Question

How to calculate the determinant of a 3X3 matrix in Swift

Answer 1

import Foundation

func CalculateTheDeterminantOf3X3Matrix() {
    let arr: [[Float]] = [[6, 1, 1], [4, -2, 5], [2, 8, 7]]
        
    let determinant = arr[0][0] * (arr[1][1] * arr[2][2] - arr[1][2] * arr[2][1]) -
                      arr[0][1] * (arr[1][0] * arr[2][2] - arr[1][2] * arr[2][0]) +
                      arr[0][2] * (arr[1][0] * arr[2][1] - arr[1][1] * arr[2][0])
        
    print(determinant)
}

CalculateTheDeterminantOf3X3Matrix()


/* 
       a b c
 arr = d e f
       g h i
    
 determinant = a*(e*i - f*h) - b*(d*i-f*g) + c*(d*h - e*g)
     
*/ 

 
/*
run:
 
-306.0
 
*/

 

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