| [2403] | 1 | * | 
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|  | 2 | * $Id: mnhess.F,v 1.1.1.1 2003-06-11 14:18:28 cmv Exp $ | 
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|  | 3 | * | 
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|  | 4 | * $Log: not supported by cvs2svn $ | 
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|  | 5 | * Revision 1.1.1.1  1996/03/07 14:31:30  mclareni | 
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|  | 6 | * Minuit | 
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|  | 7 | * | 
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|  | 8 | * | 
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|  | 9 | #include "minuit/pilot.h" | 
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|  | 10 | SUBROUTINE MNHESS(FCN,FUTIL) | 
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|  | 11 | #include "minuit/d506dp.inc" | 
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|  | 12 | CC        Calculates the full second-derivative matrix of FCN | 
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|  | 13 | CC        by taking finite differences. When calculating diagonal | 
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|  | 14 | CC        elements, it may iterate so that step size is nearly that | 
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|  | 15 | CC        which gives function change= UP/10. The first derivatives | 
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|  | 16 | CC        of course come as a free side effect, but with a smaller | 
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|  | 17 | CC        step size in order to obtain a known accuracy. | 
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|  | 18 | CC | 
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|  | 19 | #include "minuit/d506cm.inc" | 
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|  | 20 | EXTERNAL FCN,FUTIL | 
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|  | 21 | DIMENSION YY(MNI) | 
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|  | 22 | LOGICAL LDEBUG | 
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|  | 23 | CHARACTER CBF1*22 | 
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|  | 24 | C | 
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|  | 25 | LDEBUG = (IDBG(3) .GE. 1) | 
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|  | 26 | IF (AMIN .EQ. UNDEFI)  CALL MNAMIN(FCN,FUTIL) | 
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|  | 27 | IF (ISTRAT .LE. 0) THEN | 
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|  | 28 | NCYC = 3 | 
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|  | 29 | TLRSTP = 0.5 | 
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|  | 30 | TLRG2  = 0.1 | 
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|  | 31 | ELSE IF (ISTRAT .EQ. 1) THEN | 
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|  | 32 | NCYC = 5 | 
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|  | 33 | TLRSTP = 0.3 | 
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|  | 34 | TLRG2  = 0.05 | 
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|  | 35 | ELSE | 
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|  | 36 | NCYC = 7 | 
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|  | 37 | TLRSTP = 0.1 | 
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|  | 38 | TLRG2  = 0.02 | 
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|  | 39 | ENDIF | 
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|  | 40 | IF (ISW(5).GE.2 .OR. LDEBUG)  WRITE (ISYSWR,'(A)') | 
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|  | 41 | +   '   START COVARIANCE MATRIX CALCULATION.' | 
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|  | 42 | CFROM = 'HESSE   ' | 
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|  | 43 | NFCNFR = NFCN | 
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|  | 44 | CSTATU= 'OK        ' | 
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|  | 45 | NPARD = NPAR | 
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|  | 46 | C                 make sure starting at the right place | 
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|  | 47 | CALL MNINEX(X) | 
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|  | 48 | NPARX = NPAR | 
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|  | 49 | CALL FCN(NPARX,GIN,FS1,U,4,FUTIL) | 
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|  | 50 | NFCN = NFCN + 1 | 
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|  | 51 | IF (FS1 .NE. AMIN) THEN | 
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|  | 52 | DF = AMIN - FS1 | 
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|  | 53 | WRITE (CBF1(1:12),'(G12.3)') DF | 
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|  | 54 | CALL MNWARN('D','MNHESS', | 
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|  | 55 | +       'function value differs from AMIN by '//CBF1(1:12) ) | 
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|  | 56 | ENDIF | 
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|  | 57 | AMIN = FS1 | 
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|  | 58 | IF (LDEBUG) WRITE (ISYSWR,'(A,A)') ' PAR D   GSTEP          ', | 
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|  | 59 | +' D          G2         GRD         SAG    ' | 
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|  | 60 | C                                        . . . . . . diagonal elements . | 
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|  | 61 | C         ISW(2) = 1 if approx, 2 if not posdef, 3 if ok | 
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|  | 62 | C         AIMSAG is the sagitta we are aiming for in second deriv calc. | 
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|  | 63 | AIMSAG = SQRT(EPSMA2)*(ABS(AMIN)+UP) | 
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|  | 64 | C         Zero the second derivative matrix | 
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|  | 65 | NPAR2 = NPAR*(NPAR+1)/2 | 
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|  | 66 | DO 10 I= 1,NPAR2 | 
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|  | 67 | 10 VHMAT(I) = 0. | 
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|  | 68 | C | 
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|  | 69 | C         Loop over variable parameters for second derivatives | 
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|  | 70 | IDRV = 2 | 
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|  | 71 | DO 100 ID= 1, NPARD | 
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|  | 72 | I = ID + NPAR - NPARD | 
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|  | 73 | IEXT = NEXOFI(I) | 
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|  | 74 | IF (G2(I) .EQ. ZERO) THEN | 
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|  | 75 | WRITE (CBF1(1:4),'(I4)') IEXT | 
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|  | 76 | CALL MNWARN('W','HESSE', | 
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|  | 77 | +      'Second derivative enters zero, param '//CBF1(1:4) ) | 
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|  | 78 | WINT = WERR(I) | 
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|  | 79 | IF (NVARL(IEXT) .GT. 1) THEN | 
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|  | 80 | CALL MNDXDI(X(I),I,DXDI) | 
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|  | 81 | IF (ABS(DXDI) .LT. .001) THEN | 
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|  | 82 | WINT = .01 | 
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|  | 83 | ELSE | 
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|  | 84 | WINT = WINT/ABS(DXDI) | 
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|  | 85 | ENDIF | 
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|  | 86 | ENDIF | 
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|  | 87 | G2(I) = UP/WINT**2 | 
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|  | 88 | ENDIF | 
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|  | 89 | XTF = X(I) | 
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|  | 90 | DMIN = 8.*EPSMA2*ABS(XTF) | 
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|  | 91 | C | 
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|  | 92 | C                               find step which gives sagitta = AIMSAG | 
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|  | 93 | D = ABS(GSTEP(I)) | 
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|  | 94 | DO 40 ICYC= 1, NCYC | 
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|  | 95 | C                               loop here only if SAG=0. | 
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|  | 96 | DO 25 MULTPY= 1, 5 | 
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|  | 97 | C           take two steps | 
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|  | 98 | X(I) = XTF + D | 
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|  | 99 | CALL MNINEX(X) | 
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|  | 100 | NPARX = NPAR | 
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|  | 101 | CALL FCN(NPARX,GIN,FS1,U,4,FUTIL) | 
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|  | 102 | NFCN = NFCN + 1 | 
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|  | 103 | X(I) = XTF - D | 
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|  | 104 | CALL MNINEX(X) | 
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|  | 105 | CALL FCN(NPARX,GIN,FS2,U,4,FUTIL) | 
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|  | 106 | NFCN = NFCN + 1 | 
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|  | 107 | X(I) = XTF | 
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|  | 108 | SAG = 0.5*(FS1+FS2-2.0*AMIN) | 
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|  | 109 | IF (SAG .NE. ZERO) GO TO 30 | 
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|  | 110 | IF (GSTEP(I) .LT. ZERO) THEN | 
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|  | 111 | IF (D .GE. .5)  GO TO 26 | 
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|  | 112 | D = 10.*D | 
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|  | 113 | IF (D .GT. 0.5)  D = 0.51 | 
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|  | 114 | GO TO 25 | 
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|  | 115 | ENDIF | 
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|  | 116 | D = 10.*D | 
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|  | 117 | 25 CONTINUE | 
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|  | 118 | 26      WRITE (CBF1(1:4),'(I4)') IEXT | 
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|  | 119 | CALL MNWARN('W','HESSE', | 
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|  | 120 | +      'Second derivative zero for parameter'//CBF1(1:4) ) | 
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|  | 121 | GO TO 390 | 
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|  | 122 | C                             SAG is not zero | 
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|  | 123 | 30 G2BFOR = G2(I) | 
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|  | 124 | G2(I) = 2.*SAG/D**2 | 
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|  | 125 | GRD(I) = (FS1-FS2)/(2.*D) | 
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|  | 126 | IF (LDEBUG) WRITE (ISYSWR,31) I,IDRV,GSTEP(I),D,G2(I),GRD(I),SAG | 
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|  | 127 | 31 FORMAT (I4,I2,6G12.5) | 
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|  | 128 | GSTEP(I) = SIGN(D,GSTEP(I)) | 
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|  | 129 | DIRIN(I) = D | 
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|  | 130 | YY(I) = FS1 | 
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|  | 131 | DLAST = D | 
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|  | 132 | D = SQRT(2.0*AIMSAG/ABS(G2(I))) | 
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|  | 133 | C         if parameter has limits, max int step size = 0.5 | 
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|  | 134 | STPINM = 0.5 | 
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|  | 135 | IF (GSTEP(I) .LT. ZERO)  D = MIN(D,STPINM) | 
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|  | 136 | IF (D .LT. DMIN)  D = DMIN | 
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|  | 137 | C           see if converged | 
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|  | 138 | IF (ABS((D-DLAST)/D)          .LT. TLRSTP)  GO TO 50 | 
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|  | 139 | IF (ABS((G2(I)-G2BFOR)/G2(I)) .LT. TLRG2 )  GO TO 50 | 
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|  | 140 | D = MIN(D, 10.*DLAST) | 
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|  | 141 | D = MAX(D, 0.1*DLAST) | 
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|  | 142 | 40 CONTINUE | 
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|  | 143 | C                       end of step size loop | 
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|  | 144 | WRITE (CBF1,'(I2,2E10.2)') IEXT,SAG,AIMSAG | 
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|  | 145 | CALL MNWARN('D','MNHESS','Second Deriv. SAG,AIM= '//CBF1) | 
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|  | 146 | C | 
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|  | 147 | 50 CONTINUE | 
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|  | 148 | NDEX = I*(I+1)/2 | 
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|  | 149 | VHMAT(NDEX) = G2(I) | 
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|  | 150 | 100 CONTINUE | 
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|  | 151 | C                              end of diagonal second derivative loop | 
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|  | 152 | CALL MNINEX(X) | 
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|  | 153 | C                                     refine the first derivatives | 
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|  | 154 | IF (ISTRAT .GT. 0) CALL MNHES1(FCN,FUTIL) | 
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|  | 155 | ISW(2) = 3 | 
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|  | 156 | DCOVAR = 0. | 
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|  | 157 | C                                        . . . .  off-diagonal elements | 
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|  | 158 | IF (NPAR .EQ. 1)  GO TO 214 | 
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|  | 159 | DO 200 I= 1, NPAR | 
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|  | 160 | DO 180 J= 1, I-1 | 
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|  | 161 | XTI = X(I) | 
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|  | 162 | XTJ = X(J) | 
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|  | 163 | X(I) = XTI + DIRIN(I) | 
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|  | 164 | X(J) = XTJ + DIRIN(J) | 
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|  | 165 | CALL MNINEX(X) | 
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|  | 166 | CALL FCN(NPARX,GIN,FS1,U,4,FUTIL) | 
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|  | 167 | NFCN = NFCN + 1 | 
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|  | 168 | X(I) = XTI | 
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|  | 169 | X(J) = XTJ | 
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|  | 170 | ELEM = (FS1+AMIN-YY(I)-YY(J)) / (DIRIN(I)*DIRIN(J)) | 
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|  | 171 | NDEX = I*(I-1)/2 + J | 
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|  | 172 | VHMAT(NDEX) = ELEM | 
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|  | 173 | 180 CONTINUE | 
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|  | 174 | 200 CONTINUE | 
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|  | 175 | 214 CALL MNINEX(X) | 
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|  | 176 | C                  verify matrix positive-definite | 
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|  | 177 | CALL MNPSDF | 
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|  | 178 | DO 220 I= 1, NPAR | 
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|  | 179 | DO 219 J= 1, I | 
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|  | 180 | NDEX = I*(I-1)/2 + J | 
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|  | 181 | P(I,J) = VHMAT(NDEX) | 
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|  | 182 | 219 P(J,I) = P(I,J) | 
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|  | 183 | 220 CONTINUE | 
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|  | 184 | CALL MNVERT(P,MAXINT,MAXINT,NPAR,IFAIL) | 
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|  | 185 | IF (IFAIL .GT. 0)  THEN | 
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|  | 186 | CALL MNWARN('W','HESSE', 'Matrix inversion fails.') | 
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|  | 187 | GO TO 390 | 
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|  | 188 | ENDIF | 
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|  | 189 | C                                        . . . . . . .  calculate  e d m | 
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|  | 190 | EDM = 0. | 
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|  | 191 | DO 230 I= 1, NPAR | 
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|  | 192 | C                              off-diagonal elements | 
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|  | 193 | NDEX = I*(I-1)/2 | 
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|  | 194 | DO 225 J= 1, I-1 | 
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|  | 195 | NDEX = NDEX + 1 | 
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|  | 196 | ZTEMP = 2.0 * P(I,J) | 
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|  | 197 | EDM = EDM + GRD(I)*ZTEMP*GRD(J) | 
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|  | 198 | 225     VHMAT(NDEX) = ZTEMP | 
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|  | 199 | C                              diagonal elements | 
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|  | 200 | NDEX = NDEX + 1 | 
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|  | 201 | VHMAT(NDEX) = 2.0 * P(I,I) | 
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|  | 202 | EDM = EDM  + P(I,I) * GRD(I)**2 | 
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|  | 203 | 230   CONTINUE | 
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|  | 204 | IF (ISW(5).GE.1 .AND. ISW(2).EQ.3 .AND. ITAUR.EQ.0) | 
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|  | 205 | + WRITE(ISYSWR,'(A)')' COVARIANCE MATRIX CALCULATED SUCCESSFULLY' | 
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|  | 206 | GO TO 900 | 
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|  | 207 | C                              failure to invert 2nd deriv matrix | 
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|  | 208 | 390 ISW(2) = 1 | 
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|  | 209 | DCOVAR = 1. | 
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|  | 210 | CSTATU = 'FAILED    ' | 
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|  | 211 | IF (ISW(5) .GE. 0) WRITE (ISYSWR,'(A)') | 
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|  | 212 | +        '  MNHESS FAILS AND WILL RETURN DIAGONAL MATRIX. ' | 
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|  | 213 | DO 395 I= 1, NPAR | 
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|  | 214 | NDEX = I*(I-1)/2 | 
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|  | 215 | DO 394 J= 1, I-1 | 
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|  | 216 | NDEX = NDEX + 1 | 
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|  | 217 | 394 VHMAT(NDEX) = 0.0 | 
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|  | 218 | NDEX = NDEX +1 | 
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|  | 219 | G2I = G2(I) | 
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|  | 220 | IF (G2I .LE. ZERO)  G2I = 1.0 | 
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|  | 221 | 395 VHMAT(NDEX) = 2.0/G2I | 
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|  | 222 | 900 RETURN | 
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|  | 223 | END | 
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