void matrix_setup(complex_array& A)
{ int n = 4;
A.get(0,0) = 3.0;
A.get(0,1) =1.0;
A.get(0,2) =-4.0;
A.get(0,3) =2.0;
A.get(1,0) =3.0;
A.get(1,1) =1.0;
A.get(1,2) =0.0;
A.get(1,3) =2.0;
A.get(2,0) =2.0;
A.get(2,1) =13.0;
A.get(2,2) =-1.0;
A.get(2,3) =0.0;
A.get(3,0) =-2.0;
A.get(3,1) =3.0;
A.get(3,2) =-1.0;
A.get(3,3) =4.0;
for (int i = 1; i < n; i++ )
{
for (int j = 0; j < i; j++ )
std::swap(A.get(i,j),A.get(j,i));
}
}
void lu_decompose_burke(int n, complex_array& a, int_array& ip, int ndim)
{
/*C
C Un-transpose the matrix for Gauss elimination
C
DO 12 I=2,N
DO 11 J=1,I-1
ARJ=A(I,J)
A(I,J)=A(J,I)
A(J,I)=ARJ
11 CONTINUE
12 CONTINUE
*/
// for (int i = 1; i < n; i++ )
// {
// for (int j = 0; j < i; j++ )
// std::swap(a.get(i,j),a.get(j,i));
// }
/*
IFLG=0
DO 9 R=1,N
*/
complex_array d(n);
for (int r = 0; r < n; r++ )
{
bool iflg=false;
/*C
C STEP 1
C
DO 1 K=1,N
D(K)=A(K,R)
1 CONTINUE*/
for (int k = 0; k < n; k++ )
d[k]= a.get(k,r);
/*
C
C STEPS 2 AND 3
C
RM1=R-1
IF (RM1.LT.1) GO TO 4
DO 3 J=1,RM1
PJ=IP(J)
ARJ=D(PJ)
A(J,R)=ARJ
D(PJ)=D(J)
JP1=J+1
DO 2 I=JP1,N
D(I)=D(I)-A(I,J)*ARJ
2 CONTINUE
3 CONTINUE
4 CONTINUE
*/
int rm1 = r - 1;
if (rm1 >= 0)
{
for (int j=0; j < r; j++)
{
int pj = ip[j];
nec_complex arj = d[pj];
a.set(j,r,arj);
d[pj] = d[j];
int jp1 = j + 1;
for (int i=jp1;i<n;i++)
d[i] -= a.get(i,j)*arj;
}
}
/*
C
C STEP 4
C
DMAX=REAL(D(R)*CONJG(D(R)))
IP(R)=R
RP1=R+1
IF (RP1.GT.N) GO TO 6
DO 5 I=RP1,N
ELMAG=REAL(D(I)*CONJG(D(I)))
IF (ELMAG.LT.DMAX) GO TO 5
DMAX=ELMAG
IP(R)=I
5 CONTINUE
6 CONTINUE
IF (DMAX.LT.1.E-10) IFLG=1
PR=IP(R)
A(R,R)=D(PR)
D(PR)=D(R)
*/
nec_float dmax = norm(d[r]);;
ip[r] = r;
int rp1 = r + 1;
if (rp1 < n)
{
for (int i=rp1; i<n; i++)
{
nec_float elmag = norm(d[i]);
if (elmag >= dmax)
{
dmax = elmag;
ip[r] = i;
}
}
}
if (dmax < 1e-10)
iflg = true;
int pr = ip[r];
a.set(r,r,d[pr]);
d[pr] = d[r];
/*
C
C STEP 5
C
IF (RP1.GT.N) GO TO 8
ARJ=1./A(R,R)
DO 7 I=RP1,N
A(I,R)=D(I)*ARJ
7 CONTINUE
8 CONTINUE
*/
if (rp1 < n)
{
nec_complex arj = cplx_10() / a.get(r,r);
for (int i=rp1; i<n; i++)
{
a.set(i,r,d[i] * arj);
}
}
/*
IF (IFLG.EQ.0) GO TO 9
WRITE(3,10) R,DMAX
IFLG=0
*/
if (iflg == true)
{
cout << "FACTR: PIVOT(" << r << ")=" << dmax;
iflg = false;
}
}
// increment ip array
for (int i=0;i<n;i++)
ip[i] += 1;
/*
cout << "solved = ";
to_octave(a,n,ndim);
cout << "ip = ";
to_octave(ip,n);
*/
}
