Merge pull request #1468 from BenHBLiu/develop

update

fealpy/opt/chaos.py

@@ -0,0 +1,99 @@
+from fealpy.backend import backend_manager as bm
+
+def Logistic(pop_size, dim, miu=4):
+    rand = bm.random.rand(pop_size, dim)
+    for i in range(1, dim):
+        rand[:, i] = miu * rand[:, i - 1] * (1 - rand[:, i - 1])
+    return rand
+
+def Tent(pop_size, dim, tent=1.1):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+        mask = rand[:, j - 1] < tent
+        rand[:, j] = bm.where(mask, rand[:, j - 1] / tent, (1 - rand[:, j - 1]) / (1 - tent))
+
+def Cubic(pop_size, dim):
+    rand = bm.random.rand(pop_size, dim)
+    cubic = 1
+    for j in range(1, dim):
+        rand[:, j] = cubic * rand[:, j - 1] * (1 - rand[:, j - 1] ** 2)
+    return rand 
+
+def Chebyshev(pop_size, dim, chebyshev=4):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+        rand[:, j] = bm.cos(chebyshev * bm.arccos(rand[:, j - 1]))
+    return rand
+
+def Piecewise(pop_size, dim, p=1):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+        prev_col = rand[:, j - 1]
+        cond1 = (0 < prev_col) & (prev_col < p)
+        cond2 = (p <= prev_col) & (prev_col < 0.5)
+        cond3 = (0.5 <= prev_col) & (prev_col < 1 - p)
+        cond4 = (1 - p <= prev_col) & (prev_col < 1)
+        rand[:, j] = bm.where(cond1, prev_col / p,
+                        bm.where(cond2, (prev_col - p) / (0.5 - p),
+                        bm.where(cond3, (1 - p - prev_col) / (0.5 - p),
+                        bm.where(cond4, (1 - prev_col) / p, rand[:, j]))))
+    return rand
+
+def Sinusoidal(pop_size, dim, sinusoidal=2):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+        rand[:, j] = sinusoidal * rand[:, j - 1] ** 2 * bm.sin(bm.pi * rand[:, j - 1])
+    return rand
+
+def Icmic(pop_size, dim ,icmic=2):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+            rand[:, j] = bm.sin(icmic / rand[:, j - 1])
+    return rand
+
+def Bernouli(pop_size, dim, lammda=0.4):
+    rand = bm.random.rand(pop_size, dim)
+    prev_col = rand[:, :-1]
+    condition = prev_col < (1 - lammda)
+    rand[:, 1:] = bm.where(
+        condition,
+        prev_col / (1 - lammda), 
+        (prev_col - 1 + lammda) / lammda
+    )   
+
+def Sine(pop_size, dim, alpha=1, beta=1):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+        rand[:, j] =alpha * bm.sin(beta * rand[:, j - 1])
+    return rand
+
+def Circle(pop_size, dim, a=0.5, b=0.6):
+    rand = bm.random.rand(pop_size, dim)
+    for j in range(1, dim):
+            rand[:, j] = (rand[:, j -1] + a - b / (2 * bm.pi) * bm.sin(2 * bm.pi * rand[:, j - 1])) % 1
+    return rand
+
+
+def initialize(pop_size, dim, ub, lb, method=None):
+
+    pop = bm.zeros([pop_size, dim])
+    if method == None:
+        rand = bm.random.rand(pop_size, dim)
+    else:
+        rand = method(pop_size, dim)
+
+    if isinstance(ub, (float, int)):
+            pop = lb + rand * (ub - lb)
+    else:
+        for i in range(dim):
+            pop[:, i] = rand[:, i] * (ub[i] - lb[i]) + lb[i]    
+
+    return pop
+
+
+
+if __name__ == "__main__":
+    lb = [-1.5, -0.5]
+    ub = [1.5, 2.5]
+    x0 = initialize(5, 2, 1, 2, method=Cubic)
+    print(x0)