python - CVXOPT QP 求解器 : TypeError: 'A' must be a 'd' matrix with 1000 columns

Question

我正在尝试使用 CVXOPT qp 求解器计算支持向量机的拉格朗日乘数

def svm(X, Y, c):
      m = len(X)
      P = matrix(np.dot(Y, Y.T) * np.dot(X, X.T))
      q = matrix(np.ones(m) * -1)
      g1 = np.asarray(np.diag(np.ones(m) * -1))
      g2 = np.asarray(np.diag(np.ones(m)))
      G = matrix(np.append(g1, g2, axis=0))
      h = matrix(np.append(np.zeros(m), (np.ones(m) * c), axis =0))
      A = np.reshape((Y.T), (1,m))
      b = matrix([0])

      print (A).shape

      A = matrix(A)

      sol = solvers.qp(P, q, G, h, A, b)
      print sol

在这里X是 1000 X 2矩阵和Y具有相同数量的标签。求解器抛出以下错误: $ python svm.py
(1, 1000)
Traceback (most recent call last):
File "svm.py", line 35, in <module>
svm(X, Y, 50)
File "svm.py", line 29, in svm
sol = solvers.qp(P, q, G, h, A, b)
File "/usr/local/lib/python2.7/site-packages/cvxopt/coneprog.py", line 4468, in qp
return coneqp(P, q, G, h, None, A, b, initvals, options = options)
File "/usr/local/lib/python2.7/site-packages/cvxopt/coneprog.py", line 1914, in coneqp
%q.size[0])
TypeError: 'A' must be a 'd' matrix with 1000 columns

我打印了 A 的形状，它是一个 (1,1000)从向量 reshape 后的矩阵。究竟是什么导致了这个错误？

Answer 1

您的矩阵元素也必须是浮点类型。因此，通过使用 A = A.astype('float') 强制转换它来消除错误。