sum of series of following equation

lamda=0.3:0.01:1.4; % unit micro-meter

Ec2=(1.24./lamda);

alpho=2e4;

alpha= real(alpho.*(sqrt(Ec2-1.51)));

d=1e-4;

JPh2=exp(-1.*alpha.*d); % equation 1

lamda1=0.82;

% now the summation of eqaution 1 goes from 0 to lamda1,

so how to calculate this sum of series

Answer 1

[Ameer Hamza]

You can use logical indexing to isolate the required values and then use sum()

lamda=0.3:0.01:1.4;  % unit micro-meter
Ec2=(1.24./lamda);
alpho=2e4; 
alpha= real(alpho.*(sqrt(Ec2-1.51)));
d=1e-4;
JPh2=exp(-1.*alpha.*d);   %   equation 1
lamda1=0.82;

idx = lamda < lamda1;
out_value = sum(JPh2(idx));

[Arvind Sharma]

any other way to calculate

[Ameer Hamza]

What is wrong with this method?