[docs]def gfun_57(x):
"""Performance function for reliability problem 57.
Parameters
----------
x : numpy.array of float(s)
Values of independent variables: columns are the different parameters/random variables (x1, x2,...xn) and rows are different parameter/random variables sets for different calls.
Returns
-------
g_val_sys : numpy.array of float(s)
Performance function value for the system.
g_val_comp : numpy.array of float(s)
Performance function value for each component.
msg : str
Accompanying diagnostic message, e.g. warning.
"""
import numpy as np
# expected number of random variables/columns
nrv_e = 2
g, g1, g2, g3 = float('nan'), float('nan'), float('nan'), float('nan')
msg = 'Ok'
x = np.array(x, dtype='f')
n_dim = len(x.shape)
if n_dim == 1:
x = np.array(x)[np.newaxis]
elif n_dim > 2:
msg = 'Only available for 1D and 2D arrays.'
return float('nan'), float('nan'), msg
nrv_p = x.shape[1]
if nrv_p != nrv_e:
msg = f'The number of random variables (x, columns) is expected to be {nrv_e} but {nrv_p} is provided!'
else:
g1 = -x[:, 0] ** 2 + x[:, 1] ** 3 + 3
g2 = 2 - x[:, 0] - 8 * x[:, 1]
g3 = (x[:, 0] + 3) ** 2 + (x[:, 1] + 3) ** 2 - 4
g = [min(max(g1[i], g2[i]), g3[i]) for i in range(len(g1))]
gmax12 = np.amax(np.stack((g1, g2)), 0)
g = np.amin(np.stack((gmax12, g3)), 0)
g_val_sys = g
g_val_comp = np.stack((g1, g2, g3))
return g_val_sys, g_val_comp, msg