I am trying to make a 2×2 matrix from two 2D arrays that contain values in C.The Matrix to be produced, named overlap and is a 2×2 matrix, has elements that are functions of each D and A Arrays.
I have written the following code and its output shown below.
I don’t know what I am doing wrong and was wondering if whoever reads this can help a misguided new C learner.
P.S. I know I can write each element explicitly then put them into a matrix without using an array; however, I plan to use this skeleton as a foundation for an automation caculcation code for bigger input.
Thank you all for your time and effort,
Moe

    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    #define BASISFUN 2
    #define PI 3.14159265358979323846
    void overlaps(double overlap[][2], double d[][2], double a[][2]){
    printf("nThe Overlap Matrix isn");
    for (int i = 0; i < BASISFUN; i++) {  
    for (int j = 0; j < BASISFUN; j++) {
    overlap[i][j] = 0.0;
    if (i == j && i == 0){
    overlap[0][0] = pow(d[0][0], 2.0) * pow((PI/(a[0][0] + a[0][0])), 1.5);
    } else if (i == j && i == 1){
    overlap[1][1] = pow(d[1][1], 2.0) * pow((PI/(a[1][1] + a[1][1])), 1.5);
    } else if (i != j && i == 1){
    overlap[1][0] = pow(d[1][0], 2.0) * pow((PI/(a[1][0] + a[1][0])), 1.5);
    } else {
    overlap[0][1] = pow(d[0][1], 2.0) * pow((PI/(a[0][1] + a[0][1])), 1.5);
    }
    printf("%.4ft", overlap[i][j]);
    }
    printf("n");
    }
    }
    int main(){
    double A1 = 0.532149;
    double A2 = 4.097728; 
    double D1 = 0.82559;
    double D2 = 0.28317;
    double a[1][2] = {A1, A2};
    double d[1][2] = {D1, D2};
    double overlap[2][2];
    overlaps(overlap, d, a);
    return 0;
    }

OUTPUT:
The Orbital Coefficient Matrix is
3.4567  0.0190  
3.6998  44.0676 

However, the product is supposed to be as follows when using Matlab, which is 100% correct:
    3.4567    0.1307
    0.1307    0.0190