tec_util

Utilities for working with Tecplot datafiles, targeting Python and the command line.

Overview

Starting with the 2017 R1 release, Tecplot 360EX ships with a Python API that largely eliminates the need for macro files. This software provides a Python module and an associated set of command line bindings for several common operations that I use to implement using macro files.

Command-Line Summary

tec_util --help                              # Command summary
tec_util info     infile                     # Print zone/variable/timepoint info
tec_util to_ascii infile [outfile]           # Convert datafile to ASCII format
tec_util to_plt   infile [outfile]           # Convert datafile to PLT format
tec_util slice    slices.py infile [outfile] # Extract slices from surface zones
tec_util export   layout.lay [outdir]        # Export all pages in layout to png
tec_util diff     new old [outfile]          # Compute new-old, write to out

Python API Summary

import tec_util
tec_util.export_pages(output_dir, prefix)
tec_util.slice_surfaces(slice_file, datafile_in, datafile_out)
tec_util.difference_datasets(datafile_new, datafile_old, datafile_out)

Currently, the Python API consists of three functions that reside in the tec_util module. These functions follow a similar API to their command line counterparts. All functions accept pathnames as input and generate new datafiles as output. I chose this approach because returning a new, logically independent dataset from a function is not possible without adding a new frame to the global layout, which may be an undesireable side effect. Therefore, tec_util utilizes a less efficient file-based API but guarantees the state of the tecplot runtime after a function is called is the same as before the call.

To Do

• Make slice_surfaces take list of tuples; parse slices.py as part of the CLI.

Requirements

• Python 3.4+
• Tecplot 360EX 2017 R2+ (w/ TecPLUS for PyTecplot)

Installation

Install via pip

The simplest installation method is to use pip to install directly from GitHub:

pip install git+git://github.com/flying-tiger/tec_util.git

This will install the master branch into your site-packages along with the latest version of PyTecplot from PyPI.

Manual Install

Alternatively, you can manually clone and install the package:

# Do this once
git clone <install_path>

# Put this in your .bashrc or similar
export TECUTIL_ROOT=<install_path>
export PYTHONPATH="$TECUTIL_ROOT:$PYTHON_PATH"
alias tec_util="python3 -m tec_util"

If you use envrionment modules, a modulefile is provided that will perform the envrionment configuration. Simply create symlink to the modulefile from somewhere on the module search path and load the module. For example, to use the ~/privatemodules directory:

# Do this once
mkdir -p ~/privatemodules
ln -s <path_to_repo>/modulefile ~/privatemodules/tec_util

# Put this in your .bashrc or similar
module load use.own
module load tec_util

PyTecplot Configuration

Even if you do the automated install, PyTecplot will require additional configuration of the envrionment. Full installation instructions are here. When properly installed, you should be able to do the following:

>> python3 -c "import tecplot; print(tecplot.layout.active_page())"
Page: ""

DYLD_LIBRARY_PATH, PyTecplot and tec_util

As detailed at the link above, PyTecplot relies on LD_LIBRARY_PATH and DYLD_LIBRARY_PATH to locate the Tecplot libraries installed on your system. This presents a problem when using tec_util on macOS because starting with El Capitan, macOS scrubs DYLD_LIBRARY_PATH from the environment before spawning subprocesses of /bin/bash and other "protected" programs. In practice, this means tec_util cannot be used in a script unless it is source'd or hard-coded with the location of the Tecplot libraries. This also prevent use of tec_util as as step in a Makefile since each line of a recipe is executed in an isolated subshell.

A work around for this is to define a function that shadows tec_util and explicitly sets the DYLD_LIBRARY_PATH variable before calling tec_util. It's an ugly solution, but it allows scripts and Makefiles to be written without hardcoded, platform-specific logic.

export TECBIN=<path_to_tecplot_libs>
function tec_util { DYLD_LIBRARY_HOME="$TECBIN" "$(which tec_util)" "$@"; }
export -f tec_util