HGSilveri
commented
5 months ago Hi @lvignoli , thanks for the detailed bug report! Upon further inspection, I believe your code is doing something unwanted.
When you define your register from your layout, your are doing:
positions = np.array([tri_layout.traps_dict[i] for i in sites]) reg = pulser.Register.from_coordinates(positions, labels=labels)
There are two issues with this form:
- The register won't be able to recognize which layout it came from.
Register.from_coordinateshascenter=Trueby default, so your coordinates are being modified to center your register around the origin.
At least on my setup, I find that setting center=False is enough to make the issues disappear. Regardless, creating a register from a layout should always be done through:
reg = tri_layout.define_register(*sites, qubit_ids=labels)If your issues persist after this correction, let me know!
lvignoli
On pulser 0.16.1, I experienced ill-defined DMM maps.
(Specs: MacBookPro 2021 M1, python 3.10.2, pulser 0.16.1)
I have tracked down the issue to the ways the weight map is built:
https://github.com/pasqal-io/Pulser/blob/80cf64078e612aa4daaeca0a662f0b181c5b5700/pulser-core/pulser/register/weight_maps.py#L74-L88
While
matchesis expected to be a single element list, this is not checked. Because there is an equality condition on floating point numbers, it may be the empty list. When it is the empty list, the weight assigned to the qubit in the weight map is 0.0.Relaxing the decimal precision specified with COORD_PRECISION to say, 3, recovers the correct DMM maps. Changing the order of the qubits in the register definition recovers a properly defined DMM (!!).
Here is a minimal example to reproduce the issue. Since the issue comes from comparisons of floats, it may not be reproducible on other devices and architectures.
Code
```python import dataclasses import numpy as np import pulser from pulser.devices._devices import AnalogDevice from pulser.register.special_layouts import TriangularLatticeLayout _dmm = pulser.channels.dmm.DMM( clock_period=4, min_duration=16, max_duration=2**26, mod_bandwidth=8, bottom_detuning=-2 * np.pi * 20, # detuning between 0 and -20 MHz total_bottom_detuning=-2 * np.pi * 2000, # total detuning ) device = dataclasses.replace( AnalogDevice, dmm_objects=(_dmm,), max_sequence_duration=10_000, ) tri_layout = TriangularLatticeLayout(n_traps=100, spacing=5) def define_register_with_detuning_weights(sites, labels, weights): positions = np.array([tri_layout.traps_dict[i] for i in sites]) reg = pulser.Register.from_coordinates(positions, labels=labels) det_map = reg.define_detuning_map(dict(zip(labels, weights))) qubit_weight_map = det_map.get_qubit_weight_map(reg.qubits) # Checks that the actual DMM weight is (almost) equal to the provided one. for qubit_id, expected_weight in zip(labels, weights): try: np.testing.assert_almost_equal(qubit_weight_map[qubit_id], expected_weight) except AssertionError as e: msg = f"qubit {qubit_id}: {e}" print(msg) def main(): print("Test 1") sites = np.array([31, 53, 39, 62, 43, 49, 42, 37, 48, 44, 55, 50]) labels = np.array(["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l"]) weights = np.array([0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]) define_register_with_detuning_weights(sites, labels, weights) print() print("Test 2") # The first 4 items of each lists are put at the end. # These are the 0 weights of the DMM map. sites = np.array([43, 49, 42, 37, 48, 44, 55, 50, 31, 53, 39, 62]) labels = np.array(["e", "f", "g", "h", "i", "j", "k", "l", "a", "b", "c", "d"]) weights = np.array([1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0]) define_register_with_detuning_weights(sites, labels, weights) if __name__ == "__main__": main() ``` Output: ```text Test 1 qubit e: Arrays are not almost equal to 7 decimals ACTUAL: 0.0 DESIRED: 1.0 qubit f: Arrays are not almost equal to 7 decimals ACTUAL: 0.0 DESIRED: 1.0 Test 2 ```