PRINT-OUT from EARTH

Contents

1. Introduction and general advice
2. Use for the diagnosis of divergence
3. Output thinning
4. Use of line-printer contours and profiles
5. Print-out elicited by SPEDAT commands
6. Other topics

1. Introduction and general advice

It is hard to know in advance precisely what print-out will be required. Some users therefore call for much more than they are sure to need, just in case it will be found to be useful; but, in doing so, they create needless difficulties, burdening themselves with more paper or longer output files than they can possibly inspect.

Because of the ability easily to 'restart' a PHOENICS computation, it is best to call for only a small amount of output at first, concentrating perhaps on the 'residuals', and how they diminish with number of sweeps; and this should be viewed at the VDU, without recourse to the line printer. If the results of the computation are saved, by way of the SAVE=T setting in Group 24 (this is the default), it will always be possible to elicit desired output by making one more sweep with the appropriate settings in Groups 21, 22 and 23 (see AUTOPS).

Thus, a series of minimum-output runs may be made, by a succession of restarts, until it is judged that the solution is sufficiently converged to be interesting. Then a succession of single-sweep runs can be made, with various output options, until tables and plots containing the desired combination of information items, suitably displayed, have been elicited. Only at the end of this is it appropriate to cause the output actually to be printed.

2. Use for the diagnosis of divergence

When divergence occurs at the start of a run, printing out and inspecting the field values for the first two or three sweeps will often permit the cause to be discerned. For example, it may reveal that some variables have totally unrealistic values even at the start, possibly because of errors in coding introduced into GROUND; or the occurrence of low pressures near what is ostensibly an outflow boundary may reveal that inflow is occurring there.

3. Output thinning

It is rarely desirable that complete tables of field values are required to be printed; therefore, when fine-grid runs are being performed, a user who neglects the numerous print-out-control features of PHOENICS can impose a needless burden on himself. Attention is therefore drawn to the "output-thinning" variables NXPRIN, NYPRIN, NZPRIN, NTPRIN and NPRINT. In this connection, it may be convenient to make settings such as NXPRIN=NX/5 (actually the current defaults) in the SATELLITE; for these will keep the amount of print-out approximately the same, even when the values of NX, NY etc are changed.

The sizes of the output tables can also be limited by setting IXPRF, IYPRF, IZPRF, ISTPRF and ISWPRF to values in excess of 1, and those of IXPRL, IYPRL, IZPRL, ISTPRL, ISWPRL to values below NX, NY, NZ, LSTEP and LSWEEP respectively.

4. Use of line-printer contours and profiles

Finally, the use of PROFIL- and CONTUR -type patches, especially when the associated field values are printed out as numerical tables (see ITABL) can often provide all the numerical information which is needed. Then the regular field output can be dispensed with, by setting: OUTPUT (variable,N,,,,,).

5. Print-out elicited by SPEDAT commands

PHOENICS 3.3 provides examples of how SPEDAT commands can be used for eliciting information of various kinds, including:

1. the value of a particular variable at a particular cell;
2. the maximum and minimum values of a variable in the whole field, and their cell locations;
3. the total amount of a variable in the whole field
4. the mass-average value of a variable over the whole field
5. normalised and "power-lawed" values of a particular variable
6. how the total number of commands is indicated

These capabilities will now be discussed one-by-one, by reference to:

• the commands which must be placed in the Q1 file,
• how the print-out appears in the RESULT file; and
• the lines of coding in GREX3 which the commands activate.

a. The value of a particular variable

• Core-input library case 340 contains the following almost-self-explanatory lines:

  
    # the commands to print the value of v1 prevailing at
    ix=nx/2; iy=ny/2; iz=1
  SPEDAT(PRINT,COMMAND5,C,VALUE_V1)
  SPEDAT(PRINT,IXLOC,I,:NX/2:)
  SPEDAT(PRINT,IYLOC,I,:NY/2:)
  SPEDAT(PRINT,IZLOC,I,1)
  

  It is what follows VALUE_ in the fourth argument of the first line, and the contents of the fourth arguments of the three following lines, which determine what is printed.

• The print-out which actually appears in the result file is as follows (for case 340, with nx=10 and ny=10):

  
   Spedat print command is VALUE_V1
   At ix   =       5 iy      =       5  and iz =       1
     variable V1   has the
   VALUE   = 5.154015E-03
  

• The coding in group19 of GREX3 which produces this output is as follows:

  
         ELSEIF(MOD(ISTEP,NTPRIN).EQ.0) THEN
           CALL WRIT40('Spedat print command is '//command)
           IF( ....
           
           ELSEIF(COMMAND(1:5).EQ.'VALUE') THEN
             CALL GETSDI('PRINT','IXLOC',IXLOC)
             CALL GETSDI('PRINT','IYLOC',IYLOC)
             CALL GETSDI('PRINT','IZLOC',IZLOC)
             CALL GETVAL(COMMAND(7:10),IXLOC,IYLOC,IZLOC)
           ENDIF
         ENDIF
  

b. The maximum and minimum values of a variable

• Core-input library case 340 contains the following lines:

  
    # the command to print the minimum and maximum values of u1
  SPEDAT(PRINT,COMMAND3,C,MINMAX_U1)
  

  Evidently, it is what follows MINMAX_ in the fourth argument of SPEDAT which indicates the variable in question; and this time there is no need to specify a location, for where the minimum and maximum values are to be found will be worked by EARTH.

• The print-out appears as follows in the RESULT file:

  
   Spedat print command is MINMAX_U1
                     hilo3d called for U1
   Highest & lowest values of .......  U1
   highest = 3.913156E-02 lowest  =-3.992829E-02
   ixhigh  =       4 iyhigh  =       8 izhigh  =       1
   ixlow   =       6 iylow   =       3 izlow   =       1
  

• The coding in GREX3 which produces it is as follows:

  
         ELSEIF(COMMAND(1:6).EQ.'MINMAX') THEN
           CALL WRIT40('hilo3d called for '//COMMAND(8:11))
           CALL HILO3D(LBNAME(COMMAND(8:11)))
           CALL WRITBL
  

  Users accustomed to performing their own Fortran coding may care to note that HILO3D(LBNAME(name of 3D-stored variable)) is available for inclusion in their own coding.

c. The total amount of a variable in the whole field

• Core-input library case 340 contains the following lines:

  
    # the command to compute the total of temperature
  SPEDAT(PRINT,COMMAND1,C,TOTAL_TEMP)
  

  Evidently, it is what follows TOTAL_ in the fourth argument of SPEDAT which indicates the variable in question;

• The print-out appears as follows in the RESULT file:

  
   Spedat print command is TOTAL_TEMP
    total whole-domain amount of       TEMP
   TOTAL   = 1.930567E-03
  

• The coding in GREX3 which produces it is as follows:

  
         ELSEIF(COMMAND(1:5).EQ.'TOTAL') THEN
           CALL SUMALL(SUM,COMMAND(7:10))
           CALL WRIT40('total whole-domain amount of       '//
                       COMMAND(7:10))
           CALL WRIT1R('TOTAL   ',SUM)
           CALL WRITBL
  

d. The mass-average value of a variable in the whole field

• Core-input library case 340 contains the following lines: # the command to print the average value of c1 SPEDAT(PRINT,COMMAND4,C,AVE_C1)

  Evidently, it is what follows AVE_ in the fourth argument of SPEDAT which indicates the variable in question;

• The print-out appears as follows in the RESULT file:

  
   Spedat print command is AVE_C1
         mass-average value of         C1
   average = 6.982114E-01
  

• The coding in GREX3 which produces it is as follows:

  
         IF(COMMAND(1:3).EQ.'AVE') THEN
           CALL AVERAGE(AVE,COMMAND(5:8))
           CALL WRIT40
           ('mass-average value of         '//COMMAND(5:8))
           CALL WRIT1R('average ',AVE)
           CALL WRITBL
  

e. Normalised and "power-lawed" values of a particular variable

• Core-input library case 340 contains the following lines:

  
    # giving h1 the necessary four-character name
  NAME(H1)= TEMP
   
    # storing density because it is needed for computation of totals
  STORE(DEN1)
    # the command to compute the total of temperature
  SPEDAT(PRINT,COMMAND1,C,TOTAL_TEMP)
  
    # storing c1 as a place to put 
                  (temp - tempmin)/(tempmax - tempmin)**power
  STORE(C1)
    
    # the command to compute and store the above quantity
  SPEDAT(PRINT,COMMAND2,C,POW_TEMP_C1)
    
    # the power to be used
  SPEDAT(PRINT,POWER,R,0.5)
                                                               
  

  Evidently, it is what follows POW_ in the fourth argument of SPEDAT which indicates the variable in question;

• The print-out appears as follows in the RESULT file:

  
   Field Values of C1
   IY=  10   9.963E-01   8.697E-01   7.894E-01   3.253E-01
     C1  holds "power-lawed" values of TEMP
   power   = 5.000000E-01
  

• The coding in GREX3 which produces it is as follows:

  
         IF(COMMAND(1:3).EQ.'POW') THEN
  c.... do this before the istep test so that result is included in phi 
         CALL GETSDR('PRINT','POWER',POWER)
         IF(MOD(ISTEP,NTPRIN).EQ.0) THEN
           CALL WRIT40(COMMAND(10:13)//
                    'holds "power-lawed" values of '
                    //COMMAND(5:8))
           CALL WRIT1R('power   ',POWER)
         ENDIF  
         CALL PUT_POWER( COMMAND(5:8) , COMMAND(10:13),POWER )
         CALL WRITBL
  

f. how the total number of commands is indicated

• Core-input library case 340 contains the following lines:

  
    # the number of commands
  SPEDAT(PRINT,NUMBER,I,5)
  

  Evidently, it is the fourth argument of SPEDAT which tells EARTH how many print commands to look for.

• The number of SPEDAT print-out commands is not printed in the RESULT file:

• The coding in GREX3 which detects and uses the number of commands is as follows:

  
  c.... print-out elicited by SPEDAT('PRINT', ...  statements in Q1 
        IF(ISWEEP.EQ.FSWEEP) THEN
          IF(ISTEP.EQ.1) THEN
  c.... get number of special-print commands
            NUMSPPR=0
            CALL GETSDI('PRINT','NUMBER',NUMSPPR)
          ENDIF  
        ENDIF  
        IF(NUMSPPR.GT.0) THEN
  

6. Other topics

Print-out of stored variables, specification of

(see OUTPUT)

Print-out of tabular fields

(see XZPR)

Print-out of velocity

(see IURPRN)

Print-out time-step interval for

(see NPRMNT)

Print-out, sweep interval

(see NPRMON)

Print-outs

(see GROUPS 20-24)

Printing initial fields

(see INIFLD)

Printing text in EARTH and PHOTON output

(see TEXT)

Printing, first sweep for

(see ISWPRF)

Printing, first time step for

(see ISTPRF)

Printing, last sweep for

(see ISWPRL)

Printing, last time step for

(see ISTPRL)