Runtime error in shiftnd

[rhysaph]

Here is my code:

from image_registration import chi2_shift
from image_registration.fft_tools import shift

# -- Looping over subimages --

image_data1 = fits.getdata(sys.argv[1], ext=x)
image_data2 = fits.getdata(sys.argv[2], ext=x)
noise = np.zeros_like(image_data1,dtype=np.float)
                                                        
xoff, yoff, exoff, eyoff = chi2_shift(image_data1, image_data2, noise, return_error=True, upsample_factor='auto')
shifted_image_data2 = shift.shiftnd(image_data2, -yoff, -xoff)

and here is the runtime error:

  File "./subtractor_registration.py", line 128, in <module>
    shifted_image_data2 = shift.shiftnd(image_data2, -yoff, -xoff)
  File "/home/blah/site-packages/image_registration/fft_tools/shift.py", line 103, in shiftnd
    for dim,(off,nx) in enumerate(zip(offset,data.shape))],
TypeError: zip argument #1 must support iteration

It runs without error for shift.shift2d but produces a very shifted image for two almost aligned images.

[keflavich]

You've specified the arguments incorrectly. Look at the help for shiftnd:

Signature: shift.shiftnd(data, offset, phase=0, nthreads=1, use_numpy_fft=False, return_abs=False, return_real=True)
Docstring:
FFT-based sub-pixel image shift.
Will turn NaNs into zeros

Shift Theorem:

.. math::
    FT[f(t-t_0)](x) = e^{-2 \pi i x t_0} F(x)


Parameters
----------
data : np.ndarray
    Data to shift
offset : (int,)*ndim
    Offsets in each direction.  Must be iterable.
phase : float
    Phase, in radians

The offset must be an iterable. You should use shiftnd(image_data2, (-yoff, -xoff))

[cosmicoder]

Hi, I had the same TypeError of "zip argument #1 must support iteration". From the Quick Example section of the docs I pulled the general application - corrected_image2 = shift.shiftnd(offset_image, -yoff, -xoff)

As you pointed out, the argument has to be (-yoff,-xoff) i.e. a tuple. Can you correct the docs?

[keflavich]

@cosmicoder this issue was correct in 21f5a53. Where are you seeing the outdated documentation?

[cosmicoder]

@cosmicoder this issue was correct in 21f5a53. Where are you seeing the outdated documentation?

Found it here - https://image-registration.readthedocs.io/en/latest/# is this an outdated doc version?

[keflavich]

yes, it looks like readthedocs is not building any more

[keflavich]

the infrastructure is out of date. Thanks for pointing this out @cosmicoder ; it's going to take a bit of work to refactor this.