显示在cvxopt

Question

最佳解是否有不脱离如示于下面的例子显示了迭代值如pcost，dcost，间隙等只显示在cvxopt的最佳值的方式，

n = 5 #no. of design variables 
P = spmatrix(1,range(n),range(n)) 
q = matrix([[60.341,13.05,1.217,5.5,24.2]]) 
m = matrix([[0,0,-2.778,-0.002657,0,0.3004,0],[0.6168,0,0,-0.0005693,0,0.06217,0],[0,5,0,0,0,0,0],[-0.8987,0,0,0,-0.000462,0,0.1554],[0,0,3.33,0,-0.001943,0,0.683]]) 
nl = spmatrix(-1,range(n),range(n)) 
nu = spmatrix(1,range(n),range(n)) 
G = matrix([m,nl,nu]) 
h = matrix([0.0113,1,0.167,0.20289,0.5129,0.9098,0.829,0.05,0.45,0,0.35,0,0.1,1.55,10,1.4,0.15]) 
qp = solvers.qp(P,q,G,h) 
print qp['x'] 

输出：

pcost  dcost  gap pres dres 
0: -1.0569e+03 -4.5953e+02 3e+03 6e+00 2e+00 
1: -1.1312e+02 -1.5294e+02 6e+02 8e-01 2e-01 
2: -1.8148e-01 -5.6851e+01 6e+01 2e-16 7e-15 
3: -6.5682e+00 -1.6549e+01 1e+01 9e-17 7e-16 
4: -1.0162e+01 -1.1053e+01 9e-01 3e-16 2e-16 
5: -1.0470e+01 -1.0624e+01 2e-01 6e-17 3e-16 
6: -1.0502e+01 -1.0506e+01 4e-03 1e-16 4e-16 
7: -1.0503e+01 -1.0503e+01 4e-05 7e-17 2e-16 
8: -1.0503e+01 -1.0503e+01 4e-07 1e-16 2e-16 
Optimal solution found. 
[-5.00e-02] 
[-4.50e-01] 
[ 1.97e-08] 
[-3.21e-01] 
[ 7.81e-10] 

我想仅打印最后5个输出值。

Answer 1

只需关闭详细模式（在cvxopt中调用show_progress）as explained in the docs。

from cvxopt import spmatrix, matrix, solvers 
solvers.options['show_progress'] = False  # !!! 

n = 5 #no. of design variables 
P = spmatrix(1,range(n),range(n)) 
q = matrix([[60.341,13.05,1.217,5.5,24.2]]) 
m = matrix([[0,0,-2.778,-0.002657,0,0.3004,0], 
[0.6168,0,0,-0.0005693,0,0.06217,0],[0,5,0,0,0,0,0], 
[-0.8987,0,0,0,-0.000462,0,0.1554],[0,0,3.33,0,-0.001943,0,0.683]]) 
nl = spmatrix(-1,range(n),range(n)) 
nu = spmatrix(1,range(n),range(n)) 
G = matrix([m,nl,nu]) 
h = matrix([0.0113,1,0.167,0.20289,0.5129,0.9098,0.829,0.05,0.45,0,0.35,0,0.1,1.55,10,1.4,0.15]) 
qp = solvers.qp(P,q,G,h) 
print(qp['x']) 

输出：

[-5.00e-02] 
[-4.50e-01] 
[ 1.97e-08] 
[-3.21e-01] 
[ 7.81e-10]