from __future__ import annotations
import warnings
import gdsfactory as gf
from gdsfactory.component import Component
from gdsfactory.components.bend_euler import bend_euler180
from gdsfactory.components.straight import straight
from gdsfactory.typings import ComponentSpec, CrossSectionSpec
diagram = r"""
| length0 |
>---------\
\bend180.info['length']
/
|-------------------/
|
|------------------->------->|
length2
| delta_length | |
"""
[docs]
@gf.cell
def delay_snake3(
length: float = 1600.0,
length0: float = 0.0,
length2: float = 0.0,
n: int = 2,
bend180: ComponentSpec = bend_euler180,
cross_section: CrossSectionSpec = "xs_sc",
**kwargs,
) -> Component:
r"""Returns Snake with a starting bend and 180 bends.
Args:
length: total length.
length0: start length.
length2: end length.
n: number of loops.
bend180: ubend spec.
cross_section: cross_section spec.
kwargs: cross_section settings.
.. code::
| length0 |
>---------\
\bend180.info['length']
/
|-------------------/
|
|------------------->------->|
length2
| delta_length | |
"""
if n % 2:
warnings.warn(f"rounding {n} to {n//2 *2}", stacklevel=3)
n = n // 2 * 2
bend180 = gf.get_component(bend180, cross_section=cross_section, **kwargs)
delta_length = (length - length0 - length2 - n * bend180.info["length"]) / n
if delta_length < 0:
raise ValueError(
"Snake is too short: either reduce length0, length2, "
f"increase the total length, or decrease the number of loops (n = {n}). "
f"delta_length = {int(delta_length)}\n" + diagram
)
s0 = straight(cross_section=cross_section, length=length0, **kwargs)
sd = straight(cross_section=cross_section, length=delta_length, **kwargs)
s2 = straight(cross_section=cross_section, length=length2, **kwargs)
symbol_to_component = {
"_": (s0, "o1", "o2"),
"-": (sd, "o1", "o2"),
")": (bend180, "o2", "o1"),
"(": (bend180, "o1", "o2"),
".": (s2, "o1", "o2"),
}
sequence = "_)" + n // 2 * "-(-)"
sequence = f"{sequence[:-1]}."
return gf.components.component_sequence(
sequence=sequence, symbol_to_component=symbol_to_component
)
def test_length_delay_snake3() -> None:
import numpy as np
length = 200.0
c = delay_snake3(n=2, length=length, length0=50, cross_section="xs_sc")
length_computed = c.area() / 0.5
np.isclose(length, length_computed)
if __name__ == "__main__":
# c = test_delay_snake3_length()
import numpy as np
length = 1562
c = delay_snake3(
n=2,
length=length,
length2=length - 120,
cross_section="xs_sc",
)
length_computed = c.area() / 0.5
assert np.isclose(length, length_computed), length_computed
c.show(show_ports=True)
