POST_SUB

Use

To generate an output file or process the results programmatically, in other words, for real-time animation or plotting.

 <Post_UserAPI
     usrsub_param_string = "USER()"
     usrsub_dll_name     = "ms_csubdll"
     usrsub_fnc_name     = "POST_SUB"
/>

Format

Fortran Calling Syntax

SUBROUTINE POST_SUB (TIME, IFLAG, INTERPOLATION_FLAG)

C/C++ Calling Syntax

void STDCALL POST_SUB (double *time, double *par, int *npar, int *iflag, int *endflag, int *errflg)

Python Calling Syntax

def POST_SUB(time, par, npar, iflag, endflag):
    return errflg

MATLAB Calling Syntax

function errflg = POST_SUB(time, par, npar, iflag, endflag)

Attributes

TIME: [double precision]; The current simulation time.
IFLAG: [logical]; The initialization flag.
INTERPOLATION_FLAG: [logical]; The interpolation flag.

Example

The following example writes the X,Y,Z and Euler parameters for each rigid body in the model at each time step into a results XML file:

<Post_UserAPI
     usrsub_param_string = "USER()"
     interpreter         = "Python"
     script_name         = "/post_sub.py"
     usrsub_fnc_name     = "POST_SUB"
 />

The contents of post_sub.py are:

NULL = 0
fout = NULL
nparts = 0
partids = []

def POST_SUB(time, par, npar, iflag, endflag):
    global NULL
    global fout
    global nparts

    if endflag!=0:
        # Wrap up
        if fout!=NULL:
            fout.write("</MultiBodyResults>\n")
            fout.close()
            del fout
            fout = NULL
        if partids!=[]:
            del partids
            partids  = []
        return 0
    if iflag!=0:
        outfile = py_gtonam()
        outfile += "_res.xml"
        fout = open(outfile,"w")
        # XML Header
        fout.write("<?xml version=\"1.0\"?>\n")
        fout.write("<MultiBodyResults>\n")
        # Get ID information
        nparts = py_getnumid("PART")
        if nparts!=0:
            [partids, err_flg] = py_getidlist("PART",nparts)
            if err_flg <0:
                return err_flg
    else:
            if fout==NULL: 
                print "Output file was not opened, no results will be written\n"
                return -1
            fout.write("\t<Results\n")
            fout.write("\t\ttime    = \"%f\">\n"% time)
            # Rigid Body
            for i in range(nparts):
              [grndflag, info] = py_modfnc("Body_Rigid", partids[i],"IsGround")
              if grndflag=="FALSE":
                  states = py_get_post_states("PART", partids[i])
                  fout.write("\t\t<RigidBody\n")
                  fout.write("\t\t\tid      = \"%d\"\n"% partids[i])
                  fout.write("\t\t\tx       = \"%-11.8G\"\n"% states[0])
                  fout.write("\t\t\ty       = \"%-11.8G\"\n"% states[1])
                  fout.write("\t\t\tz       = \"%-11.8G\"\n"% states[2])
                  fout.write("\t\t\te0      = \"%-11.8G\"\n"% states[3])
                  fout.write("\t\t\te1      = \"%-11.8G\"\n"% states[4])
                  fout.write("\t\t\te2      = \"%-11.8G\"\n"% states[5])
                  fout.write("\t\t\te3      = \"%-11.8G\"\n"% states[6])
                  fout.write("\t\t/>\n")
    return 0

Comments

The Post_Sub is called by MotionSolve at the same time steps when data is written to the MRF file during the simulation.
From within Post_Sub, you may also call the other available utility subroutines, such as MODFNC.