20250526

160-11.py

@@ -0,0 +1,34 @@
+def SecantSolve(fx, x0, x1, err=1e-10, N0=100):
+    count = 0
+    print(f"k={count}: x{count}={x0}, f(x{count})={fx(x0)}")
+    count += 1
+    print(f"k={count}: x{count}={x1}, f(x{count})={fx(x1)}")
+    count += 1
+    while abs(x1 - x0) > err or abs(fx(x1)) > err:
+        if fx(x1) == fx(x0):
+            return None,0
+        x2 = x1 - fx(x1) * (x1 - x0) / (fx(x1) - fx(x0))
+        print(f"k={count}: x{count}={x2}, f(x{count})={fx(x2)}")
+        count += 1
+        if count > N0:
+            return None,-1
+        x0 = x1
+        x1 = x2
+    return x2,1
+
+
+if __name__ == "__main__":
+    err = 1e-5
+    N0 = 100
+
+    x0 = 0.3
+    x1 = 0.4
+    fx = lambda x: x**4 - 3*x + 1
+
+    result, status = SecantSolve(fx, x0, x1, err, N0)
+    if status == 1:
+        print(f"fx收敛 解为: {result}")
+    elif status == -1:
+        print("fx不收敛")
+    else:
+        print("分母为0，无法收敛")