Package 'Unitary'

Add Gate to Quantum Circuit

Description

It accepts a gate name, a gate object constructed by set_gate(), or a reusable gate adder function.

Usage

add_gate(
  circuit,
  gate,
  targets = NULL,
  controls = integer(0),
  step = NULL,
  ...
)

Arguments

circuit	A qcircuit object.
gate	Gate adder or gate label.
targets	Target qubit indices.
controls	Control qubit indices.
step	Optional insertion step index.
...	Parameter passed to set_gate. When gate is a character of length one, set_gate(target_label=gate, ...) is called to build a gate adder.

Value

A modified qcircuit object.

See Also

set_gate

---

Circuit Layout

Description

Build circuit layout of qubit object.

Usage

build_circuit_layout(qubits, steps)

Arguments

qubits	A qubit object.
steps	Steps.

Value

Layout object.

---

Common Single-qubit Gate Constructors and Wrapped Gates

Description

• set_gate() builds a reusable gate descriptor that contains drawing parameters and prebuilt grobs. The returned object can be inspected or applied to a qcircuit via the returned adder function.

• ⁠gate_*()⁠ create reusable gate adders for common gates and forward their arguments to set_gate().

Usage

set_gate(
  target_label = character(),
  target_label_col = "black",
  target_label_gpar = grid::gpar(col = target_label_col, cex = 2),
  target_shape = "roundrect",
  target_col = "black",
  target_fill = "white",
  target_gpar = grid::gpar(col = target_col, fill = target_fill, lwd = 2),
  control_label = character(),
  control_label_col = "black",
  control_label_gpar = grid::gpar(col = control_label_col, cex = 2),
  control_shape = "dot",
  control_col = "black",
  control_fill = "black",
  control_gpar = grid::gpar(col = control_col, fill = control_fill, lwd = 2),
  gate_label = character(),
  gate_label_col = "black",
  gate_label_gpar = grid::gpar(col = gate_label_col, cex = 1.5),
  targets = NULL,
  controls = integer(0),
  wire_lwd = NA_real_,
  wire_gpar = grid::gpar(col = "black", lwd = wire_lwd),
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 0, ncol =
    0)),
  ...
)

Arguments

target_label	Label displayed inside the gate box.
target_label_col	Text color.
target_label_gpar	grid::gpar used for label text appearance.
target_shape	Target foreground style: one of "roundrect", "rect", "circle", "dot", or "x" (cross).
target_col	Border color.
target_fill	Background fill color.
target_gpar	grid::gpar used to draw target shapes (if gate_gpar is provided it will be used as default).
control_label	Label displayed inside the gate box.
control_label_col	Text color.
control_label_gpar	grid::gpar used for label text appearance.
control_shape	Control decoration style: one of "circle", "rect", "roundrect", "dot", or "x" (cross).
control_col	Border color.
control_fill	Fill color.
control_gpar	grid::gpar used to draw control shapes.
gate_label	Label displayed above the gate box.
gate_label_col	Text color.
gate_label_gpar	grid::gpar used for label text appearance.
targets	Optional preset target indices; if provided the returned adder will have these targets attached as attributes.
controls	Optional preset control indices; if provided the returned adder will have these controls attached as attributes.
wire_lwd	Line width for wires connecting controls and targets.
wire_gpar	grid::gpar used to draw wire between target and control dots.
unitary	A list describing the gate's unitary (should contain f and U).
...	Additional parameters passed to target or control graphical objects, including dot: pch; see points. dot, x and oplus: size. circle: radius. rect or roundrect: ⁠height, width⁠.

Value

A qgate_adder function with attribute gate (the descriptor). The adder has signature adder(circuit, targets, controls, step = NULL).

---

Plot Quantum Circuit

Description

Plot a quantum circuit.

Usage

## S3 method for class 'qcircuit'
plot(x, ...)

Arguments

x	A qcircuit object.
...	Further arguments.

Value

A gtable object invisibly.

Examples

c <- qcircuit(3) |>
     add_gate("H", targets = 1) |>
     add_gate("CNOT", targets = 2, controls = 1) |>
     add_gate("SWAP", targets = c(2, 3))
plot(c)

# example with custom gate gpar
gp <- grid::gpar(fill = "pink", col = "purple")
h2 <- set_gate("H", targets = 1, target_gpar = gp)
c <- qcircuit(2)
c <- h2(c)
plot(c)

---

Print Quantum Circuit Summary and Layout Information

Description

Print Quantum Circuit Summary and Layout Information

Usage

## S3 method for class 'qcircuit'
print(x, layout = FALSE, ...)

Arguments

x	A qcircuit object.
layout	If TRUE, prints detailed gtable structure information of circuit layout.
...	Unused arguments.

Value

The original circuit object invisibly.

Examples

c <- qcircuit(2)
c <- add_gate(c, "H", targets = 1)
print(c, layout = TRUE)

---

Create Quantum Circuit Container

Description

A circuit stores a qubit set and an ordered sequence of gate operations. The internal layout is implemented as a gtable for later rendering.

Usage

qcircuit(n = NULL, qubits = NULL, ...)

is_qcircuit(x)

Arguments

n	Number of qubits in the circuit.
qubits	A qubits object created by set_qubits.
...	Optional arguments for set_qubits.
x	A circuit object.

Value

• qcircuit returns a qcircuit object.

• is_qcircuit returns a bool value.

Examples

c <- qcircuit(4) |>
     gate_cnot(targets = 4, controls = 1) |>
     gate_cnot(targets = 4, controls = 2) |>
     gate_cnot(targets = 4, controls = 3) |>
     add_gate("X", targets = 4, controls = 1) |>
     add_gate("X", targets = 3, target_gpar = grid::gpar(fill="gold2"))
plot(c)

c <- gate_swap(c, targets = 3:4,
                 gate_label = "Phi",
                 gate_label_gpar=grid::gpar(col="red", cex=3),
                 wire_gpar = grid::gpar(col="blue", lwd=3))
plot(c)

c <- gate_toffoli(c, 3, c(2, 4))
plot(c)

c <- gate_cz(c, 4, 2,
             target_label = "e^{-i \\pi Z}",
             control_gpar = grid::gpar(fill="blue", col="blue"),
             wire_gpar = grid::gpar(col="blue", lwd=3))
plot(c)

gate_eg <- set_gate(
     "e^{-i \\pi Z}",
     target_gpar = grid::gpar(fill = "lightgreen", col = "darkgreen"),
     wire_gpar = grid::gpar(lwd=0)
)
c <- gate_eg(c, targets = 2:3)
plot(c)

c <- add_gate(c, "\\int f(x) dx", targets=3, step=9,
                 target_shape = "circle",
                 target_gpar = grid::gpar(fill="lightblue", col="darkblue"),
                 target_label_gpar = grid::gpar(col="red", cex=1.0))
plot(c)

---

Common Single-qubit Gate Constructors and Wrapped Gates

Description

Common Single-qubit Gate Constructors and Wrapped Gates

Usage

gate_h(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_x(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_y(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_z(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_s(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_t(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_i(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 2, ncol =
    2)),
  ...
)

gate_swap(
  circuit,
  targets,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 4, ncol =
    4)),
  ...
)

gate_cnot(
  circuit,
  targets,
  controls,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 4, ncol =
    4)),
  ...
)

gate_cz(
  circuit,
  targets,
  controls,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 4, ncol =
    4)),
  ...
)

gate_toffoli(
  circuit,
  targets,
  controls,
  step = NULL,
  unitary = list(f = function() {
     NULL
 }, U = matrix(complex(), nrow = 8, ncol =
    8)),
  ...
)

Arguments

circuit	A qcircuit object.
targets	Target qubit indices.
step	Optional insertion step index.
unitary	See set_gate.
...	Additional parameters passed to set_gate.
controls	Control qubit indices (for multi-qubit gates).

Details

SWAP gate operates on two target qubits and no explicit controls

gate_cnot: CX gate

gate_cz: CZ gate

Toffoli: CCNOT or CCX gate

Value

A modified qcircuit object.

---

Create Single Qubit Description

Description

This helper is useful when building qubit sets programmatically.

Usage

set_qubit(
  qubits,
  index = NULL,
  name = NULL,
  label = NULL,
  value = NULL,
  label_col = "black",
  label_size = 10,
  wire_col = "grey40",
  label_gpar = grid::gpar(col = label_col, fontsize = label_size),
  wire_gpar = grid::gpar(col = wire_col, lwd = 1)
)

Arguments

qubits	A qubits object to update.
index	Qubit index.
name	Qubit name.
label	Text label for the qubit.
value	Optional value to set for the selected qubit (complex or length 1 numeric).
label_col	Label text color (convenience).
label_size	Label font size (convenience).
wire_col	Wire color (convenience).
label_gpar	Optional grid::gpar to control label appearance (overrides label_col/label_size).
wire_gpar	Optional grid::gpar to control wire appearance (overrides wire_col).

Value

A qubit object.

Examples

qubits <- set_qubits(2)
qubits <- set_qubit(qubits, index = 1, label = "|1>",
                    label_gpar = grid::gpar(col = "red"))

---

Create Qubit Set

Description

set_qubits() defines the qubit names, labels and visual styles for the circuit wires.

Usage

set_qubits(
  n,
  labels = NULL,
  names = NULL,
  values = complex(),
  label_col = "black",
  label_size = 1.5,
  wire_col = "grey40",
  label_gpar = grid::gpar(col = label_col, cex = label_size),
  wire_gpar = grid::gpar(col = wire_col, lwd = 2)
)

Arguments

n	Number of qubits.
labels	Optional labels for each qubit.
names	Optional names for each qubit.
values	States of qubits.
label_col	Label text color (convenience).
label_size	Label font size (convenience).
wire_col	Wire color (convenience).
label_gpar	Optional grid::gpar to control label appearance (overrides label_col/label_size).
wire_gpar	Optional grid::gpar to control wire appearance (overrides wire_col).

Value

A qubits object.

Examples

# create qubits with default appearance
q <- set_qubits(2, labels = c("0", "1"))

# create qubits with explicit gpar for labels and wire
q2 <- set_qubits(3, labels = c("0", "1", "0"),
                  label_gpar = grid::gpar(col = "blue", fontsize = 12),
                  wire_gpar = grid::gpar(col = "grey60", lwd = 2))

---

Validate Qubits

Description

Validate qubits.

Usage

validate_qubits(qubits)

Arguments

qubits

A qubits object.

Value

qubits object.

---