def euclidean(A, B):
"""
Euclidean distance function.
See scipi.spatial.distance.cdist()
:Example:
>>> from neurolab import mynp as np
>>> euclidean(np.array([0,0]), np.array([[0,1], [0, 5.5]])).tolist()
[1.0, 5.5]
"""
return np.sqrt(np.sum(np.square(A-B) ,axis=1))
def initnw(layer):
"""
Nguyen-Widrow initialization function
"""
ci = layer.ci
cn = layer.cn
w_fix = 0.7 * cn ** (1. / ci)
w_rand = np.random.rand(cn, ci) * 2 - 1
# Normalize
if ci == 1:
w_rand = w_rand / np.abs(w_rand)
else:
w_rand = w_rand * np.sqrt(1. / np.square(w_rand).sum(axis=1).reshape(cn, 1))
w = w_fix * w_rand
b = np.array([0]) if cn == 1 else w_fix * np.linspace(-1, 1, cn) * np.sign(w[:, 0])
# Scaleble to inp_active
amin, amax = layer.transf.inp_active
amin = -1 if amin == -np.Inf else amin
amax = 1 if amax == np.Inf else amax
x = 0.5 * (amax - amin)
y = 0.5 * (amax + amin)
w = x * w
b = x * b + y
# Scaleble to inp_minmax
minmax = layer.inp_minmax.copy()
minmax[np.isneginf(minmax)] = -1
minmax[np.isinf(minmax)] = 1
x = 2. / (minmax[:, 1] - minmax[:, 0])
y = 1. - minmax[:, 1] * x
w = w * x
b += np.dot(w, y)
layer.np['w'][:] = w
layer.np['b'][:] = b
return
def deriv(self, x, y):
"""
Derivative of transfer function TanSig
"""
return 1.0 - np.square(y)
def __call__(self, e):
v = 0.5 * np.sum(np.square(e))
return v
def __call__(self, e):
N = e.size
v = np.sum(np.square(e)) / N
return v
