I need help integrating this function

Below is the code. I got error when I tried to integrate Q_total. Below is the error i got

ERROR:

Index exceeds the number of array elements (202).

Error in main (line 95)

Q_total=integral(qtot(w(a)),0,w);

CODE:

for a=1:length(w)

betaevanmax=10/d; %upper limit of the parallel wavevector for evanescent wave integration (see ACS NANO paper method section)

betaevanmin=w(a)/c; %lower limit

%Finding spectral RHF for prop and evan fields

qevan_p(a)=(Theta(w(a), T1,0)-Theta(w(a), T2, V))*1/pi^2*integral(@(beta)sevan_p(w(a),beta, d),betaevanmin,betaevanmax,'Reltol',1E-6,'AbsTol',1E-10); %default abstol = 1E-10 reltol 1E-6

qevan_s(a)=(Theta(w(a), T1,0)-Theta(w(a), T2, V))*1/pi^2*integral(@(beta)sevan_s(w(a),beta, d),betaevanmin,betaevanmax,'Reltol',1E-6,'AbsTol',1E-10);

qprop_p(a)=(Theta(w(a), T1,0)-Theta(w(a), T2, V)).*1/pi^2.*integral(@(beta)(sprop_p(w(a),beta,d)),0,w(a)/c);

qprop_s(a)=(Theta(w(a), T1,0)-Theta(w(a), T2, V)).*1/pi^2.*integral(@(beta)(sprop_s(w(a),beta,d)),0,w(a)/c);

a/length(w)% progress indicator

end

qtot=qevan_p+qevan_s+qprop_p+qprop_s; %total intensity spectum

qtot=qtot*1.5193E15/10000; %in w/cm2/eV

qprop=(qprop_p+qprop_s)*1.5193E15/10000; %prop waves only, in w/cm2/eV

qevan=(qevan_p+qevan_s)*1.5193E15/10000; %evan waves only, in w/cm2/eV

bb=blackb(w,T1)*1.5193E15/10000; %in w/cm2/eV

%Spectral efficiency calculation

Q_total=integral(qtot(w(a)),0,w);

Answer 1

[Torsten]

The first argument to "integral" has to be a function or a function handle. Both does not seem to be the case in the call

Q_total=integral(qtot(w(a)),0,w);

If qtot is given as an array of values defined at the values of the vector w, maybe

Q_total = trapz(w,qtot)

is what you want.

[Ambali Odebowale]

This works!!! Thanks so much