I have the error Attempted to access Irs(1.21516); index must be a positive integer or logical.

Question

shrik kader 2017-5-30

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回答： Steven Lord 2017-5-30

while the code is

 clc 
 close all 
 Gref = 1000; %reference irradiance
 Tcref=25+273; % reference temperature in Kelvin
 Tc=45+273; % opertion temperature in Kelvin 
 G=800; % operation irradiance
 Rs=0.39383;
 vocref=36.3;
 Eg=1.12; % band gap of material
 Iscref=7.84;
 A=0.98117; % ideality factor of diode
 q = 1.6e-19; 
 k = 1.38e-23;
 Ns=60;
 Ki=0.102;
 Ipv=(G/Gref)*(Iscref+Ki*(Tc-Tcref));
 vtn=(A*k*Tcref*Ns)/q;
 Irs= Iscref/(exp(vocref/(A*vtn))-1);
 Io= Irs((Tc/Tcref)^3)*exp(((Eg*q)/(A*K))*((1/Tcref)-(1/Tc)));
 Id=Io(exp((q*(v+I*Rs)/(A*K*Tc*Ns))-1));
 i = 0;   % Set initial current
 x=1;
 I = zeros(1,30);
 for v=0:0.005:36.3
 I(x)= Ipv - Io*(exp((q*(v+i*Rs)/(A*K*Tc*Ns))-1)) - ((v+Rs)/Rsh);
 i = I(x) %Update Current
 x=x+1;
 end
 v=0:0.005:36.3;
 P = I.*v; 
 plot(v,P)
 grid on

what should I do ?. P.S: I am still beginner.

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shrik kader 2017-5-30

Stephen Cobeldick, As I said I am beginner, what do you suggest to do ?

Stephen23 2017-5-30

编辑：Stephen23 2017-5-30

@shrik kader: I don't know what your algorithm is, so unless you describe exactly what you are trying to achieve, I can only guess. My guess is that you might need interpolation of your data:

https://www.mathworks.com/help/matlab/interpolation.html

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Answer 1

Steven Lord 2017-5-30

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/342554-i-have-the-error-attempted-to-access-irs-1-21516-index-must-be-a-positive-integer-or-logical#answer_268963

在 MATLAB Online 中打开

If on this line of code:

Io= Irs((Tc/Tcref)^3)*exp(((Eg*q)/(A*K))*((1/Tcref)-(1/Tc)));

you're attempting to multiply Irs by ((Tc/Tcref)^3) and multiply the result by the exponential of another quantity, you're missing the first multiplication.

Io= Irs*((Tc/Tcref)^3)*exp(((Eg*q)/(A*K))*((1/Tcref)-(1/Tc)));

If instead you have a vector Irs containing data and an associated "index" vector and want to interpolate the Irs vector to obtain data at some point that is not present in the "index" vector, as Stephen said you will need to interpolate.