fourier index to angstrom resolution

fpix2res.py

#!/usr/bin/env python

import click

@click.command()
@click.argument('fourier_pixel_extent', required=False)
@click.argument('angstroms_per_pixel', required=False)
@click.argument('box_size', required=False)
@click.option('-fpix',
              '--fourier_pixel_extent',
              help='Fourier pixel extent that you would like to convert into a resolution',
              prompt='Fourier pixel extent: ',
              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 fpix2res(fourier_pixel_extent, angstroms_per_pixel, box_size):
    """
    Convert extent of signal into fourier space into a resolution value in angstroms
    """
    fraction_of_nyquist = float(fourier_pixel_extent) / (0.5 * box_size)
    nyquist_frequency_angstroms = 1.0 / (2.0 * float(angstroms_per_pixel))
    spatial_frequency_angstroms = fraction_of_nyquist * nyquist_frequency_angstroms
    resolution_angstroms = 1.0 / spatial_frequency_angstroms
    click.echo(f'Resolution (Å): {resolution_angstroms}')
    return resolution_angstroms


if __name__ == '__main__':
    fpix2res()