from __future__ import annotations
import warnings
import numpy as np
import gdsfactory as gf
from gdsfactory.component import Component
from gdsfactory.typings import ComponentSpec, CrossSectionSpec
diagram = """
| length0 | length1 |
>---------|
| bend180.length
|-------------------|
|
|------------------->------- |
length2
| delta_length | |
"""
[docs]
@gf.cell
def delay_snake2(
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:
"""Returns Snake with a starting straight and 180 bends.
Input faces west output faces east.
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 | length1 |
>---------|
| bend180.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 + 1)
length1 = delta_length - length0
delta_length = np.round(delta_length, 3)
length1 = np.round(length1, 3)
if length1 < 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"length1 = {int(length1)}, delta_length = {int(delta_length)}\n" + diagram
)
s1 = gf.components.straight(length=length1, cross_section=cross_section, **kwargs)
s2 = gf.components.straight(length=length2, cross_section=cross_section, **kwargs)
sd = gf.components.straight(
cross_section=cross_section, length=delta_length, **kwargs
)
symbol_to_component = {
"_": (s1, "o1", "o2"),
"-": (sd, "o1", "o2"),
")": (bend180, "o2", "o1"),
"(": (bend180, "o1", "o2"),
".": (s2, "o1", "o2"),
}
sequence = "_)" + n // 2 * "-(-)"
sequence = sequence[:-1]
sequence += "."
return gf.components.component_sequence(
sequence=sequence, symbol_to_component=symbol_to_component
)
def test_length_delay_snake2() -> Component:
import numpy as np
length = 200.0
c = delay_snake2(length=length, cross_section="xs_sc")
length_computed = c.area() / 0.5
np.isclose(length, length_computed)
if __name__ == "__main__":
import gdsfactory as gf
# c = test_length_delay_snake2()
# c.show(show_ports=True)
# c = delay_snake2(n=2, length=500, layer=(2, 0), length0=100)
# c = delay_snake2()
# c = gf.grid([gf.c.delay_snake, delay_snake2(length0=100), gf.c.delay_snake3])
c = delay_snake2()
c.show(show_ports=True)
c.assert_ports_on_grid()
