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我目前的工作在Python中的约束优化问题,而我能够制定我的问题,我得到以下错误:“在LSQ子问题奇异矩阵C”。蟒蛇 - 优化与真/假限制
我相信这是因为我的两个约束(平等)是不连续的或别的东西,涉及到他们,因为优化工作没有他们。
一个例子如下所示:
vol_tgt = 0.1
sign_vec =
---------------+----+
| XLK US Equity | 1 |
| XOP US Equity | 1 |
| KRE US Equity | 1 |
| KBE US EQUITY | 1 |
| XLK US EQUITY | 1 |
| XLE US EQUITY | 1 |
| XLF US EQUITY | 1 |
| XRT US EQUITY | 1 |
| XLU US EQUITY | 1 |
| XLY US EQUITY | 1 |
| XLV US EQUITY | 1 |
| STS FP EQUITY | 1 |
| STR FP EQUITY | 1 |
| STZ FP EQUITY | 1 |
| STW FP EQUITY | 1 |
| STQ FP EQUITY | 1 |
| STN FP EQUITY | -1 |
+---------------+----+
return_vec =
+---------------+--------------+
| XLK US Equity | 0.005951589 |
| XOP US Equity | 0.024262624 |
| KRE US Equity | 0.007112154 |
| KBE US EQUITY | 0.003097968 |
| XLK US EQUITY | 0.005951589 |
| XLE US EQUITY | 0.019948716 |
| XLF US EQUITY | 0.003813095 |
| XRT US EQUITY | -0.001202198 |
| XLU US EQUITY | 0.003021156 |
| XLY US EQUITY | 0.002821742 |
| XLV US EQUITY | 0.004961415 |
| STS FP EQUITY | 0.000827929 |
| STR FP EQUITY | 0.005422823 |
| STZ FP EQUITY | -0.003453351 |
| STW FP EQUITY | -0.001449392 |
| STQ FP EQUITY | 0.015776843 |
| STN FP EQUITY | 0.000937061 |
+---------------+--------------+
的代码如下:
### define necessary functions ###
def optimization_function(weights,returns , vol_tgt, signs) :
return - np.sum(np.log(np.abs(weights))) #multiply by -1 since we wish to maximize but we give the problem
#to a minimizer
def portfolio_vol(weights,returns , vol_tgt, signs) : # inequality
portf_return = np.dot(weights.T,returns)
return np.sqrt(portf_return) - vol_tgt
def absolute_exposure(weights,returns , vol_tgt, signs) :
return np.sum(np.abs(weights)) - 1
def positive_weights(weights,returns , vol_tgt, signs) :
return float(np.sum(weights[signs == 1] <= 0))
def negative_weights(weights,returns , vol_tgt, signs) :
return float(np.sum(weights[signs == -1] >= 0))
weights = sp.fmin_slsqp(optimization_function,lol,args=(return_vec,vol_tgt,sign_vec,),
ieqcons = [portfolio_vol,],eqcons=[absolute_exposure,positive_weights,])
麻烦的功能是positive_weights和negative_weights。没有他们,我没有问题。有没有办法来解决这个问题?
预先感谢您。
它似乎更自然地代表那些为不等式约束。例如,'return weights [signs == 1] .min()'并且约束它是非负的。 (除非重量0和重量1e-308之间的区别实际上非常重要,在这种情况下,我想你可以在返回之前减去一小部分。) – user2357112
@ user2357112谢谢!很好的思想! –