Visual C++ :: Pointer To Function Type - Calculating New Variable?

I'm fairly new to C++ and have begun working with pointers. I wish to create am array called sigmaf_point that reads data from a text file. I have managed to get that working, but when it comes to using this pointer I come across some problems. The array is created as such:

Code:
double sigma [5];
double *sigmaf_point = sigma;
void read(double *&sigmaf_point)
string s;
ifstream Dfile;
std::stringstream out;

[Code] .....

I then create a coordinate system inside the main file, as the program I am writing is about modelling the movement of atoms, which requires you to know the coordinates:

Code:
int main();
double **coords_fluid = new double*[5000];
for (int i = 0; i < n_atoms_methane; i++) {
coords_fluid[i] = new double[4];
}

Now, the problem arises when I want to calculate a new variable as so:

Code:
for (int i = 0; i <= n_atoms-1; i++) {
sf1=sigmaf_point(coords_fluid[i][3]);
}

I get the error C2064: term does not evaluate to a function taking 1 arguments, and a red line under sigmaf_point that says it must be pointer to function type. I am a bit confused about this.