C**** TTEST ***********
C PROG READS IN 4 ARRAYS- AVER, SD, AVER, SD
C AND DOES POINT BY POINT STUDENTS t TEST 
C
C
C   *******    OUTPUT IS t X 100 *********
C
C
C
C
C WRITTEN BY RAM 17 APR 86
C
C
C

	PARAMETER (MAP$ = 16384)
	DIMENSION AAV1(MAP$),SSD1(MAP$)
        DIMENSION AAV2(MAP$),SSD2(MAP$),TTEST(MAP$)
	INTEGER*4 NIN1,NIN2,NIN3,NIN4,NTST,NX,NY
        INTEGER*4 NZ,NXYZ(3),MXYZ(3),MODE
	CHARACTER IAV1*60,IAV2*60,ISD1*60,ISD2*60
        CHARACTER THEDATE*9,THETIME*9
	REAL*4 LABELOUT(20,10,2),LABELIN(20,10),TITLE(20)
	EQUIVALENCE (NX,NXYZ(1)), (NY,NXYZ(2)), (NZ,NXYZ(3))
C
C

        NIN1=1
        NIN2=2
        NIN3=3
        NIN4=4
        NTST=7
	CALL TIME(THETIME)				
	CALL DATE(THEDATE)
	WRITE(6,1000)					
	READ(5,1002) TITLE				
	READ(5,*) N1
	READ(5,1005,END=100) IAV1 		
	READ(5,1005,END=100) ISD1 		
        READ(5,*) N2
	READ(5,1005,END=100) IAV2 		
	READ(5,1005,END=100) ISD2 		
        WRITE(6,*) N1
       	WRITE(6,1001) IAV1				
	WRITE(6,1001) ISD1				
        WRITE(6,*) N2
	WRITE(6,1001) IAV2
	WRITE(6,1001) ISD2				
	CALL IMOPEN(NIN1,IAV1,'RO')			
	CALL IRDHDR(NIN1,NXYZ,MXYZ,MODE,DMIN,DMAX,DMEAN)
	CALL IMOPEN(NIN2,ISD1,'RO')			
	CALL IRDHDR(NIN2,NXYZ,MXYZ,MODE,DMIN,DMAX,DMEAN)
	CALL IMOPEN(NIN3,IAV2,'RO')			
	CALL IRDHDR(NIN3,NXYZ,MXYZ,MODE,DMIN,DMAX,DMEAN)
	CALL IMOPEN(NIN4,ISD2,'RO')			
	CALL IRDHDR(NIN4,NXYZ,MXYZ,MODE,DMIN,DMAX,DMEAN)
        CALL IMOPEN(NTST,'TSTAT','NEW')			
        CALL ITRHDR(NTST,NIN1)				
        NNXX = NX					
        NNYY = NY					
	NNZZ = NZ					
	NPTS = NX*NY
100	IY = 0						
	DMEAN = 0.0
	DMAX = -1E7
	DMIN =  1E7
        N1LS1 = N1-1
        N2LS1 = N2-1
        IDEGF = N1LS1 + N2LS1
        RECIP1 = 1/FLOAT(N1)
        RECIP2 = 1/FLOAT(N2)
        CIPSUM = RECIP1 + RECIP2
        BTBIT = SQRT(CIPSUM)
	DO NSEC = 1 , NNZZ				
          ISEC = NSEC -1				
	  CALL IMPOSN(NIN1,ISEC,IY)			
	  CALL IRDSEC(NIN1,AAV1,*99)			
	  CALL IMPOSN(NIN2,ISEC,IY)			
	  CALL IRDSEC(NIN2,SSD1,*99)			
	  CALL IMPOSN(NIN3,ISEC,IY)			
	  CALL IRDSEC(NIN3,AAV2,*99)			
	  CALL IMPOSN(NIN4,ISEC,IY)			
	  CALL IRDSEC(NIN4,SSD2,*99)			
	  DO J = 1 , NPTS				
            SD1SQ = SSD1(J) **2
            SD2SQ = SSD2(J) **2
            AMNDIF = AAV1(J) - AAV2(J)
            AMNDIF = ABS(AMNDIF)
            VAR1=(FLOAT(N1LS1)*SD1SQ)+(FLOAT(N2LS1)*SD2SQ)
            IF (VAR1.LE.0) THEN
             TTEST(J) = 0
             ELSE
             VAR = VAR1/FLOAT(IDEGF)
             SDPOP = SQRT(VAR)
             TTEST(J) = AMNDIF/(SDPOP*BTBIT)
             TTEST(J) = TTEST(J) * 100
              IF (TTEST(J).LT.DMIN) DMIN=TTEST(J)
              IF (TTEST(J).GT.DMAX) DMAX=TTEST(J)
             DMEAN = DMEAN + TTEST(J)			
C              IF (TTEST(J).LE.200) TTEST(J) = 0
            END IF
           END DO 
	  CALL IMPOSN(NTST,ISEC,IY)			
	  CALL IWRSEC(NTST,TTEST)			
	END DO
	DMEAN = DMEAN / NPTS / NNZZ			
        WRITE (6,1993) DMIN,DMAX,DMEAN
	CALL IWRHDR(NTST,TITLE,-1,DMIN,DMAX,DMEAN)	
	CALL IMCLOSE(NTST)				
	GO TO 200
99	WRITE(6,1006)
1000	FORMAT(/,' TTEST , Version 1.0:  Calculate TTEST  ',
     $' between two ')
1001	FORMAT(/,' ********** INPUT FILE:  ',A/)
1992    FORMAT(5X,'THIS AFTER IWRSEC CALL')
1993   FORMAT (5X,3F10.5)
1002	FORMAT(20A4)
1003	FORMAT(//,' Map dimensions too large for program, NX =',I5,
     A		', NY =',I5,', map limit =',I10)
1004	FORMAT(' !! Dimensions of input map do not match output map!!')
1005	FORMAT(A)
1006	FORMAT(/' END OF FILE ON MAP INPUT FILE !!!!')
1010	FORMAT('TTESTMAP, Version 1.0: Calculate TTEST  map',A,', ',A)
1011	FORMAT('TTESTMAP, Version 1.0: Calculate TTEST  map ',A,', ',A)
200	CALL EXIT
	END