C  SYNFITP3
C
C       VX1.1   RH      24.2.95 converted to unix
C       VX1.2   RH      5.11.98 add PARAMETER increase dimensions
C
C  VAX VERSION  JULY 84
C  VERSION FOR P3; USES GUIDE POINTS FROM PREVIOUS CURVES
C  IF REQUIRED; THESE POINTS INCLUDED WITH DATA FOR LINE WITH
C  FILM NUMBER SET TO 0
C  FIT SYNC FUNCTIONS TO LATTICE LINES PRODUCED BY MERGHIGH
C  WITH OR WITHOUT PREPARATION OF INPUT DATA SET FOR PLOTTING
C  VERSION INCLUDES ESTIMATES OF ERRORS IN SYNC FUNCTION COEFFS
C  AND ERRORS IN FITTED CURVE.  ALSO CALCULATES MERGING R-FACTORS
C  UNIT 2 USED FOR FITTED CURVES
C  THIS VERSION DOES NOT ELIMINATE NEGATIVE SYNC FUNCTION COEFFS
C    MISSING REGIONS OF THE LATTICE LINE ARE FILLED IN AS INTERNAL
C    GUIDE POINTS
C
C     THERE WILL BE AN OPTION WHICH WILL ALLOW PRINT OUT OF A COMPLETE
C     SET OF RECIPROCAL LATTICE AMPLITUDES IN A 500 ANGSTROM UNIT CELL FOR
C     SUBSEQUENT USE IN COMPUTING THE THREE-DIMENSIONAL STRUCTURE.
C
C    DATA SETS USED ARE:-
C     (1)  LATTICE LINE DATA POINTS FOR CURVE FITTING
C         FORMAT OF DATASET:- TITLE RECORD,I10,10A4;
C                        H,K,ZSTAR,AMP,DIFF,IFILM (2I3,F7.4,2F8.1,I6)
C                        TERMINATED 100,100 ETC
C     (2)  DATASET FOR NEW FITTED CURVES
C         H K 'L' INT SIG 
C         FORMAT (2I4,3(2X,F8.1)); TERMINATED 100,100
C     (3)  OUTPUT FORMATTED LIST OF SYNC FUNCTION COEFFICIENTS
C         H K; 'L' COEFF
C         FORMAT F8.1, F12.3
C     (10) PLOT DATA SET READY FOR PROGRAM PLOTCRVS
C          BINARY DATA SET- SEE SUBROUTINE POINTS FOR CONTENT OF THIS
C
C    DATA CARDS ARE
C    (1) IPLOT     (*)
C    IF IPLOT=0, FITS SYNC FUNCTIONS AND COMPUTES R-FACTORS ONLY;
C    IF IPLOT=1, FITS SYNC FUNCTIONS, COMPUTES R-FACTORS, AND
C                PLOTS DATA POINTS AND FITTED CURVES
C    (2) ACELL,BCELL,GAMMA       (*)
C        2D UNIT CELL DIMENSIONS
C    (3) CCELL   C-axis cell dimension for syn-function fit.
C    (4) RESMAX,BSINC,SIGMIN,SIGMAX,SIGUID     (*)
C        RESMAX; DATA DISCARDED IF (1/D**2) > RESMAX (IN ANGS**-2)
C        BSINC;  APPLIES TEMP FACTOR EQUIVALENT TO 2*BSINC TO
C                SINCS IN CURVE FITTING
C        SIGMIN; MINIMUM SIGMA FOR CURVE FITTING
C        SIGMAX; MAXIMUM SIGMA FOR CURVE FITTING
C        SIGUID; SIGMA FOR INTERNAL GUIDE POINTS IS SIGUID*(AVERAGE 
C                SIGMA OF NEAREST DATA POINTS). SIGMA IS DOUBLED 
C                AS GUIDE POINTS GET FURTHER FROM DATA POINTS.
C     (5) SSQFIX,SSQDAT      (*)
C         IF SSQFIX=0.0, CALCULATE REQUIRED ERRORS SCALE FACTOR
C         FOR EACH LINE AND COMPUTE OVERALL SCALE FACTOR THAT
C         WILL BE NEEDED EVENTUALLY
C         IF SSQFIX=1.0, USE PREVIOUSLY CALCULATED SCALE FACTOR
C         FOR ALL LINES, SET BY SSQDAT
C       ALL THESE HAVE DEFAULT VALUES IF SET AS 0.
C
C
C
C     DATA SET IN PROGRAM BASED ON VALUE OF C THAT IS INPUT AS DATA:-
C          WSTAR
C          DZ
C          WLHALF
C          XMARGN
C          SNCSTP
C     IRFLMN;  MINIMUM NUMBER OF POINTS IN LATTICE LINE TO CURVE FIT
C
C       NMAX IS MAXIMUM NUMBER OF POINTS ON EACH LATTICE LINE
C       NCMX IS MAXIMUM NUMBER OF POINTS ON EACH FITTED CURVE
C