[求助] 完全新手，求救大神。能不能帮我看看这是什么意思

C     User Unit Operation Model (or Report) Subroutine for USER
C     
      SUBROUTINE MEMBRANE (NSIN,    NINFI,  SIN1,   SIN2,    SIN3,
     2                   SIN4,    SINFI,  NSOUT,  NINFO,   SOUT1,
     3                   SOUT2,   SOUT3,  SOUT4,  SINFO,   NSUBS,
     4                   IDXSUB,  ITYPE,  NINT,   INT,     NREAL,
     5                   REAL,    IDS,    NPO,    NBOPST,  NIWORK,
     6                   IWORK,   NWORK,  WORK,   NSIZE,   SIZE,
     7                   INTSIZ,  LD)
C
      IMPLICIT NONE
C
C     DECLARE VARIABLES USED IN DIMENSIONING
C
      INTEGER NSUBS, NINT,  NPO,   NIWORK,NWORK,
     +        NSIZE
C
#include "ppexec_user.cmn"
      EQUIVALENCE (RMISS, USER_RUMISS)
      EQUIVALENCE (IMISS, USER_IUMISS)
C
C
C
#include "dms_ncomp.cmn"
C
C     THIS SUBROUTINE WILL SPLIT AN INLET TO TWO OUTLETS
C
C     RETRIEVE THE SLPIT FACTOR
C
C     DECLARE ARGUMENTS
C
      INTEGER IDXSUB(NSUBS),ITYPE(NSUBS), INT(NINT),
     +        IDS(2,13),    NBOPST(6,NPO),
     +        IWORK(NIWORK),INTSIZ(NSIZE),NSIN,  NINFI,
     +        NSOUT, NINFO, NREAL, LD,    I
      REAL*8 SIN1(1),      SIN2(1),      SIN3(1),
     +       SIN4(1),      SOUT1(1),     SOUT2(1),
     +       SOUT3(1),     SOUT4(1),     WORK(NWORK),
     +       SIZE(NSIZE),  SINFI, SINFO
C
C     DECLARE LOCAL VARIABLES
C
      INTEGER IMISS
      REAL*8 REAL(NREAL),  RMISS, SPLIT
C
C     BEGIN EXECUTABLE CODE