Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix SBX prob_bin parameter behavior #673

Open
wants to merge 2 commits into
base: develop
Choose a base branch
from
Open

Fix SBX prob_bin parameter behavior #673

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
10d3801
Fix prob_bin behavior
lukepmccombs Dec 21, 2024
ca8370e
Fewer masks
Jan 13, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 7 additions & 8 deletions pymoo/operators/crossover/sbx.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,9 @@ def cross_sbx(X, xl, xu, eta, prob_var, prob_bin, eps=1.0e-14):
cross[:, xl == xu] = False

# assign y1 the smaller and y2 the larger value
y1 = np.min(X, axis=0)[cross]
y2 = np.max(X, axis=0)[cross]
X_cross = X[:, cross]
p1_low = X_cross[0] < X_cross[1]
y1, y2 = np.where(p1_low[None,], X_cross, X_cross[::-1])

# mask all the values that should be crossovered
_xl = np.repeat(xl[None, :], n_matings, axis=0)[cross]
Expand Down Expand Up @@ -61,17 +62,15 @@ def calc_betaq(beta):
c2 = 0.5 * ((y1 + y2) + betaq * delta)

# with the given probability either assign the value from the first or second parent
b = np.random.random(len(prob_bin)) < prob_bin
tmp = np.copy(c1[b])
c1[b] = c2[b]
c2[b] = tmp
b = (np.random.random(len(prob_bin)) < prob_bin) == p1_low
C = np.stack((c1, c2), 0)
C = np.where(b[None,], C, C[::-1])

# first copy the unmodified parents
Q = np.copy(X)

# copy the positions where the crossover was done
Q[0, cross] = c1
Q[1, cross] = c2
Q[:, cross] = C

Q[0] = repair_clamp(Q[0], xl, xu)
Q[1] = repair_clamp(Q[1], xl, xu)
Expand Down