photon use
  p;;;;
 
 
  view x
  con pot x 1 fi;0.01
  vec x 1
  pause
  con wcrt x 1 fi;0.001
  con w1 x 1 fi;0.001
  pause
  view z
  con wcrt z 5 fi;0.01
  do kk=1,13
  con w1 z kk fi;0.01
  enddo
 
  enduse
 ************************************************************
  Group 1. Run TitLe
TEXT(Twisted-pipe grid; potential flow   :568
TITLE
 ************************************************************
  Groups 3, 4, 5  Grid Information
REAL(TWIST)
TWIST=5
NX=8; NY=6; NZ=12
BFC=T
NCRT=1
 
mesg(create cylindrical grid? y/n
READVDU(ANS,CHAR,Y)
IF(:ANS:.EQ.Y) THEN
 mesg(this q1 creates a twisted cylindrical grid
 REAL(XX,YY,ZZ,ZFAC,SNXX,CSXX,LITTLER,BIGR)
 REAL(TWOPI,XXC,YYC,ZZC,YYY,CSZZ,SNZZ)
 LITTLER=1.0; BIGR=1.0; TWOPI=2.0*3.14157
 GSET(D,NX,NY,NZ)
 NX
 NY
 NZ
 do KK=1,NZ+1
 KK
 ZFAC=TWIST*(KK-1)/NZ
 do II=1,NX+1
 XX=TWOPI*(II-1)/NX + ZFAC
 SNXX=SIN(XX)
 CSXX=COS(XX)
 do JJ=1,NY+1
 YY=LITTLER*(JJ-1)/NY
 XXC=YY*CSXX
 YYY=YY*SNXX
XC(II,JJ,KK)=XXC
YC(II,JJ,KK)=YYY
ZC(II,JJ,KK)=ZFAC
 enddo
 enddo
 enddo
ELSE
 mesg(read a grid file? y/n
 READVDU(ANS,CHAR,N)
 IF(:ANS:.EQ.Y) THEN
  + NX=12; NY=6; NZ=24
+ READCO(XYZ)
 ENDIF
ENDIF
XCYIZ(1,NZ,T)
VIEW(J,NY+1)
GVIEW(P,1,1,1);GDRAW
 ************************************************************
  Group 7. Variables: STOREd,SOLVEd,NAMEd
SOLVE(POT); SOLUTN(POT,Y,Y,Y,P,P,P)
STORE(U1,V1,W1,UCRT,VCRT,WCRT)
 ************************************************************
  Group 13. Boundary & Special Sources
PATCH(IN,LOW,1,NX,1,NY,1,1,1,1)
COVAL(IN,POT,1.E5,1.0)
 
PATCH(OUT,HIGH,1,NX,1,NY,NZ,NZ,1,1)
COVAL(OUT,POT,1.0,0)
 ************************************************************
  Group 15. Terminate Sweeps
LSWEEP  =    100; RESFAC  = 1.000E-06
 ************************************************************
  Group 16. Terminate Iterations
LITER(POT)=-200
 ************************************************************
  Group 19. EARTH Calls To GROUND Station
POTVEL=T
 ************************************************************
  Group 22. Monitor Print-Out
IZMON  =     NZ/2; TSTSWP  =      -1
PATCH(AXIS,PROFIL,1,1,1,1,1,NZ,1,1)
COVAL(AXIS,POT,0.0,0.0)
COVAL(AXIS,W1,0.0,0.0)