Matrix basic operations (plus and minus multiplication, inversion, transpose)

Look at the template, find the best understanding, best use the matrix basic operation template

#define MAXN 100
#define ZERO (x) (Fabs (x) <1e-10)
struct MAT
{
int n,m;
Double DATA[MAXN][MAXN];
};
Matrix Plus and minus multiplication
int Add (mat& c,const mat& a,const mat& b)
{
int i,j,k;
if (a.m!=b.m| | A.N!=B.N)
return 0;
C.N=A.N;
C.M=A.M;
for (i=0; i<c.n; i++)
for (j=0; j<c.m; j + +)
C.DATA[I][J]=A.DATA[I][J]+B.DATA[I][J];
return 1;
}
int Jian (mat& c,const mat& a,const mat& b)
{
int i,j,k;
if (a.m!=b.m| | A.N!=B.N)
return 0;
C.N=A.N,C.M=A.M;
memset (c.data,0,sizeof (c.data));
for (i=0; i<c.n; i++)
for (j=0; j<c.m; j + +)
C.DATA[I][J]=A.DATA[I][J]-B.DATA[I][J];
return 1;
}
int Mul (mat& c,const mat& a,const mat& b)
{
int i,j,k;
if (A.M!=B.N)
return 0;
C.N=A.N,C.M=B.M;
for (i=0; i<c.n; i++)
for (j=0; j<c.m; j + +)
for (c.data[i][j]=k=0; k<a.m; k++)
C.DATA[I][J]+=A.DATA[I][K]*B.DATA[K][J];
return 1;
}
Inverse of matrix
int INV (mat& a)
{
int I,J,K,IS[MAXN],JS[MAXN];
Double T;
if (A.N!=A.M)
return 0;
for (k=0; k<a.n; k++)
{
for (t=0,i=k; i<a.n; i++)
for (j=k; j<a.n; j + +)
if (Fabs (A.data[i][j]) >t)
T=fabs (A.data[is[k]=i][js[k]=j]);
if (zero (t))
return 0;
if (is[k]!=k)
for (j=0; j<a.n; j + +)
Swap (a.data[k][j],a.data[is[k]][j]);
if (js[k]!=k)
for (i=0; i<a.n; i++)
Swap (A.data[i][k],a.data[i][js[k]]);
A.DATA[K][K]=1/A.DATA[K][K];
for (j=0; j<a.n; j + +)
if (j!=k)
A.DATA[K][J]*=A.DATA[K][K];
for (i=0; i<a.n; i++)
if (i!=k)
for (j=0; j<a.n; j + +)
if (j!=k)
A.DATA[I][J]-=A.DATA[I][K]*A.DATA[K][J];
for (i=0; i<a.n; i++)
if (i!=k)
A.DATA[I][K]*=-A.DATA[K][K];
}
for (k=a.n-1; k>=0; k--)
{
for (j=0; j<a.n; j + +)
if (js[k]!=k)
Swap (a.data[k][j],a.data[js[k]][j]);
for (i=0; i<a.n; i++)
if (is[k]!=k)
Swap (A.data[i][k],a.data[i][is[k]]);
}
return 1;
}
Transpose matrix, eg2*2 matrix: [1 2 3 4]->[-2,1,1.5,-0.5]
Double det (const mat& a)
{
int i,j,k,sign=0;
Double b[maxn][maxn],ret=1,t;
if (A.N!=A.M)
return 0;
for (i=0; i<a.n; i++)
for (j=0; j<a.m; j + +)
B[I][J]=A.DATA[I][J];
for (i=0; i<a.n; i++)
{
if (zero (b[i][i)))
{
for (j=i+1; j<a.n; j + +)
if (!zero (B[j][i]))
Break
if (J==A.N)
return 0;
for (k=i; k<a.n; k++)
Swap (b[i][k],b[j][k]);
sign++;
}
Ret*=b[i][i];
for (k=i+1; k<a.n; k++)
B[i][k]/=b[i][i];
for (j=i+1; j<a.n; j + +)
for (k=i+1; k<a.n; k++)
B[J][K]-=B[J][I]*B[I][K];
}
if (sign&1)
Ret=-ret;
return ret;
}
int main ()
{
Mat A,b,c;
while (scanf ("%d%d", &AMP;A.N,&AMP;A.M)!=eof)
{
for (int i=0; i<a.n; i++)
for (int j=0; j<a.m; j + +)
scanf ("%lf", &a.data[i][j]);
X=INV (a);
B.n=2,b.m=1;
b.data[0][0]=2;
b.data[1][0]=3;
Y=mul (C,A,B);
for (int i=0; i<c.n; i++)
{
for (int j=0; j<c.m; j + +)
printf ("%lf", C.data[i][j]);
printf ("\ n");
}
Double M=det (a);
cout<<m<<endl;
for (int i=0; i<a.n; i++)
{
for (int j=0; j<a.m; j + +)
printf ("%lf", A.data[i][j]);
printf ("\ n");
}
}
return 0;
}

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Matrix basic operations (plus and minus multiplication, inversion, transpose)