From b9d1d3cf1f24c83c2375285d55f04fafbf03a097 Mon Sep 17 00:00:00 2001
From: "vn.py" <vn.py@foxmail.com>
Date: Thu, 1 Feb 2018 16:44:35 +0800
Subject: [PATCH] [Fix]Close #706

---
 vnpy/pricing/crr.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/vnpy/pricing/crr.py b/vnpy/pricing/crr.py
index ccb0b8e8..41d381c4 100644
--- a/vnpy/pricing/crr.py
+++ b/vnpy/pricing/crr.py
@@ -139,9 +139,9 @@ def calculateImpv(price, f, k, r, t, cp, n=15):
     # 检查期权价格是否满足最小价值（即到期行权价值）
     meet = False
     
-    if cp == 1 and (price > (f - k) * exp(-r * t)):
+    if cp == 1 and (price > f - k):
         meet = True
-    elif cp == -1 and (price > k * exp(-r * t) - f):
+    elif cp == -1 and (price > k - f):
         meet = True
     
     # 若不满足最小价值，则直接返回0