I have written a tool that provides a (relatively) "high-level" access to GSL by using an input text file. You can see that same rewritten using my tool and reading the data from a textfile example here
https://www.seamplex.com/wasora/realbook/real-020-gsl.html#nlfit.was The tool, which is GPLv3+, can be obtained here https://www.seamplex.com/wasora If you still need to read the a two-columns text file into two C arrays, you should be searching on stackoverflow or so. Regards -- jeremy theler www.seamplex.com On Wed, 2019-04-17 at 07:46 +0000, Lawrence Habahbeh wrote: > Hi, > > In the online [Docs]( > https://www.gnu.org/software/gsl/doc/html/index.html > ) ยป 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, > > Sent with [ProtonMail]( > https://protonmail.com > ) Secure Email.