Fortran to Matlab GOTO

Hi everyone, I want to translate a Fortran Code to Matlab and I'm stuck in this part of the code specifically with the goto statement. Here is the part of the code I can't understand how to translate it.

      DO 11 J=2,N1
      Q10=Q1
      V10=V1
      IF(DU(J).EQ.0) GO TO 15    
      IF(DB(J).EQ.0) GO TO 515   

      QPU=0.
      QPB=0.
      V2=0.5*(V(J)+V(J-1)+Q(J)-Q(J-1))/(1.+0.5*ET*DX)
      Q2=Q(J-1)+V2-V(J-1)
      V1=V2
      Q1=Q(J)-V1+V(J)   
      DU3=DU(J)-V2*DT             

      DB3=DB(J)+V2*DT           
      IF(DU3.LE.0.) GO TO 50    
      IF(DB3.LE.0.) GO TO 550 
      GO TO 20

   15 QPU=Q(J-1)-Q(J)-V(J)-V(J-1)
      IF(QPU.GT.0.) GO TO 30    
      V2=0.
      Q2=Q(J-1)-V(J-1)
      V1=0.
      Q1=Q(J)+V(J)
      GO TO 111

   30 QPU=0.                   
      V2=0.5*(V(J)+V(J-1)+Q(J)-Q(J-1))/(1.+0.5*ET*DX)
      Q2=Q(J-1)+V2-V(J-1)
      V1=V2
      Q1=Q(J)-V1+V(J)
      DU3=-D2U(J)-V2*DT  
      DB3=DB(J)+V2*DT
      IF(DU3.GE.0.) THEN
      DU(J)=DU3      
      D2U(J)=0.      
      IF(DB3.LT.0.) GO TO 550
      ELSE
      DU(J)=0.      
      D2U(J)=ABS(DU3)     
      ENDIF
      DB(J)=DB3
      D2B(J)=0.
      GO TO 111

   20 DU(J)=DU3
      DB(J)=DB3
      D2U(J)=0.
      D2B(J)=0.
      GO TO 111

   50 DU(J)=0.
      D2U(J)=ABS(DU3)
      DB(J)=DB3
      D2B(J)=0.
      GO TO 111

515 QPB=Q(J-1)-Q(J)-V(J)-V(J-1)
    IF(QPB.LT.0.) GO TO 530

      V2=0.
      Q2=Q(J-1)-V(J-1)
      V1=0.
      Q1=Q(J)+V(J)
      GO TO 111

530 QPB=0.
    V2=0.5*(V(J)+V(J-1)+Q(J)-Q(J-1))/(1.+0.5*ET*DX)
    Q2=Q(J-1)+V2-V(J-1)
    V1=V2
    Q1=Q(J)-V1+V(J)
    DB3=-D2B(J)+V2*DT
    DU3=DU(J)-V2*DT
    IF(DB3.GE.0.) THEN
    DB(J)=DB3
    D2B(J)=0.
    IF(DU3.LT.0.) GO TO 50
    ELSE
    DB(J)=0.
    D2B(J)=ABS(DB3)
    ENDIF
    DU(J)=DU3
    D2U(J)=0.
    GO TO 111

550 DB(J)=0.
    D2B(J)=ABS(DB3)
    DU(J)=DU3
    D2U(J)=0.

111 Q(J-1)=Q10+Q2-Q(J-1)
    V(J-1)=V10+V2-V(J-1)

      U(J)=U(J)+V2*DT

      UPU(J)=U(J)-D2U(J)

      UPB(J)=U(J)+D2B(J)  
      11 CONTINUE

Thank you very much,

Carlos

Answer 1

[dpb]

First branch; similar for the rest altho may be more rework and need some other refactorization than just simple IF...ELSE...ENDIF branching

       DO 11 J=2,N1                             DO 11 j=2,n1
         Q10=Q1                                   Q10=Q1
         V10=V1                                   V10=V1
         IF(DU(J).EQ.0) GO TO 15                  IF(DU(J)<>0) then
         ...                                        ... 
   15    CONTINUE                                 ENDIF 
         QPU=Q(J-1)-Q(J)-V(J)-V(J-1)              QPU=Q(J-1)-Q(J)-V(J)-V(J-1)  % target line 15
         ...                                      ...

Probably the simpler is one of either

a) rewrite the functional requirements in Matlab syntax rather than try to transliterate, or

b) turn the existing Fortran into a mex file and call from Matlab.

Answer 2

[Yao Li]

There are many options:

1. Create a function for each destination of "goto". ie. Create a fuction for 111
2. Copy and paste the corresponding portion to where it is called
3. Create a classdef and include all the functions in the classdef script