FUNCTION DDETRM(ARRAY,NORDER)
C
C	FUNCTION TO FIND DETERMINANT OF DOUBLE PRECISION ARRAY(NORDER,NORDER)
C
	REAL*8 ARRAY(NORDER,NORDER),SAVE,DETSAV
	DETSAV	= 1.			!INITIAL VALUE
	DO 50 K	= 1,NORDER		!DO ALL ROWS
	SAVE	= 1.E-30
	ISAVE	= 0
	DO 23 J	= K,NORDER		!FIND BIGGEST ELEMENT IN ROW
	IF(ABS(ARRAY(K,J)) .LT. SAVE)GO TO 23
	SAVE	= ABS(ARRAY(K,J))
	ISAVE	= J			!COLUMN NUMBER OF BIGGEST
23	CONTINUE
	IF(ISAVE .GT. 0)GO TO 31	!AOK IF FOUND BIGGEST
	DDETRM	= 0.			!NO LARGE ELEMENT, DETERMINANT=0
	RETURN				!NULL DETERMINANT
31	IF(ISAVE .EQ. K)GO TO 41	!IF ROW# = COLUMN DO NOT SWAP
	CALL SWAP(ARRAY(1,ISAVE),ARRAY(1,K),NORDER*4)
	DETSAV	= - DETSAV
41	DETSAV	= DETSAV * ARRAY(K,K)
	IF(K .GE. NORDER) GO TO 50
	KI	= K 
	KI	= K + 1
	DO 46 I	= KI,NORDER		!DO ELEMENTARY ROW MANIPULATION
	DO 46 J	= KI,NORDER		!AND COLUMN MANIPULATION
C		PRODUCE ALL ZERO ELEMENTS IN ROW + COLUMN ON DIAGONAL
46	ARRAY(I,J)	= ARRAY(I,J) - ARRAY(I,K)*ARRAY(K,J)/ARRAY(K,K)
50	CONTINUE
	DDETRM	= DETSAV
	RETURN				!ANSWER IS NON ZERO
	END