C		Iwannou Spyros,Kontopodhs Dhmhtrhs

		PROGRAM EROTISI 1
		REAL M1,A(3,3),D(4,4),B(3),WORK(3),WORK1(4),COND,TEST,RNORM,ANORM
		REAL A1(3,3),R(3,3)
		INTEGER IPVT(3),IPVT1(4),N, NDIM, I, J
		NDIM=3
		N=3
		DATA ((A(I,J),I=1,3),J=1,3)/5.,-1.5,2.5,-3.5,1.,-0.5,0.,3.,2.5/
		DATA ((A1(I,J),I=1,3),J=1,3)/5.,-1.5,2.5,-3.5,1.,-0.5,0.,3.,2.5/
		DATA (B(I),I=1,3)/3.5,2.,3./
		DATA ((D(I,J),I=1,4),J=1,4)/-1.,0.,4.,7.,2.,0.,-3.,1.,-12.,
     a  -11.,-9.,6.,15.,11.,7.,3./

		CALL DECOMP(NDIM,N,A,COND,IPVT,WORK)

		TEST=COND+1
		IF (COND.EQ.TEST) THEN
		PAUSE 'PINAKAS MH ANTISTREPSIMOS'
		STOP
		ENDIF

		CALL SOLVE(NDIM,N,A,B,IPVT)

2   	FORMAT('X',I1,'=',F8.3)
		DO 5 I=1,N
		WRITE(6,2) I, B(I)
5   	CONTINUE
		PAUSE 'PATHSTE RETURN GIA UPOLOGISMO M1'

		CALL INVERT(A1,R,N,NDIM)
		CALL NORM(A1,ANORM)
		CALL NORM(R,RNORM)
		M1=RNORM*ANORM
30  	FORMAT('TO M1 EINAI:M1=',F10.5)
		WRITE(6,30) M1
		S=((M1-COND)/M1)*100
32 		 FORMAT('COND=',F18.5)
33  	FORMAT('TO Sxetiko Sfalma S=',F9.3,'%')
		WRITE(6,32) COND
		WRITE(6,33) S

		PAUSE 'PATHSTE RETURN GIA TON UPOLOGISMO TOU D'

		NDIM=4
		N=4

		CALL DECOMP(NDIM,N,D,COND,IPVT1,WORK1)

		WRITE(6,32) COND
		STOP
		END

		SUBROUTINE NORM(A,ANORM)
		REAL A(3,3), ANORM,T

		ANORM=0.0
		DO 45 J=1,3
 		 T=0.0
		DO 40 I=1,3
		 T=T+ABS(A(I,J))
40		CONTINUE
		IF (T.GT.ANORM) ANORM=T
45		CONTINUE
		RETURN
		END


		SUBROUTINE INVERT(A,R,N,NDIM)
		INTEGER N,IPVT(N),I,J,NDIM
		REAL R(NDIM,N),A(NDIM,N),WORK(N),COND,T(N,N),M(N)
		DO 48 J=1,N
		DO 48 I=1,N
		T(I,J)=A(I,J)
48		CONTINUE
		CALL DECOMP(NDIM,N,A,COND,IPVT,WORK)
		IF ((COND+1).EQ.COND) THEN
		WRITE(6,*) 'PINAKAS MH ANTISTREPSIMOS,PROBLHMA STHN KLHSH INVERT'
		RETURN
		ENDIF

		DO 60 J=1,N
		DO 50 I=1,N
		IF (I .EQ. J)	THEN
			M(I)=1
		ELSE 
			M(I)=0
		ENDIF
50		CONTINUE
		CALL SOLVE(NDIM,N,A,M,IPVT)
		DO 55 I=1,N
		R(I,J)=M(I)
55		CONTINUE
60		CONTINUE
		DO 70 J=1,N
		DO 70 I=1,N

C		Epanaferei ton A pou prohgoumenws eixe krathsei ston pinaka T

		A(I,J)=T(I,J)
70		CONTINUE
		RETURN
		END