LMIterm problem: Error using lmiterm, Complex number, NaN or Inf not allowed in A, B.

Error using lmiterm

Complex number, NaN or Inf not allowed in A, B.

A'*P+PA<0, P>0

P = lmivar(1,[2 1]);
lmiterm([1 1 1 P],A_F',1,'s')
LMI = getlmis
[t,~] = feasp(LMI,[0 0 0 0 1])

From my view, I check the A_F. it is impossible for the upper three problem(Complex number, NaN or inf)

Maybe the P variable is NaN or inf in this problem?

I don't know what is the problem about this.

Answer 1

[Sam Chak]

Hi @Syue-Cian

The code looks okay. Can you show the matrix A_F?

Performing Test #1:

% Test #1
A_F        = eye(2)

A_F = 2×2

1 0 0 1

setlmis([]) 
P          = lmivar(1, [2 1]);
lmiterm([1 1 1 P], A_F', 1, 's')
LMI        = getlmis;
[t, xfeas] = feasp(LMI, [0 0 0 0 1])

t = -8.0837e+08

xfeas = 3×1

1.0e+08 * -4.0419 0 -4.0419

P          = dec2mat(LMI, xfeas, P)

P = 2×2

1.0e+08 * -4.0419 0 0 -4.0419

e          = eig(P)

e = 2×1

1.0e+08 * -4.0419 -4.0419

Performing Test #2:

% Test #2
A_F        = eye(2)*1i

A_F = 
   0.0000 + 1.0000i   0.0000 + 0.0000i
   0.0000 + 0.0000i   0.0000 + 1.0000i

setlmis([]) 
P          = lmivar(1, [2 1]);
lmiterm([1 1 1 P], A_F', 1, 's')

Error using lmiterm
Complex numbers, NaN, or Inf not allowed in A,B

LMI        = getlmis;
[t, xfeas] = feasp(LMI, [0 0 0 0 1])
P          = dec2mat(LMI, xfeas, P)
e          = eig(P)