resolution in angstroms to fourier index

res2fpix.py

#!/usr/bin/env python

import click

@click.command()
@click.argument('resolution_angstroms', required=False)
@click.argument('angstroms_per_pixel', required=False)
@click.argument('box_size', required=False)
@click.option('-res',
              '--resolution_angstroms',
              help='Resolution in angstroms that you would like to convert into a fourier pixel extent',
              prompt='Resolution in Angstroms: ',
              type=float)
@click.option('-apix',
              '--angstroms_per_pixel',
              help='Pixel size in Angstroms',
              prompt='Pixel size in Angstroms: ',
              type=float,)
@click.option('-b',
              '--box_size',
              help='Box size in pixels',
              prompt='Box size in pixels: ',
              type=int)
def res2fpix(resolution_angstroms, angstroms_per_pixel, box_size):
    """
    Convert a resolution in angstroms into the distance from the origin in fourier space for a given pixel size and
    box size
    """
    spatial_frequency_angstroms = 1.0 / float(resolution_angstroms)
    nyquist_frequency_angstroms = 1.0 / (2.0 * float(angstroms_per_pixel))
    fraction_of_nyquist = spatial_frequency_angstroms / nyquist_frequency_angstroms
    fourier_pixel_extent = fraction_of_nyquist * (0.5 * box_size)
    click.echo(f'Fourier pixel extent (px): {fourier_pixel_extent}')
    return fourier_pixel_extent


if __name__ == '__main__':
    res2fpix()