增加模块；增加主调用命令

prosail_method/modules/dcum.py

@@ -0,0 +1,29 @@
+import numpy as np
+
+def dcum(a, b, t):
+    """
+    计算 PROSAIL 中使用的累积分布函数 dcum
+    
+    Parameters:
+    - a: float
+    - b: float
+    - t: float, in degrees
+
+    Returns:
+    - f: float
+    """
+    rd = np.pi / 180  # degree to radian
+    if a >= 1:
+        f = 1 - np.cos(rd * t)
+    else:
+        eps = 1e-8
+        x = 2 * rd * t
+        p = x
+        delx = 1.0
+        while delx >= eps:
+            y = a * np.sin(x) + 0.5 * b * np.sin(2 * x)
+            dx = 0.5 * (y - x + p)
+            x += dx
+            delx = abs(dx)
+        f = (2 * y + p) / np.pi
+    return f