# # Copyright 2003 Free Software Foundation, Inc. # # This file is part of GNU Radio # # GNU Radio is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 3, or (at your option) # any later version. # # GNU Radio is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with GNU Radio; see the file COPYING. If not, write to # the Free Software Foundation, Inc., 51 Franklin Street, # Boston, MA 02110-1301, USA. # """ Display numbers as strings using engineering notation. """ from __future__ import unicode_literals scale_factor = {} scale_factor['E'] = 1e18 scale_factor['P'] = 1e15 scale_factor['T'] = 1e12 scale_factor['G'] = 1e9 scale_factor['M'] = 1e6 scale_factor['k'] = 1e3 scale_factor['m'] = 1e-3 scale_factor['u'] = 1e-6 scale_factor['n'] = 1e-9 scale_factor['p'] = 1e-12 scale_factor['f'] = 1e-15 scale_factor['a'] = 1e-18 def num_to_str (n): '''Convert a number to a string in engineering notation. E.g., 5e-9 -> 5n''' m = abs(n) if m >= 1e9: return "%gG" % (n * 1e-9) elif m >= 1e6: return "%gM" % (n * 1e-6) elif m >= 1e3: return "%gk" % (n * 1e-3) elif m >= 1: return "%g" % (n) elif m >= 1e-3: return "%gm" % (n * 1e3) elif m >= 1e-6: return "%gu" % (n * 1e6) # where's that mu when you need it (unicode?) elif m >= 1e-9: return "%gn" % (n * 1e9) elif m >= 1e-12: return "%gp" % (n * 1e12) elif m >= 1e-15: return "%gf" % (n * 1e15) else: return "%g" % (n) def str_to_num (value): '''Convert a string in engineering notation to a number. E.g., '15m' -> 15e-3''' try: scale = 1.0 suffix = value[-1] if suffix in scale_factor: return float (value[0:-1]) * scale_factor[suffix] return float (value) except: raise RuntimeError ( "Invalid engineering notation value: %r" % (value,))