CFD Online Discussion Forums - [ICEM] How to get vertex location from script?

Initially I worked around it by calculating where I had put each split and so on. After a while this became very annoying, so yesterday I made my own workaround.

The workaround requires to save the blocking (that you want to 'query') to file. In the blocking file, the coordinates of the vertices are also recorded, so using the vertex's ijk, I search through the entire blocking file.

Now, there are some shortcomings:

The current file has to be saved. If iterating this could lead to many file-writes => slow
Each time the function is called, the full blk is read again, again => slow (this could be fixed fairly easily if it's a problem for you - see comment in code)
The blk format is completely undocumented, so there is absolutely no guarantee that the naive logic I have implemented would always find the right place in the file. My geometry (on which i have tested) is very simple. If you find bugs and/or fixes please write back. In short the logic is:
- Read blocking file to memory;
- Get i,j,k of vertex;
- Find the line containing the string (tcl definition): "\{ $i $j $k \}";
- Split the line (by space (default));
- Return the first three items on the line (assuming they are the location).

There are two functions defined below, the first is a small helper routine to read a file into a variable using only one line. The second (get_vertex_location_from_blk) is where the parsing is done.

Code:

# Read a file

proc read_whole_file {file_name} {

        set fp [open "$file_name" r]

        set file_data [read $fp]

        close $fp

        return $file_data

}



# Read vertex location from file.

# © Adam Andersen Læssøe, Jan, 2014

# Feel free to use or expand in any way you want, but provide credit.

# Returns -1 if unsucsessful

proc get_vertex_location_from_blk {vertex_number blk_file} {

        # In the sample file I looked at the ijk was only present on the line also specifying the coordinates.

        set ijk [ic_hex_vertex_ijk $vertex_number]

        # Wrap in braces to ensure uniqueness (the ijk might have some 'modifier' like "17:1")

        set ijk "\{ $ijk \}"

        # Read in the whole file. Carefull: if this is to be iterated over, it may become slow. 

        # Consider rewriting to suit your needs, eg. by supplying the data as an input parameter, so it at least only has to read once.

        # file data

        set fd [read_whole_file $blk_file]

        set fd [split $fd "\n"]

        set n_lines [llength $fd]

        # set have_found_ijk 0

        set i 0

        while {[expr $i<$n_lines]} {

                # line data

                set ld [lindex $fd $i]

                #mess [lindex $fd $i]

                if {[string first $ijk $ld]!="-1"} {

                        # Below two lines do not work. ICEM throws: 'Error: wrong # args: should be "try"'

                        #try {return [lindices $ld {0 1 2}]} 

                        #on error {} {return -2}

                        # Be naive and hope for the best (could raise out of range exception)

                        return [lindices $ld {0 1 2}]

                }

                incr i

        }

        return -1

}