[Help-gsl] Nonlinear Least-Squares Fitting

[Lawrence Habahbeh]

Hi,

In the online [Docs](https://www.gnu.org/software/gsl/doc/html/index.html) » 
Nonlinear Least-Squares Fitting, there is an example of fitting an exponential 
function  to data. The data object is a structure with three arguments
struct data {
size_t n;
double *t;
double *y;
};

Can you please show me how to read the data from a text file and run the 
optimization as is. . The data is a column vector with daily observations and T 
= 120000 points .

Kind regards,

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