This example solves a complex symmetric system of equations where the number of equations and right-hand side vectors are input. Subroutines CSUBLK is used to define matrix coefficients in the lower triangle and diagonal. The matrix size is only limited by the available disk space. 
C       E X A M P L E   10
C
C	Program name:
	CHARACTER*10 MYNAME
	PARAMETER (MYNAME='EXAMPLE_10')
C
C	Input data functions:
	INTEGER ASK_I
C
C	Data type = complex:
	PARAMETER (IDTYPE = 2)
C
C	Number of vectors to reduce during factoring:
	PARAMETER (NUMRED = 0)
C
C	Skip operations during solving (no):
	PARAMETER (ISKIP  = 0)
C
C	FMS matrix and vector file attributes:
	INTEGER     LUF(25)
	INTEGER     LUX(25)
C
C	FMS memory management requires the following arrays:
	POINTER (CMD_PTR, CMD)
	POINTER (RMD_PTR, RMD)
	POINTER (IMD_PTR, IMD)
	COMPLEX*16 CMD(0:1)
	REAL*8     RMD(0:1)
	INTEGER    IMD(0:1)
C
C	Profile vector for a full matrix:
	INTEGER LOWEQ(1)
C
C	Local variables:
	INTEGER     N, NRHS, I, LX, LENX, LDISK, NV
	REAL*8      EI, ERROR
C
C	Common block to communicate with CSUBLK:
	COMMON /MYDATA/NUMEQ
	DATA        LOWEQ/-1/
C
C (1)   Initialize FMS:
	CALL FMSINI
	CALL FMSPSH(MYNAME)
	CALL FMSIST ('MDATAU', 2)
	CALL FMSIGT ('MEMPTR', IMD_PTR)
	CALL FMSIGT ('MEMPTR', RMD_PTR)
	CALL FMSIGT ('MEMPTR', CMD_PTR)
	N    = ASK_I ('Enter the number of equations')
	NRHS = ASK_I ('Enter the number of solution vectors')
C
C (2)   Open FMS files:
	CALL CSDI (LOWEQ, N, 'LUF', LUF)
	CALL FMSOV (N, IDTYPE, NRHS, 'LUX', LUX)
C
C       Populate test vector:
C	Allocate enough space to hold a vector image on disk:
	LENX = LUX(4)/2
	CALL FMSCMG (CMD, LX, LENX)
	NUMEQ  = N
	DO 10 I = 1,LENX
	   CMD(LX-1+I) = (0.0D0,0.0D0)
   10   CONTINUE
	CMD(LX) = (1.0D0,1.0D0)
C
C (3)   Write data to FMS files:
	LDISK  = 1
	DO 30 NV = 1,NRHS
	   CALL FMSWRT (LUX(1), LDISK, CMD(LX), LUX(4))
	   LDISK = LDISK + LUX(4)
   30   CONTINUE
C
C (4)   Perform matrix algebra:
	CALL CSDF (LUF, LUF, LUX, LUX,  NUMRED)
	CALL CSDS (LUF, LUX, LUX, NRHS, ISKIP)
C
C (5)   Read data from FMS files:
C       Check the answer:
	ERROR = 0.0D0
	LDISK  = 1
	DO 60 NV = 1,NRHS
	   CALL FMSRED (LUX(1), LDISK, CMD(LX), IDTYPE*N)
	   LDISK  = LDISK  + LUX(4)
	   DO 50 I = 1,N
	      EI = ABS(CMD(LX-1+I) - 1.0D0)
	      IF(EI .GT. ERROR) ERROR = EI
   50      CONTINUE
   60   CONTINUE
	WRITE(6,*) 'MAXIMUM ERROR =', ERROR
C
C (6)   Close FMS files:
	CALL FMSCM (LUF)
	CALL FMSCV (LUX)
	CALL FMSCMR (CMD, LX, LENX)
	CALL FMSPOP(MYNAME)
	CALL FMSEND
	END
C=======================================================================
	SUBROUTINE CSUBLK (A, D, LOWEQ, LOCEQ, IROW1, IROW2,
     1                     JCOL1, JCOL2, IJSTEP)
C=======================================================================
	INTEGER    IROW1, IROW2, JCOL1, JCOL2, IJSTEP
	INTEGER    LOWEQ(*), LOCEQ(*)
	COMPLEX*16 A(0:*), D(*), ONE
	PARAMETER  (ONE=(1.0D0,1.0D0))
	COMMON /MYDATA/NUMEQ
C
C       Populate the diagonal with test data:
	IF(IROW2 .EQ. JCOL2) THEN
C	   This is a diagonal block:
	   DO 10 I = IROW1,IROW2
	      D(I) = ONE
   10	   CONTINUE
	   IF(IROW1 .EQ. 1) D(1) = DCMPLX(NUMEQ,NUMEQ)
	END IF
C
C	Populate profile of [AL] with test data:
C	The term A(I,J) is addressed as A(LOCEQ(I)+IJSTEP*J)
	DO 20 I = IROW1,IROW2
	   J = LOWEQ(I)
	   IF( (J .GE. JCOL1) .AND.
     1	       (J .LE. JCOL2) .AND.
     2	       (J .LT.     I) ) A(LOCEQ(I) + IJSTEP*J) = -ONE
   20	CONTINUE
	RETURN
	END
C=======================================================================
	INTEGER FUNCTION ASK_I(STRING)
C=======================================================================
	CHARACTER* (*) STRING
	WRITE(6,2000) STRING
	READ (5,*) ASK_I
	RETURN
 2000	FORMAT (1X,A,'>')
	END