Actual source code: pdisplay.c
petsc-3.7.1 2016-05-15
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      2: #include <petscsys.h>

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

     10:      Collective on MPI_Comm

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

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

     21:   Level: advanced

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

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

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

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

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

     59:       MPI_Comm_rank(comm,&rank);
     60:       if (!rank) {
     61:         str = getenv(name);
     62:         if (str) flg = PETSC_TRUE;
     63:         if (str && env) {PetscStrncpy(env,str,len);}
     64:       }
     65:       MPI_Bcast(&flg,1,MPIU_BOOL,0,comm);
     66:       MPI_Bcast(env,len,MPI_CHAR,0,comm);
     67:       if (flag) *flag = flg;
     68:     }
     69:   } else {
     70:     PetscOptionsHasName(NULL,NULL,work,flag);
     71:   }
     72:   return(0);
     73: }

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

     79: */
     80: static char PetscDisplay[256];

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

     92:   PetscGetHostName(hostname,256);
     93:   PetscMemcpy(roothostname,hostname,256);
     94:   MPI_Bcast(roothostname,256,MPI_CHAR,0,PETSC_COMM_WORLD);
     95:   PetscStrcmp(hostname,roothostname,&flag);

     97:   localmatch = (PetscMPIInt)flag;

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

    101:   *onehost = (PetscBool)allmatch;
    102:   return(0);
    103: }

    108: PetscErrorCode  PetscSetDisplay(void)
    109: {
    111:   PetscMPIInt    size,rank;
    112:   PetscBool      flag,singlehost=PETSC_FALSE;
    113:   char           display[sizeof(PetscDisplay)];
    114:   const char     *str;

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

    120:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
    121:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

    123:   PetscWorldIsSingleHost(&singlehost);

    125:   str = getenv("DISPLAY");
    126:   if (!str) str = ":0.0";
    127: #if defined(PETSC_HAVE_X)
    128:   flag = PETSC_FALSE;
    129:   PetscOptionsGetBool(NULL,NULL,"-x_virtual",&flag,NULL);
    130:   if (flag) {
    131:     /*  this is a crude hack, but better than nothing */
    132:     PetscPOpen(PETSC_COMM_WORLD,NULL,"pkill -9 Xvfb","r",NULL);
    133:     PetscSleep(1);
    134:     PetscPOpen(PETSC_COMM_WORLD,NULL,"Xvfb :15 -screen 0 1600x1200x24","r",NULL);
    135:     PetscSleep(5);
    136:     str  = ":15";
    137:   }
    138: #endif
    139:   if (str[0] != ':' || singlehost) {
    140:     PetscStrncpy(display,str,sizeof(display));
    141:   } else if (!rank) {
    142:     size_t len;
    143:     PetscGetHostName(display,sizeof(display));
    144:     PetscStrlen(display,&len);
    145:     PetscStrncat(display,str,sizeof(display)-len-1);
    146:   }
    147:   MPI_Bcast(display,sizeof(display),MPI_CHAR,0,PETSC_COMM_WORLD);
    148:   PetscMemcpy(PetscDisplay,display,sizeof(PetscDisplay));

    150:   PetscDisplay[sizeof(PetscDisplay)-1] = 0;
    151:   return(0);
    152: }

    156: /*
    157:      PetscGetDisplay - Gets the display variable for all processors.

    159:   Input Parameters:
    160: .   n - length of string display

    162:   Output Parameters:
    163: .   display - the display string

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

    170: */
    171: PetscErrorCode  PetscGetDisplay(char display[],size_t n)
    172: {

    176:   PetscStrncpy(display,PetscDisplay,n);
    177:   return(0);
    178: }