ERROR: FSOLVE requires all values returned by functions to be of data type double.

I understand FSOLVE does not work with sym variables but it is not working using fzero as well. OR is there any alternative?

function fval = fun(u)
d1=20;
n=10^-11.4;
m=2.7;
a=0.5;
T=1;
PsByN_0dB=25;                                                     
PsByN_0=10.^(PsByN_0dB/10);
fun2 = @(u) ((1./u).*log(expint(2,sym(-PsByN_0.*u))).*exp(-PsByN_0*u));
u0 = -0.0031622776;
U = fsolve(fun2,u0)

I have also tried using fzero:

function fval = fun(u)
d1=20;
n=10^-11.4;
m=2.7;
a=0.5;
T=1;
PsByN_0dB=25;                                                     
PsByN_0=10.^(PsByN_0dB/10);
fun2 = @(u) ((1./u).*log(expint(2,sym(-PsByN_0.*u))).*exp(-PsByN_0*u));
u0 = -0.0031622776;
fzero (fun2, u0)

[Voss]

What is the intention here?

expint(2,sym(-PsByN_0.*u))

[Dhawal Beohar]

thats the expression with Two-Argument Exponential Integral and if I not use sym it is giving a error.

Answer 1

[Walter Roberson]

fun2 = @(u) ((1./u).*log(double(expint(2,sym(-PsByN_0.*u)))).*exp(-PsByN_0*u));

[Dhawal Beohar]

Thanks Walter !