Let's say I have an array like this:
from skopt.space import Space
from skopt.sampler import Lhs
import numpy as np
np.random.seed(42)
rows = 5
cols = 3
dummy = np.zeros((rows, cols))
array([[0., 0., 0.],
[0., 0., 0.],
[0., 0., 0.],
[0., 0., 0.],
[0., 0., 0.]])
and I now would like to use skopt.Lhs.generate to fill certain positions of this array with a 1 whereby I would like to exclude certain positions stored in ignore:
ignore = np.array([
[3, 1],
[4, 1]
])
How would I do this best?
I can do
space = Space([(0, rows - 1), (0, cols - 1)])
lhs = Lhs(criterion="maximin", iterations=1000)
lh = np.array(lhs.generate(space.dimensions, 3))
dummy[lh[:, 0], lh[:, 1]] = 1
which gives
array([[0., 0., 1.],
[1., 0., 0.],
[0., 0., 0.],
[0., 0., 0.],
[0., 1., 0.]])
but as one can see the position 4, 1 is occupied but it shouldn't.
One way could be to put the lhs.generate call inside a while loop and then always checks whether any element is in ignore but I am wondering whether there is a more straightforward solution to this.
Just for completeness, a solution using a while loop could look like this:
from skopt.space import Space
from skopt.sampler import Lhs
import numpy as np
def contains_element(a, b):
return any(li in a for li in b)
np.random.seed(42)
rows = 5
cols = 3
dummy = np.zeros((rows, cols))
ignore = [
[3, 1],
[4, 1]
]
space = Space([(0, rows - 1), (0, cols - 1)])
contains_row = True
while contains_row:
lhs = Lhs(criterion="maximin", iterations=1000)
lh = lhs.generate(space.dimensions, 3)
contains_row = contains_element(lh, ignore)
print(lh)
print(contains_row)
print('-----------------------\n')
lh = np.array(lh)
dummy[lh[:, 0], lh[:, 1]] = 1
print(dummy)
which prints
[[2, 0], [0, 2], [4, 1]]
True
-----------------------
[[2, 0], [1, 2], [4, 1]]
True
-----------------------
[[4, 2], [0, 1], [2, 0]]
False
-----------------------
[[0. 1. 0.]
[0. 0. 0.]
[1. 0. 0.]
[0. 0. 0.]
[0. 0. 1.]]
So, here it takes 3 iterations until positions are found which are not in ignore. If anyone knows a more straightforward solution, please let me know!