qc.draw('text', idle_wires=False) results in ValueError : min() arg is an empty sequence #13128

sumit-kale · 2024-09-11T05:15:38Z

Environment

Qiskit version: 1.2.0
Python version: 3.10.14
Operating system: MacOS (M1)

What is happening?

For a parametrised quantum circuit qc.draw('text', idle_wires=False) results in ValueError: min() arg is an empty sequence
This issue only comes in Qiskit version: 1.2.0 and the same code works fine in Qiskit version: 1.1.0.

Additionally qc.draw('mpl', idle_wires=False) prints the quantum circuit but the number of qubits gets reduced. We haven't trinspiled the circuit yet and didn't mention anything about qubit reuse.

This is the full traceback!

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
File /opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:347, in BaseFormatter.__call__(self, obj)
    [345](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:345)     method = get_real_method(obj, self.print_method)
    [346](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:346)     if method is not None:
--> [347](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:347)         return method()
    [348](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:348)     return None
    [349](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/IPython/core/formatters.py:349) else:

File /opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:762, in TextDrawing._repr_html_(self)
    [755](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:755) def _repr_html_(self):
    [756](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:756)     return (
    [757](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:757)         '<pre style="word-wrap: normal;'
    [758](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:758)         "white-space: pre;"
    [759](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:759)         "background: #fff0;"
    [760](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:760)         "line-height: 1.1;"
    [761](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:761)         'font-family: &quot;Courier New&quot;,Courier,monospace">'
--> [762](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:762)         f"{self.single_string()}</pre>"
    [763](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:763)     )

File /opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:779, in TextDrawing.single_string(self)
    [776](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:776)     return self._single_string
    [777](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:777) try:
    [778](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:778)     self._single_string = (
--> [779](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:779)         "\n".join(self.lines()).encode(self.encoding).decode(self.encoding)
...
-> [1079](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:1079)     if min(qubit_indices) > wire_map[ctrl_qubit[0]]:
   [1080](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:1080)         top_box.append(ctrl_qubit)
   [1081](https://file+.vscode-resource.vscode-cdn.net/opt/miniconda3/envs/qiskitenv/lib/python3.10/site-packages/qiskit/visualization/circuit/text.py:1081)     elif max(qubit_indices) < wire_map[ctrl_qubit[0]]:

ValueError: min() arg is an empty sequence

How can we reproduce the issue?

# Minimal code

from qiskit import QuantumCircuit, ClassicalRegister, QuantumRegister
from qiskit.circuit import ParameterVector
import numpy as np

nx=2

thetas = ParameterVector('θ',length=1)
phis = ParameterVector('φ',length=nx+1)  

qr = QuantumRegister(nx+1)
cr = ClassicalRegister(1)
qc = QuantumCircuit(qr,cr)

for i in range(nx):
    qc.ry(thetas[0], i)
qc.barrier()

for i in range(nx):
    j=nx-i # start from the highest power
    qc.ry(phis[j], j)
    qc.rz(np.pi/2,j-1)
    qc.cx(j-1,j)
            
qc.barrier()
qc.ry(phis[0], 0)  
qc.measure(0, 0)

print(qc.draw('text',idle_wires=False))
print(qc.draw('mpl',idle_wires=False))

What should happen?

The user should be able to print the quantum circuit without getting the ValueError and the circuit with 'mpl' should not reduce the number of qubits.

Any suggestions?

No response

The text was updated successfully, but these errors were encountered:

t-imamichi · 2024-09-13T02:56:17Z

It has been fixed by the main branch already. But the fix is not ported to the latest release 1.2.1, unfortunately.

# main branch

      ┌──────────┐ ░ ┌─────────┐                        ░ ┌──────────┐┌─┐
q0_0: ┤ Ry(θ[0]) ├─░─┤ Rz(π/2) ├────────────────────■───░─┤ Ry(φ[0]) ├┤M├
      ├──────────┤ ░ ├─────────┤      ┌──────────┐┌─┴─┐ ░ └──────────┘└╥┘
q0_1: ┤ Ry(θ[0]) ├─░─┤ Rz(π/2) ├───■──┤ Ry(φ[1]) ├┤ X ├─░──────────────╫─
      └──────────┘ ░ ├─────────┴┐┌─┴─┐└──────────┘└───┘ ░              ║
q0_2: ─────────────░─┤ Ry(φ[2]) ├┤ X ├──────────────────░──────────────╫─
                   ░ └──────────┘└───┘                  ░              ║
c0: 1/═════════════════════════════════════════════════════════════════╩═
                                                                       0

# qiskit 1.2.1

Traceback (most recent call last):
  File "/Users/ima/tasks/4_2024/qiskit/terra/tmp/13128.py", line 30, in <module>
    print(qc.draw('text',idle_wires=False))
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 753, in __str__
    return self.single_string()
           ^^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 779, in single_string
    "\n".join(self.lines()).encode(self.encoding).decode(self.encoding)
              ^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 827, in lines
    layers = self.build_layers()
             ^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 1287, in build_layers
    layer, current_cons, current_cons_cond, connection_label = self._node_to_gate(
                                                               ^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 1181, in _node_to_gate
    controls_array = TextDrawing.controlled_wires(
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ima/envs/qiskit312/lib/python3.12/site-packages/qiskit/visualization/circuit/text.py", line 1079, in controlled_wires
    if min(qubit_indices) > wire_map[ctrl_qubit[0]]:
       ^^^^^^^^^^^^^^^^^^
ValueError: min() iterable argument is empty

Cryoris · 2024-09-13T12:05:07Z

With @mrossinek we had quite the bug hunt for this:

Avoid operator creation in transpiler #12826 introduces this bug on main and 1.2 (since it was backported)
[DAGCircuit Oxidation] Port DAGCircuit to Rust #12550 fixes this on main

After some surgical insertions of print statements it turns out that the DAGCircuit.layers method is the culprit, from what we understood because it adds nodes to a layer via reference instead of a copy, as before.

mrvee-qC-bee · 2024-09-16T05:43:58Z

@kifumi -san for your awareness!

sumit-kale added the bug Something isn't working label Sep 11, 2024

t-imamichi added the mod: visualization qiskit.visualization label Sep 13, 2024

Cryoris mentioned this issue Sep 13, 2024

Fix the text drawer with partially idle wires #13149

Merged

1ucian0 added this to the 1.2.2 milestone Sep 13, 2024

1ucian0 mentioned this issue Sep 13, 2024

qc_compiled.draw(output="mpl",idle_wires=False) collapses to display only 1 qubit for dynamic circuits #13146

Closed

1ucian0 linked a pull request Sep 16, 2024 that will close this issue

Fix the text drawer with partially idle wires #13149

Merged

jakelishman mentioned this issue Sep 17, 2024

Qiskit visualization ignores control qubit as idle_wires when following a barrier. #13171

Closed

jakelishman closed this as completed Sep 17, 2024

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qc.draw('text', idle_wires=False) results in ValueError : min() arg is an empty sequence #13128

qc.draw('text', idle_wires=False) results in ValueError : min() arg is an empty sequence #13128

sumit-kale commented Sep 11, 2024

t-imamichi commented Sep 13, 2024 •

edited

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Cryoris commented Sep 13, 2024 •

edited

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mrvee-qC-bee commented Sep 16, 2024 •

edited

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qc.draw('text', idle_wires=False) results in ValueError : min() arg is an empty sequence #13128

qc.draw('text', idle_wires=False) results in ValueError : min() arg is an empty sequence #13128

Comments

sumit-kale commented Sep 11, 2024

Environment

What is happening?

How can we reproduce the issue?

What should happen?

Any suggestions?

t-imamichi commented Sep 13, 2024 • edited Loading

Cryoris commented Sep 13, 2024 • edited Loading

mrvee-qC-bee commented Sep 16, 2024 • edited Loading

t-imamichi commented Sep 13, 2024 •

edited

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Cryoris commented Sep 13, 2024 •

edited

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mrvee-qC-bee commented Sep 16, 2024 •

edited

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