SUBROUTINE LUDECP (A,UL,N,D1,D2,IER,m)
!C
real(8) a(m),ul(m)
! real(8) a(n*(n-1)/2),ul(n*(n-1)/2)
DOUBLE PRECISION D1,D2,ZERO,ONE,FOUR,SIXTN,SIXTH,X,RN
DATA ZERO,ONE,FOUR,SIXTN,SIXTH/0.0D0,1.D0,4.D0,16.D0,.0625D0/
!C FIRST EXECUTABLE STATEMENT
D1=ONE
D2=ZERO
RN = ONE/(N*SIXTN)
IP = 1
IER=0
DO 45 I = 1,N
IQ = IP
IR = 1
DO 40 J = 1,I
X = A(IP)
IF (J .EQ. 1) GO TO 10
DO 5 K=IQ,IP1
X = X - UL(K) * UL(IR)
IR = IR+1
5 CONTINUE
10 IF (I.NE.J) GO TO 30
D1 = D1*X
IF (A(IP) + X*RN .LE. A(IP)) GO TO 50
15 IF (DABS(D1).LE.ONE) GO TO 20
D1 = D1 * SIXTH
D2 = D2 + FOUR
GO TO 15
20 IF (DABS(D1) .GE. SIXTH) GO TO 25
D1 = D1 * SIXTN
D2 = D2 - FOUR
GO TO 20
25 UL(IP) = ONE/DSQRT(X)
GO TO 35
30 UL(IP) = X * UL(IR)
35 IP1 = IP
IP = IP+1
IR = IR+1
40 CONTINUE
45 CONTINUE
GO TO 9005
50 IER = 129
9000 CONTINUE
write(*,*)'error in ludecp'
9005 RETURN
END