.

2. BlockGraph: An exact correspondence to the spacetime diagram representation that can be built in SketchUp.

They are both represented as graphs internally and can be built by adding nodes and edges to them. Here we show how to build a logical CNOT with both ZXGraph and BlockGraph.

ZXGraph

from tqec import ZXGraph, ZXNode, ZXKind, Position3D

g_zx = ZXGraph("Logical CNOT ZX Graph")
g_zx.add_edge(
    ZXNode(Position3D(0, 0, 0), ZXKind.P, "In_Control"),
    ZXNode(Position3D(0, 0, 1), ZXKind.Z),
)
g_zx.add_edge(
    ZXNode(Position3D(0, 0, 1), ZXKind.Z),
    ZXNode(Position3D(0, 0, 2), ZXKind.X),
)
g_zx.add_edge(
    ZXNode(Position3D(0, 0, 2), ZXKind.X),
    ZXNode(Position3D(0, 0, 3), ZXKind.P, "Out_Control"),
)
g_zx.add_edge(
    ZXNode(Position3D(0, 0, 1), ZXKind.Z),
    ZXNode(Position3D(0, 1, 1), ZXKind.Z),
)
g_zx.add_edge(
    ZXNode(Position3D(0, 1, 1), ZXKind.Z),
    ZXNode(Position3D(0, 1, 2), ZXKind.X),
)
g_zx.add_edge(
    ZXNode(Position3D(0, 1, 2), ZXKind.X),
    ZXNode(Position3D(1, 1, 2), ZXKind.X),
)
g_zx.add_edge(
    ZXNode(Position3D(1, 1, 0), ZXKind.P, "In_Target"),
    ZXNode(Position3D(1, 1, 1), ZXKind.X),
)
g_zx.add_edge(
    ZXNode(Position3D(1, 1, 1), ZXKind.X),
    ZXNode(Position3D(1, 1, 2), ZXKind.X),
)
g_zx.add_edge(
    ZXNode(Position3D(1, 1, 2), ZXKind.X),
    ZXNode(Position3D(1, 1, 3), ZXKind.P, "Out_Target"),
)

g_zx.draw()

(<Figure size 500x600 with 1 Axes>,
 <Axes3D: title={'center': 'Logical CNOT ZX Graph'}>)

BlockGraph

Once you have a ZXGraph, you can try to convert it to a BlockGraph:

g_block_from_zx = g_zx.to_block_graph()

Else, you can build the BlockGraph directly:

from tqec import BlockGraph, Cube, ZXCube, Port

g_block = BlockGraph("Logical CNOT ZX Graph")
g_block.add_edge(
    Cube(Position3D(0, 0, 0), Port(), "In_Control"),
    Cube(Position3D(0, 0, 1), ZXCube.from_str("ZXX")),
)
g_block.add_edge(
    Cube(Position3D(0, 0, 1), ZXCube.from_str("ZXX")),
    Cube(Position3D(0, 0, 2), ZXCube.from_str("ZXZ")),
)
g_block.add_edge(
    Cube(Position3D(0, 0, 2), ZXCube.from_str("ZXZ")),
    Cube(Position3D(0, 0, 3), Port(), "Out_Control"),
)
g_block.add_edge(
    Cube(Position3D(0, 0, 1), ZXCube.from_str("ZXX")),
    Cube(Position3D(0, 1, 1), ZXCube.from_str("ZXX")),
)
g_block.add_edge(
    Cube(Position3D(0, 1, 1), ZXCube.from_str("ZXX")),
    Cube(Position3D(0, 1, 2), ZXCube.from_str("ZXZ")),
)
g_block.add_edge(
    Cube(Position3D(0, 1, 2), ZXCube.from_str("ZXZ")),
    Cube(Position3D(1, 1, 2), ZXCube.from_str("ZXZ")),
)
g_block.add_edge(
    Cube(Position3D(1, 1, 0), Port(), "In_Target"),
    Cube(Position3D(1, 1, 1), ZXCube.from_str("ZXZ")),
)
g_block.add_edge(
    Cube(Position3D(1, 1, 1), ZXCube.from_str("ZXZ")),
    Cube(Position3D(1, 1, 2), ZXCube.from_str("ZXZ")),
)
g_block.add_edge(
    Cube(Position3D(1, 1, 2), ZXCube.from_str("ZXZ")),
    Cube(Position3D(1, 1, 3), Port(), "Out_Target"),
)
g_block.view_as_html()