Question

Reposting since I got no answer last time.

I need help with this gauss elimination program

Hi, I need help with this program, it's an algorythm in R. I need it to be done in c. #suppose ak! -0 k in step k ## Input data a- matrix (c (2.3, 1.4.4, -3.2,3.1, ncol-3, byrowT) b= c (5.3, -1) ## Triangularize for (k in 1: (n-1) for (i in (k + 1): n) I b li, Ji, m -a [i, k] / a [k, k] a [i, k] = 0 b [i b [i] -m b [k) for (j in (k 1): n) a [i, j] a [i, j] -ma [k, j] #Equivalent System Resolution x=0 x[n]=b[n]/a[n,n] for (k in (n-1)1) s-0 for (j in (k+1) :n)f s-sta[k, j]*x[j] x[k] (b[k]-s)/a[k,k]

Answer 1

Hi there,

please find the solution.

----------------------------------------------

#include<stdio.h>
int main()
{
int a,b,c,n;
float A[20][20],d,x[10],sum=0.0;
printf("\nOrder of matrix: ");
scanf("%d",&n);
printf("\nEnter the elements of augmented matrix row-wise:\n\n");
for(a=1; a<=n; a++)
{
for(b=1; b<=(n+1); b++)
{
printf("A[%d][%d] : ", a,b);
scanf("%f",&A[a][b]);
}
}
for(b=1; b<=n; b++) /*upper triangular matrix*/
{
for(a=1; a<=n; a++)
{
if(a>b)
{
d=A[a][b]/A[b][b];
for(c=1; c<=n+1; c++)
{
A[a][c]=A[a][c]-d*A[b][c];
}
}
}
}
x[n]=A[n][n+1]/A[n][n];
/*backward substitution*/
for(a=n-1; a>=1; a--)
{
sum=0;
for(b=a+1; b<=n; b++)
{
sum=sum+A[a][b]*x[b];
}
x[a]=(A[a][n+1]-sum)/A[a][a];
}
printf("\nThe solution is: \n");
for(a=1; a<=n; a++)
{
printf("\nx%d=%f\t",a,x[a]); /* x1, x2, x3 are the required solutions*/
}
return(0);
}

OUTPUT

Thanks

Feel free to write back.

Order of matrix:3 Enter the clements of augmonted matrix row-wise: 1 : 2.3 A[1] [2] : 一1.4 A1 3] : 4 AI21 :2 A121 [2]3 A[2] [4] : 5 A31 1 3 A3 2 1 A[31 3: 4 A31 4 5 The solution is: X1=9. 690.722 x2-3.041238 x3=-5.257 732