Actual source code: pdisplay.c
petsc-3.10.5 2019-03-28
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      2:  #include <petscsys.h>

      4: /*@C
      5:      PetscOptionsGetenv - Gets an environmental variable, broadcasts to all
      6:           processors in communicator from first.

      8:      Collective on MPI_Comm

     10:    Input Parameters:
     11: +    comm - communicator to share variable
     12: .    name - name of environmental variable
     13: -    len - amount of space allocated to hold variable

     15:    Output Parameters:
     16: +    flag - if not NULL tells if variable found or not
     17: -    env - value of variable

     19:   Level: advanced

     21:    Notes:
     22:     You can also "set" the environmental variable by setting the options database value
     23:     -name "stringvalue" (with name in lower case). If name begins with PETSC_ this is
     24:     discarded before checking the database. For example, PETSC_VIEWER_SOCKET_PORT would
     25:     be given as -viewer_socket_port 9000

     27:     If comm does not contain the 0th process in the MPIEXEC it is likely on
     28:     many systems that the environmental variable will not be set unless you
     29:     put it in a universal location like a .chsrc file

     31: @*/
     32: PetscErrorCode  PetscOptionsGetenv(MPI_Comm comm,const char name[],char env[],size_t len,PetscBool  *flag)
     33: {
     35:   PetscMPIInt    rank;
     36:   char           *str,work[256];
     37:   PetscBool      flg = PETSC_FALSE,spetsc;

     40:   /* first check options database */
     41:   PetscStrncmp(name,"PETSC_",6,&spetsc);

     43:   PetscStrcpy(work,"-");
     44:   if (spetsc) {
     45:     PetscStrcat(work,name+6);
     46:   } else {
     47:     PetscStrcat(work,name);
     48:   }
     49:   PetscStrtolower(work);
     50:   if (env) {
     51:     PetscOptionsGetString(NULL,NULL,work,env,len,&flg);
     52:     if (flg) {
     53:       if (flag) *flag = PETSC_TRUE;
     54:     } else { /* now check environment */
     55:       PetscMemzero(env,len*sizeof(char));

     57:       MPI_Comm_rank(comm,&rank);
     58:       if (!rank) {
     59:         str = getenv(name);
     60:         if (str) flg = PETSC_TRUE;
     61:         if (str && env) {PetscStrncpy(env,str,len);}
     62:       }
     63:       MPI_Bcast(&flg,1,MPIU_BOOL,0,comm);
     64:       MPI_Bcast(env,len,MPI_CHAR,0,comm);
     65:       if (flag) *flag = flg;
     66:     }
     67:   } else {
     68:     PetscOptionsHasName(NULL,NULL,work,flag);
     69:   }
     70:   return(0);
     71: }

     73: /*
     74:      PetscSetDisplay - Tries to set the X windows display variable for all processors.
     75:                        The variable PetscDisplay contains the X windows display variable.

     77: */
     78: static char PetscDisplay[256];

     80: static PetscErrorCode PetscWorldIsSingleHost(PetscBool  *onehost)
     81: {
     83:   char           hostname[256],roothostname[256];
     84:   PetscMPIInt    localmatch,allmatch;
     85:   PetscBool      flag;

     88:   PetscGetHostName(hostname,256);
     89:   PetscMemcpy(roothostname,hostname,256);
     90:   MPI_Bcast(roothostname,256,MPI_CHAR,0,PETSC_COMM_WORLD);
     91:   PetscStrcmp(hostname,roothostname,&flag);

     93:   localmatch = (PetscMPIInt)flag;

     95:   MPIU_Allreduce(&localmatch,&allmatch,1,MPI_INT,MPI_LAND,PETSC_COMM_WORLD);

     97:   *onehost = (PetscBool)allmatch;
     98:   return(0);
     99: }

    102: PetscErrorCode  PetscSetDisplay(void)
    103: {
    105:   PetscMPIInt    size,rank;
    106:   PetscBool      flag,singlehost=PETSC_FALSE;
    107:   char           display[sizeof(PetscDisplay)];
    108:   const char     *str;

    111:   PetscOptionsGetString(NULL,NULL,"-display",PetscDisplay,sizeof(PetscDisplay),&flag);
    112:   if (flag) return(0);

    114:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
    115:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

    117:   PetscWorldIsSingleHost(&singlehost);

    119:   str = getenv("DISPLAY");
    120:   if (!str) str = ":0.0";
    121: #if defined(PETSC_HAVE_X)
    122:   flag = PETSC_FALSE;
    123:   PetscOptionsGetBool(NULL,NULL,"-x_virtual",&flag,NULL);
    124:   if (flag) {
    125:     /*  this is a crude hack, but better than nothing */
    126:     PetscPOpen(PETSC_COMM_WORLD,NULL,"pkill -9 Xvfb","r",NULL);
    127:     PetscSleep(1);
    128:     PetscPOpen(PETSC_COMM_WORLD,NULL,"Xvfb :15 -screen 0 1600x1200x24","r",NULL);
    129:     PetscSleep(5);
    130:     str  = ":15";
    131:   }
    132: #endif
    133:   if (str[0] != ':' || singlehost) {
    134:     PetscStrncpy(display,str,sizeof(display));
    135:   } else if (!rank) {
    136:     PetscGetHostName(display,sizeof(display));
    137:     PetscStrlcat(display,str,sizeof(display));
    138:   }
    139:   MPI_Bcast(display,sizeof(display),MPI_CHAR,0,PETSC_COMM_WORLD);
    140:   PetscMemcpy(PetscDisplay,display,sizeof(PetscDisplay));

    142:   PetscDisplay[sizeof(PetscDisplay)-1] = 0;
    143:   return(0);
    144: }

    146: /*
    147:      PetscGetDisplay - Gets the display variable for all processors.

    149:   Input Parameters:
    150: .   n - length of string display

    152:   Output Parameters:
    153: .   display - the display string

    155:   Options Database:
    156: +  -display <display> - sets the display to use
    157: -  -x_virtual - forces use of a X virtual display Xvfb that will not display anything but -draw_save will still work. Xvfb is automatically
    158:                 started up in PetscSetDisplay() with this option

    160: */
    161: PetscErrorCode  PetscGetDisplay(char display[],size_t n)
    162: {

    166:   PetscStrncpy(display,PetscDisplay,n);
    167:   return(0);
    168: }