GP_Image_Test/extern/swilk.f

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2024-01-29 09:19:57 -05:00
SUBROUTINE SWILK (INIT, X, N, N1, N2, A, W, PW, IFAULT)
C
C ALGORITHM AS R94 APPL. STATIST. (1995) VOL.44, NO.4
C
C Calculates the Shapiro-Wilk W test and its significance level
C
C IFAULT error code details from the R94 paper:
C - 0 for no fault
C - 1 if N1 < 3
C - 2 if N > 5000 (a non-fatal error)
C - 3 if N2 < N/2, so insufficient storage for A
C - 4 if N1 > N or (N1 < N and N < 20)
C - 5 if the proportion censored (N-N1)/N > 0.8
C - 6 if the data have zero range (if sorted on input)
C
INTEGER N, N1, N2, IFAULT
REAL X(*), A(*), PW, W
REAL C1(6), C2(6), C3(4), C4(4), C5(4), C6(3), C7(2)
REAL C8(2), C9(2), G(2)
REAL Z90, Z95, Z99, ZM, ZSS, BF1, XX90, XX95, ZERO, ONE, TWO
REAL THREE, SQRTH, QTR, TH, SMALL, PI6, STQR
REAL SUMM2, SSUMM2, FAC, RSN, AN, AN25, A1, A2, DELTA, RANGE
REAL SA, SX, SSX, SSA, SAX, ASA, XSX, SSASSX, W1, Y, XX, XI
REAL GAMMA, M, S, LD, BF, Z90F, Z95F, Z99F, ZFM, ZSD, ZBAR
C
C Auxiliary routines
C
REAL PPND, POLY
DOUBLE PRECISION ALNORM
C
INTEGER NCENS, NN2, I, I1, J
LOGICAL INIT, UPPER
C
DATA C1 /0.0E0, 0.221157E0, -0.147981E0, -0.207119E1,
* 0.4434685E1, -0.2706056E1/
DATA C2 /0.0E0, 0.42981E-1, -0.293762E0, -0.1752461E1,
* 0.5682633E1, -0.3582633E1/
DATA C3 /0.5440E0, -0.39978E0, 0.25054E-1, -0.6714E-3/
DATA C4 /0.13822E1, -0.77857E0, 0.62767E-1, -0.20322E-2/
DATA C5 /-0.15861E1, -0.31082E0, -0.83751E-1, 0.38915E-2/
DATA C6 /-0.4803E0, -0.82676E-1, 0.30302E-2/
DATA C7 /0.164E0, 0.533E0/
DATA C8 /0.1736E0, 0.315E0/
DATA C9 /0.256E0, -0.635E-2/
DATA G /-0.2273E1, 0.459E0/
DATA Z90, Z95, Z99 /0.12816E1, 0.16449E1, 0.23263E1/
DATA ZM, ZSS /0.17509E1, 0.56268E0/
DATA BF1 /0.8378E0/, XX90, XX95 /0.556E0, 0.622E0/
DATA ZERO /0.0E0/, ONE/1.0E0/, TWO/2.0E0/, THREE/3.0E0/
DATA SQRTH /0.70711E0/, QTR/0.25E0/, TH/0.375E0/, SMALL/1E-19/
DATA PI6 /0.1909859E1/, STQR/0.1047198E1/, UPPER/.TRUE./
C
PW = ONE
IF (W .GE. ZERO) W = ONE
AN = N
IFAULT = 3
NN2 = N/2
IF (N2 .LT. NN2) RETURN
IFAULT = 1
IF (N .LT. 3) RETURN
C
C If INIT is false, calculates coefficients for the test
C
IF (.NOT. INIT) THEN
IF (N .EQ. 3) THEN
A(1) = SQRTH
ELSE
AN25 = AN + QTR
SUMM2 = ZERO
DO 30 I = 1, N2
A(I) = PPND((REAL(I) - TH)/AN25,IFAULT)
SUMM2 = SUMM2 + A(I) ** 2
30 CONTINUE
SUMM2 = SUMM2 * TWO
SSUMM2 = SQRT(SUMM2)
RSN = ONE / SQRT(AN)
A1 = POLY(C1, 6, RSN) - A(1) / SSUMM2
C
C Normalize coefficients
C
IF (N .GT. 5) THEN
I1 = 3
A2 = -A(2)/SSUMM2 + POLY(C2,6,RSN)
FAC = SQRT((SUMM2 - TWO * A(1) ** 2 - TWO *
* A(2) ** 2)/(ONE - TWO * A1 ** 2 - TWO * A2 ** 2))
A(1) = A1
A(2) = A2
ELSE
I1 = 2
FAC = SQRT((SUMM2 - TWO * A(1) ** 2)/
* (ONE - TWO * A1 ** 2))
A(1) = A1
END IF
DO 40 I = I1, NN2
A(I) = -A(I)/FAC
40 CONTINUE
END IF
INIT = .TRUE.
END IF
IF (N1 .LT. 3) RETURN
NCENS = N - N1
IFAULT = 4
IF (NCENS .LT. 0 .OR. (NCENS .GT. 0 .AND. N .LT. 20)) RETURN
IFAULT = 5
DELTA = FLOAT(NCENS)/AN
IF (DELTA .GT. 0.8) RETURN
C
C If W input as negative, calculate significance level of -W
C
IF (W .LT. ZERO) THEN
W1 = ONE + W
IFAULT = 0
GOTO 70
END IF
C
C Check for zero range
C
IFAULT = 6
RANGE = X(N1) - X(1)
IF (RANGE .LT. SMALL) RETURN
C
C Check for correct sort order on range - scaled X
C
IFAULT = 7
XX = X(1)/RANGE
SX = XX
SA = -A(1)
J = N - 1
DO 50 I = 2, N1
XI = X(I)/RANGE
CCCCC IF (XX-XI .GT. SMALL) PRINT *,' ANYTHING'
SX = SX + XI
IF (I .NE. J) SA = SA + SIGN(1, I - J) * A(MIN(I, J))
XX = XI
J = J - 1
50 CONTINUE
IFAULT = 0
IF (N .GT. 5000) IFAULT = 2
C
C Calculate W statistic as squared correlation
C between data and coefficients
C
SA = SA/N1
SX = SX/N1
SSA = ZERO
SSX = ZERO
SAX = ZERO
J = N
DO 60 I = 1, N1
IF (I .NE. J) THEN
ASA = SIGN(1, I - J) * A(MIN(I, J)) - SA
ELSE
ASA = -SA
END IF
XSX = X(I)/RANGE - SX
SSA = SSA + ASA * ASA
SSX = SSX + XSX * XSX
SAX = SAX + ASA * XSX
J = J - 1
60 CONTINUE
C
C W1 equals (1-W) calculated to avoid excessive rounding error
C for W very near 1 (a potential problem in very large samples)
C
SSASSX = SQRT(SSA * SSX)
W1 = (SSASSX - SAX) * (SSASSX + SAX)/(SSA * SSX)
70 W = ONE - W1
C
C Calculate significance level for W (exact for N=3)
C
IF (N .EQ. 3) THEN
PW = PI6 * (ASIN(SQRT(W)) - STQR)
RETURN
END IF
Y = LOG(W1)
XX = LOG(AN)
M = ZERO
S = ONE
IF (N .LE. 11) THEN
GAMMA = POLY(G, 2, AN)
IF (Y .GE. GAMMA) THEN
PW = SMALL
RETURN
END IF
Y = -LOG(GAMMA - Y)
M = POLY(C3, 4, AN)
S = EXP(POLY(C4, 4, AN))
ELSE
M = POLY(C5, 4, XX)
S = EXP(POLY(C6, 3, XX))
END IF
IF (NCENS .GT. 0) THEN
C
C Censoring by proportion NCENS/N. Calculate mean and sd
C of normal equivalent deviate of W.
C
LD = -LOG(DELTA)
BF = ONE + XX * BF1
Z90F = Z90 + BF * POLY(C7, 2, XX90 ** XX) ** LD
Z95F = Z95 + BF * POLY(C8, 2, XX95 ** XX) ** LD
Z99F = Z99 + BF * POLY(C9, 2, XX) ** LD
C
C Regress Z90F,...,Z99F on normal deviates Z90,...,Z99 to get
C pseudo-mean and pseudo-sd of z as the slope and intercept
C
ZFM = (Z90F + Z95F + Z99F)/THREE
ZSD = (Z90*(Z90F-ZFM)+Z95*(Z95F-ZFM)+Z99*(Z99F-ZFM))/ZSS
ZBAR = ZFM - ZSD * ZM
M = M + ZBAR * S
S = S * ZSD
END IF
PW = REAL(ALNORM(DBLE((Y - M)/S), UPPER))
C
RETURN
END
DOUBLE PRECISION FUNCTION ALNORM(X, UPPER)
C
C EVALUATES THE TAIL AREA OF THE STANDARDIZED NORMAL CURVE FROM
C X TO INFINITY IF UPPER IS .TRUE. OR FROM MINUS INFINITY TO X
C IF UPPER IS .FALSE.
C
C NOTE NOVEMBER 2001: MODIFY UTZERO. ALTHOUGH NOT NECESSARY
C WHEN USING ALNORM FOR SIMPLY COMPUTING PERCENT POINTS,
C EXTENDING RANGE IS HELPFUL FOR USE WITH FUNCTIONS THAT
C USE ALNORM IN INTERMEDIATE COMPUTATIONS.
C
DOUBLE PRECISION LTONE,UTZERO,ZERO,HALF,ONE,CON,
$ A1,A2,A3,A4,A5,A6,A7,B1,B2,
$ B3,B4,B5,B6,B7,B8,B9,B10,B11,B12,X,Y,Z,ZEXP
LOGICAL UPPER,UP
C
C LTONE AND UTZERO MUST BE SET TO SUIT THE PARTICULAR COMPUTER
C
CCCCC DATA LTONE, UTZERO /7.0D0, 18.66D0/
DATA LTONE, UTZERO /7.0D0, 38.00D0/
DATA ZERO,HALF,ONE,CON /0.0D0,0.5D0,1.0D0,1.28D0/
DATA A1, A2, A3,
$ A4, A5, A6,
$ A7
$ /0.398942280444D0, 0.399903438504D0, 5.75885480458D0,
$ 29.8213557808D0, 2.62433121679D0, 48.6959930692D0,
$ 5.92885724438D0/
DATA B1, B2, B3,
$ B4, B5, B6,
$ B7, B8, B9,
$ B10, B11, B12
$ /0.398942280385D0, 3.8052D-8, 1.00000615302D0,
$ 3.98064794D-4, 1.98615381364D0, 0.151679116635D0,
$ 5.29330324926D0, 4.8385912808D0, 15.1508972451D0,
$ 0.742380924027D0, 30.789933034D0, 3.99019417011D0/
C
ZEXP(Z) = DEXP(Z)
C
UP = UPPER
Z = X
IF (Z .GE. ZERO) GOTO 10
UP = .NOT. UP
Z = -Z
10 IF (Z .LE. LTONE .OR. UP .AND. Z .LE. UTZERO) GOTO 20
ALNORM = ZERO
GOTO 40
20 Y = HALF * Z * Z
IF (Z .GT. CON) GOTO 30
C
ALNORM = HALF - Z * (A1- A2 * Y / (Y + A3- A4 / (Y + A5 + A6 /
$ (Y + A7))))
GOTO 40
C
30 ALNORM = B1* ZEXP(-Y)/(Z - B2 + B3/ (Z +B4 +B5/(Z -B6 +B7/
$ (Z +B8 -B9/ (Z +B10 +B11/ (Z + B12))))))
C
40 IF (.NOT. UP) ALNORM = ONE - ALNORM
RETURN
END
REAL FUNCTION PPND(P, IFAULT)
C
C ALGORITHM AS 111 APPL. STATIST. (1977), VOL.26, NO.1
C
C PRODUCES NORMAL DEVIATE CORRESPONDING TO LOWER TAIL AREA OF P
C REAL VERSION FOR EPS = 2 **(-31)
C THE HASH SUMS ARE THE SUMS OF THE MODULI OF THE COEFFICIENTS
C THEY HAVE NO INHERENT MEANINGS BUT ARE INCLUDED FOR USE IN
C CHECKING TRANSCRIPTIONS
C STANDARD FUNCTIONS ABS, ALOG AND SQRT ARE USED
C
C NOTE: WE COULD USE DATAPLOT NORPPF, BUT VARIOUS APPLIED
C STATISTICS ALGORITHMS USE THIS. SO WE PROVIDE IT TO
C MAKE USE OF APPLIED STATISTICS ALGORITHMS EASIER.
C
REAL ZERO, SPLIT, HALF, ONE
REAL A0, A1, A2, A3, B1, B2, B3, B4, C0, C1, C2, C3, D1, D2
REAL P, Q, R
INTEGER IFAULT
DATA ZERO /0.0E0/, HALF/0.5E0/, ONE/1.0E0/
DATA SPLIT /0.42E0/
DATA A0 / 2.50662823884E0/
DATA A1 / -18.61500062529E0/
DATA A2 / 41.39119773534E0/
DATA A3 / -25.44106049637E0/
DATA B1 / -8.47351093090E0/
DATA B2 / 23.08336743743E0/
DATA B3 / -21.06224101826E0/
DATA B4 / 3.13082909833E0/
DATA C0 / -2.78718931138E0/
DATA C1 / -2.29796479134E0/
DATA C2 / 4.85014127135E0/
DATA C3 / 2.32121276858E0/
DATA D1 / 3.54388924762E0/
DATA D2 / 1.63706781897E0/
C
IFAULT = 0
Q = P - HALF
IF (ABS(Q) .GT. SPLIT) GOTO 1
R = Q*Q
PPND = Q * (((A3*R + A2)*R + A1) * R + A0) /
* ((((B4*R + B3)*R + B2) * R + B1) * R + ONE)
RETURN
1 R = P
IF (Q .GT. ZERO)R = ONE - P
IF (R .LE. ZERO) GOTO 2
R = SQRT(-ALOG(R))
PPND = (((C3 * R + C2) * R + C1) * R + C0)/
* ((D2*R + D1) * R + ONE)
IF (Q .LT. ZERO) PPND = -PPND
RETURN
2 IFAULT = 1
PPND = ZERO
RETURN
END
REAL FUNCTION POLY(C, NORD, X)
C
C
C ALGORITHM AS 181.2 APPL. STATIST. (1982) VOL. 31, NO. 2
C
C CALCULATES THE ALGEBRAIC POLYNOMIAL OF ORDER NORED-1 WITH
C ARRAY OF COEFFICIENTS C. ZERO ORDER COEFFICIENT IS C(1)
C
REAL C(NORD)
POLY = C(1)
IF(NORD.EQ.1) RETURN
P = X*C(NORD)
IF(NORD.EQ.2) GOTO 20
N2 = NORD-2
J = N2+1
DO 10 I = 1,N2
P = (P+C(J))*X
J = J-1
10 CONTINUE
20 POLY = POLY+P
RETURN
END