IgorWriter

Write Igor Binary Wave (.ibw) or Igor Text (.itx) files from numpy array

Features

• Compatible with multi-dimensional arrays (up to 4 dimensions)
• Supported numpy data types: uint, int, float, complex, bool, str, bytes, datetime64
• Data units (IgorWave.set_datascale)
• Dimension scaling (IgorWave.set_dimscale)
• Dimension labels (IgorWave.set_dimlabel)
• Wave notes (IgorWave.set_note)
• Dependency formula (IgorWave.set_formula)

Installation

$ pip install igorwriter

Usage

Basic usage

import numpy as np 
from igorwriter import IgorWave 

array = np.array([1,2,3,4,5,6]) 

# make IgorWave objects 
wave = IgorWave(array, name='mywave') 
wave2 = IgorWave(array.astype(np.float32), name='mywave2') 

# save data
wave.save('mywave.ibw') 
wave.save_itx('mywave.itx')

with open('multi_waves.itx', 'w') as fp: 
    # Igor Text files can contain multiples waves per file 
    wave.save_itx(fp)
    wave2.save_itx(fp)

Data units, dimension scaling

wave.set_datascale('DataUnit') 
wave.set_dimscale('x', 0, 0.01, 's')

A two-dimensional array with dimension labels

a2 = np.random.random((10, 3)) 
wave = IgorWave(a2, name='wave2d') 

# you may set optional dimension labels 
wave.set_dimlabel(0, -1, 'points') # label for entire rows 
wave.set_dimlabel(1, -1, 'values') # label for entire columns 
wave.set_dimlabel(1, 0, 'ValueA') # label for column 0 
wave.set_dimlabel(1, 1, 'ValueB') # label for column 1 
wave.set_dimlabel(1, 2, 'ValueC') # label for column 2 
wave.save('my2dwave.ibw')

You can append arbitrary Igor commands to Igor Text files.

wave = IgorWave([1, 4, 9], name='wave0') 
with open('wave0.itx', 'w') as fp: 
    wave.save_itx(fp) 

fp.write("X Display 'wave0'\n")

Unicode support

From igorwriter 0.5.0, IgorWave stores texts with utf-8 encoding. If you use Igor Pro 6 or older and want to use non-ascii characters, set unicode=False when calling IgorWave(). It will fall back to system text encoding (Windows-1252, Shift JIS, etc.).

Wave Names

There are restrictions on object names in IGOR. From v0.2.0, this package deals with illegal object names.

# This will issue a RenameWarning, and the name will be automatically changed.
wave = IgorWave(array, name='wave:0', on_errors='fix')
print(wave.name)  # wave_0

# This will raise an InvalidNameError.
wave = IgorWave(array, name='wave:0', on_errors='raise')

Pint integration

If Pint Quantity objects are passed to IgorWave, data units will be set automatically.

import pint 
ureg = pint.UnitRegistry() 
w = IgorWave([3, 4] * ureg.meter / ureg.second, name='wave_with_units')

w.save_itx('wave_with_units.itx')
print(open('wave_with_units.itx', 'r').read())
# ...
# X SetScale d,0,0,"m / s",'wave_with_units' 
# X SetScale /P x,0.0,1.0,"",'wave_with_units'

Pandas integration

You can easily export DataFrame objects with convenience functions.

from igorwriter import utils 
utils.dataframe_to_itx(df, 'df.itx') # all Series are exported in one file 
waves = utils.dataframe_to_ibw(df, prefix='df_bin') # each Series is saved in a separate file, <prefix>_<column>.ibw 
print(waves) # dictionary of generated IgorWaves
# {'col1': <IgorWave 'col1' at 0x...>, 'col2': ...}

IgorWriter tries to convert index info on pandas.Series objects in following manners.

• If the index is evenly-spaced, wave dimension scaling is set accordingly.
• Index names are interpreted as the dimension labels.

Notes on Image Plots

Image Plot in IGOR and imshow in matplotlib use different convention for x and y axes:

• Rows as x, columns as y (IGOR)
• Columns as x, rows as y (Matplotlib)

Thus, image parameter was introduced in save() and save_itx() methods. If you use e.g.

wave.save('path.ibw', image=True)

plt.imshow and Image Plot will give the same results.

The image=True option transposes rows and columns of the underlying array, but does not swap data units, dimension scaling, etc. (You need to change them manually).

Changelog

v0.6.0 (2024-01-13)

• Wave note support
• Dependency formula support

v0.5.0 (2023-07-08)

• UTF-8 as default encoding. You can instead use system text encoding by setting unicode=False to IgorWave().
• Automatic conversion from pandas index to dimension scaling.
• Exporting 64-bit integer waves (requires Igor Pro 7 or later).
• BUG FIX: Igor Text files created from np.bool_ arrays were broken.

v0.4.1 (2023-07-02)

• Added support for np.str_ and np.bytes_ arrays.
• Automatic type conversion for np.object_ arrays.
• Added support for dimension scaling (IgorWave.set_simlabel).

v0.3.0 (2019-11-16)

• Added utils.dict_to_{ibw, itx}
• Set datascale automatically for pint Quantity object.
• Added support for np.datetime64 array.

v0.2.3 (2019-11-09)

• Added support for 64-bit integers (by automatically casting onto 32-bit integers on save).

v0.2.0 (2019-11-08)

• Added utilities for pandas (utils.dataframe_to_{ibw, itx} ).
• Added unittest scripts.
• Added wave name validator.
• BUG FIX: long (> 3 bytes) units for dimension scaling were ignored in save_itx()
• IgorWriter now uses system locale encoding rather than ASCII (the default behavior of IGOR Pro prior to ver. 7.00)