Trying to create an array

So I have this array with 2 conjugate pairs and 1 real value

sp =

-0.0895 + 0.9901i

-0.0895 - 0.9901i

-0.2342 + 0.6119i

-0.2342 - 0.6119i

-0.2895 + 0.0000i

I'm trying to create another array called P(k)

with the 3 equations P1, P2,and P3

The equation for the conjugate pairs is

P(k) = (s - sp1(k)) * (s - sp2(k))

where sp1 is the first complex number of the pair and sp2 is the second complex number of the pair

Ex:

sp1 = -0.0895 + 0.9901i

sp2 = -0.0895 - 0.9901i

The equation for real numbers

P(k) = (s - sp(k))

where sp(k) is that given real value

Ex:

sp = -0.2895 + 0.0000i

The answer is

P = [s^2 + 0.1789s +0.9883,

s^2 +0.4684s +0.4293,

s + 0.2895]

I TRIED THIS:

syms s

Ns = 3

%Complex Roots

X = sp(imag(sp)~=0);

S = isreal(X)

%Real Roots

Y = sp(imag(sp)==0);

T = isreal(Y)

for k = 1:Ns

if T == 0

P(k) = vpa(simplify((s-X(2*k-1))*(s-X(2*k))))

else

P(k) = vpa(simplify(s-Y(k-2)))

end

end

Answer 1

[Star Strider]

Try this:

sp = [
  -0.0895 + 0.9901i
  -0.0895 - 0.9901i
  -0.2342 + 0.6119i
  -0.2342 - 0.6119i
  -0.2895 + 0.0000i];

for k = 1:2:numel(sp)
    ixr = unique(min([1 2]+(k-1),numel(sp)))
    p = poly(sp(ixr))
    if all(p ~= 0)
        ki = ceil(k/2);
        P{ki,:} = p;
    end
end

syms s 
for k = 1:numel(P)
    Ps(k,:) = poly2sym(P{k},s);
end
Ps = vpa(Ps,4) 

producing:

Ps =
  s^2 + 0.179*s + 0.9883
 s^2 + 0.4684*s + 0.4293
              s + 0.2895

.

[Daniel Zalivchi]

Thank you so much

[Star Strider]

As always, my pleasure!