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SUBROUTINE SMATRIX%(proc_id)s(P,ANS)
C
%(info_lines)s
C
C MadGraph5_aMC@NLO for Madevent Version
C
C Returns amplitude squared summed/avg over colors
c and helicities
c for the point in phase space P(0:3,NEXTERNAL)
C
%(process_lines)s
C
use DiscreteSampler
IMPLICIT NONE
C
C CONSTANTS
C
Include 'genps.inc'
Include 'maxconfigs.inc'
Include 'nexternal.inc'
Include 'maxamps.inc'
INTEGER NCOMB
PARAMETER ( NCOMB=%(ncomb)d)
INTEGER NGRAPHS
PARAMETER (NGRAPHS=%(ngraphs)d)
INTEGER NDIAGS
PARAMETER (NDIAGS=%(ndiags)d)
INTEGER THEL
PARAMETER (THEL=NCOMB)
C
C ARGUMENTS
C
REAL*8 P(0:3,NEXTERNAL),ANS
c
c global (due to reading writting)
c
LOGICAL GOODHEL(NCOMB)
INTEGER NTRY
common/BLOCK_GOODHEL/NTRY,GOODHEL
C
C LOCAL VARIABLES
C
INTEGER NHEL(NEXTERNAL,NCOMB)
REAL*8 T,MATRIX%(proc_id)s
REAL*8 R,SUMHEL,TS(NCOMB)
INTEGER I,IDEN
INTEGER IPROC,JC(NEXTERNAL),II
REAL*8 HWGT, XTOT, XTRY, XREJ, XR, YFRAC(0:NCOMB)
INTEGER IDUM, NGOOD, IGOOD(NCOMB), JHEL, J, JJ
REAL XRAN1
EXTERNAL XRAN1
C
C GLOBAL VARIABLES
C
DOUBLE PRECISION AMP2(MAXAMPS), JAMP2(0:MAXFLOW)
COMMON/TO_AMPS/ AMP2, JAMP2
CHARACTER*101 HEL_BUFF
COMMON/TO_HELICITY/ HEL_BUFF
REAL*8 POL(2)
COMMON/TO_POLARIZATION/ POL
INTEGER ISUM_HEL
LOGICAL MULTI_CHANNEL
COMMON/TO_MATRIX/ISUM_HEL, MULTI_CHANNEL
%(define_iconfigs_lines)s
DATA IDUM /-1/
DATA XTRY, XREJ, NGOOD /0,0,0/
SAVE YFRAC, IGOOD, JHEL
%(helicity_lines)s
%(den_factor_line)s
C ----------
C BEGIN CODE
C ----------
NTRY=NTRY+1
DO I=1,NEXTERNAL
JC(I) = +1
ENDDO
IF (multi_channel) THEN
DO I=1,NDIAGS
AMP2(I)=0D0
ENDDO
JAMP2(0)=%(ncolor)d
DO I=1,INT(JAMP2(0))
JAMP2(I)=0D0
ENDDO
ENDIF
ANS = 0D0
WRITE(HEL_BUFF,'(20I5)') (0,I=1,NEXTERNAL)
DO I=1,NCOMB
TS(I)=0d0
ENDDO
! If the helicity grid status is 0, this means that it is not yet initialized.
IF (ISUM_HEL.EQ.0.or.(DS_get_dim_status('Helicity').eq.0)) THEN
DO I=1,NCOMB
IF (GOODHEL(I) .OR. NTRY .LE. MAXTRIES.OR.(ISUM_HEL.NE.0)) THEN
T=MATRIX%(proc_id)s(P ,NHEL(1,I),JC(1))
DO JJ=1,nincoming
IF(POL(JJ).NE.1d0.AND.NHEL(JJ,I).EQ.INT(SIGN(1d0,POL(JJ)))) THEN
T=T*ABS(POL(JJ))
ELSE IF(POL(JJ).NE.1d0)THEN
T=T*(2d0-ABS(POL(JJ)))
ENDIF
ENDDO
IF (ISUM_HEL.NE.0) then
call DS_add_entry('Helicity',I,T)
endif
ANS=ANS+DABS(T)
TS(I)=T
ENDIF
ENDDO
IF(NTRY.EQ.(MAXTRIES+1)) THEN
call reset_cumulative_variable() ! avoid biais of the initialization
ENDIF
IF (ISUM_HEL.NE.0) then
! We set HEL_PICKED to -1 here so that later on, the call to DS_add_point in dsample.f does not add anything to the grid since it was already done here.
HEL_PICKED = -1
! For safety, hardset the helicity sampling jacobian to 0.0d0 to make sure it is not .
hel_jacobian = 1.0d0
IF(DS_get_dim_status('Helicity').eq.1) then
! If we finished the initialization we can update the grid so as to start sampling over it.
! However the grid will now be filled by dsample with different kind of weights (including pdf, flux, etc...) so by setting the grid_mode of the reference grid to 'initialization' we make sure it will be overwritten (as opposed to 'combined') by the running grid at the next update.
CALL DS_UPDATE_GRID('Helicity')
CALL DS_SET_GRID_MODE('Helicity','init')
endif
ELSE
JHEL = 1
IF(NTRY.LE.MAXTRIES)THEN
DO I=1,NCOMB
IF (.NOT.GOODHEL(I) .AND. (TS(I).GT.ANS*LIMHEL/NCOMB)) THEN
GOODHEL(I)=.TRUE.
NGOOD = NGOOD +1
IGOOD(NGOOD) = I
print *,'Adding good helicity ',I,TS(I)/ANS
ENDIF
ENDDO
ENDIF
IF(NTRY.EQ.MAXTRIES)THEN
ISUM_HEL=MIN(ISUM_HEL,NGOOD)
ENDIF
endif
ELSE !RANDOM HELICITY
C The helicity configuration was chosen already by genps and put in a common block defined in genps.inc.
I = HEL_PICKED
T=MATRIX%(proc_id)s(P ,NHEL(1,I),JC(1))
DO JJ=1,nincoming
IF(POL(JJ).NE.1d0.AND.NHEL(JJ,I).EQ.INT(SIGN(1d0,POL(JJ)))) THEN
T=T*ABS(POL(JJ))
ELSE IF(POL(JJ).NE.1d0)THEN
T=T*(2d0-ABS(POL(JJ)))
ENDIF
ENDDO
c Always one helicity at a time
ANS = T
c Include the Jacobian from helicity sampling
ANS = ANS * hel_jacobian
WRITE(HEL_BUFF,'(20i5)')(NHEL(II,I),II=1,NEXTERNAL)
ENDIF
IF (ISUM_HEL .NE. 1.or.(HEL_PICKED.eq.-1)) THEN
R=XRAN1(IDUM)*ANS
SUMHEL=0d0
DO I=1,NCOMB
SUMHEL=SUMHEL+TS(I)
IF(R.LT.SUMHEL)THEN
WRITE(HEL_BUFF,'(20i5)')(NHEL(II,I),II=1,NEXTERNAL)
ANS=DSIGN(ANS,TS(I))
GOTO 10
ENDIF
ENDDO
10 CONTINUE
ENDIF
IF (MULTI_CHANNEL) THEN
XTOT=0D0
DO I=1,NDIAGS
XTOT=XTOT+AMP2(I)
ENDDO
IF (XTOT.NE.0D0) THEN
%(set_amp2_line)s
ELSE
ANS=0D0
ENDIF
ENDIF
ANS=ANS/DBLE(IDEN)
END
REAL*8 FUNCTION MATRIX%(proc_id)s(P,NHEL,IC)
C
%(info_lines)s
C
C Returns amplitude squared summed/avg over colors
c for the point with external lines W(0:6,NEXTERNAL)
C
%(process_lines)s
C
IMPLICIT NONE
C
C CONSTANTS
C
INTEGER NGRAPHS
PARAMETER (NGRAPHS=%(ngraphs)d)
include 'genps.inc'
include 'nexternal.inc'
include 'maxamps.inc'
INTEGER NWAVEFUNCS, NCOLOR
PARAMETER (NWAVEFUNCS=%(nwavefuncs)d, NCOLOR=%(ncolor)d)
REAL*8 ZERO
PARAMETER (ZERO=0D0)
COMPLEX*16 IMAG1
PARAMETER (IMAG1=(0D0,1D0))
INTEGER NAMPSO, NSQAMPSO
PARAMETER (NAMPSO=%(nAmpSplitOrders)d, NSQAMPSO=%(nSqAmpSplitOrders)d)
LOGICAL CHOSEN_SO_CONFIGS(NSQAMPSO)
DATA CHOSEN_SO_CONFIGS/%(chosen_so_configs)s/
SAVE CHOSEN_SO_CONFIGS
C
C ARGUMENTS
C
REAL*8 P(0:3,NEXTERNAL)
INTEGER NHEL(NEXTERNAL), IC(NEXTERNAL)
C
C LOCAL VARIABLES
C
INTEGER I,J,M,N
COMPLEX*16 ZTEMP
REAL*8 DENOM(NCOLOR), CF(NCOLOR,NCOLOR)
COMPLEX*16 AMP(NGRAPHS), JAMP(NCOLOR,NAMPSO)
COMPLEX*16 W(18,NWAVEFUNCS)
C Needed for v4 models
COMPLEX*16 DUM0,DUM1
DATA DUM0, DUM1/(0d0, 0d0), (1d0, 0d0)/
C
C FUNCTION
C
INTEGER SQSOINDEX%(proc_id)s
C
C GLOBAL VARIABLES
C
Double Precision amp2(maxamps), jamp2(0:maxflow)
common/to_amps/ amp2, jamp2
include 'coupl.inc'
C
C COLOR DATA
C
%(color_data_lines)s
C ----------
C BEGIN CODE
C ----------
%(helas_calls)s
%(jamp_lines)s
MATRIX%(proc_id)s = 0.D0
DO M = 1, NAMPSO
DO I = 1, NCOLOR
ZTEMP = (0.D0,0.D0)
DO J = 1, NCOLOR
ZTEMP = ZTEMP + CF(J,I)*JAMP(J,M)
ENDDO
DO N = 1, NAMPSO
IF (CHOSEN_SO_CONFIGS(SQSOINDEX%(proc_id)s(M,N))) THEN
MATRIX%(proc_id)s = MATRIX%(proc_id)s + ZTEMP*DCONJG(JAMP(I,N))/DENOM(I)
ENDIF
ENDDO
ENDDO
ENDDO
%(amp2_lines)s
Do I = 1, NCOLOR
DO M = 1, NAMPSO
DO N = 1, NAMPSO
IF (CHOSEN_SO_CONFIGS(SQSOINDEX%(proc_id)s(M,N))) THEN
Jamp2(i)=Jamp2(i)+DABS(DBLE(Jamp(i,m)*dconjg(Jamp(i,n))))
ENDIF
enddo
enddo
Enddo
END
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