Question

我正在尝试使用sympy solve解决一个长方程。这是等式的简化版本，但问题是相同的。

此代码可以正常工作：

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import numpy as np import sympy as sy coupons = [0.504452818664, 0.486892427806, 0.47758800215, 100.468050176] rate = sy.Symbol('rate') rate_final = (sy.solve(100 - (rate*coupons[0]+rate*coupons[1]+rate*coupons[2]+rate*coupons[3]),rate)) print rate_final是rate-final。

但是当Ι尝试在等式中使用[0.980998226948197]时，它会给出一个空列表作为结果。

numpy.dot

import numpy as np import sympy as sy coupons = [0.504452818664, 0.486892427806, 0.47758800215, 100.468050176] rate = sy.Symbol('rate') rate_final = (sy.solve(100 - np.dot(rate,coupons[:]),rate)) print rate_final是rate_final。

我的代码是否有问题，如果[]在等式中，sympy.solve将无效？

Answer 1

标量rate和向量coupons的点积几乎没有意义。您只能获得rate和每个元素的元素乘法。但是，您可以这样做：

import numpy as np
import sympy as sy

coupons = np.array([0.504452818664, 0.486892427806, 0.47758800215, 100.468050176])

rate = sy.Symbol('rate')
rate_final = sy.solve(100 - np.sum(rate * coupons), rate)
print(rate_final)

使用sympy solver和numpy dot不起作用

1 个答案: