147 lines
3.9 KiB
Python
147 lines
3.9 KiB
Python
# -*- coding: utf-8 -*-
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# PyMeeus: Python module implementing astronomical algorithms.
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# Copyright (C) 2018 Dagoberto Salazar
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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from math import floor
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"""
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.. module:: base
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:synopsis: Basic routines and constants used by the pymeeus module
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:license: GNU Lesser General Public License v3 (LGPLv3)
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.. moduleauthor:: Dagoberto Salazar
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"""
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TOL = 1e-10
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"""Internal tolerance being used by default"""
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def machine_accuracy():
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"""This function computes the accuracy of the computer being used.
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This function returns a tuple containing the number of significant bits in
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the mantissa of a floating number, and the number of significant digits in
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a decimal number.
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:returns: Number of significant bits, and of significant digits
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:rtype: tuple
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"""
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j = 0.0
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x = 2.0
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while x + 1.0 != x:
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j += 1.0
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x *= 2.0
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return (j, int(j * 0.30103))
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def get_ordinal_suffix(ordinal):
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"""Method to get the suffix of a given ordinal number, like 1'st',
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2'nd', 15'th', etc.
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:param ordinal: Ordinal number
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:type ordinal: int
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:returns: Suffix corresponding to input ordinal number
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:rtype: str
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:raises: TypeError if input type is invalid.
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>>> get_ordinal_suffix(40)
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'th'
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>>> get_ordinal_suffix(101)
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'st'
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>>> get_ordinal_suffix(2)
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'nd'
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>>> get_ordinal_suffix(19)
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'th'
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>>> get_ordinal_suffix(23)
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'rd'
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"""
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if not isinstance(ordinal, (int, float)):
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raise TypeError("Invalid input type")
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else:
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ordinal = int(floor(ordinal))
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unit = ordinal % 10
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if unit == 1 and ordinal != 11:
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return "st"
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elif unit == 2 and ordinal != 12:
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return "nd"
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elif unit == 3 and ordinal != 13:
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return "rd"
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else:
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return "th"
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def iint(number):
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"""This method behaves in the same way as the **INT()** function described
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by Meeus in his book: Greatest integer which is not greater than number.
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:param number: Number or expresion
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:type number: int, float
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:returns: Greatest integer which is not greater than number
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:rtype: int
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:raises: TypeError if input type is invalid.
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>>> iint(19)
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19
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>>> iint(19.95)
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19
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>>> iint(-2.4)
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-3
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"""
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if not isinstance(number, (int, float)):
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raise TypeError("Invalid input type")
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else:
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return int(floor(number))
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def main():
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# Let's define a small helper function
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def print_me(msg, val):
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print("{}: {}".format(msg, val))
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# Let's print the tolerance
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print_me("The default value for the tolerance is", TOL)
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# Find the accuracy of this computer
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j, d = machine_accuracy()
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print_me("Number of significant BITS in the mantissa\t", j)
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print_me("Number of significant DIGITS in a decimal number", d)
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print("")
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print_me("The suffix for ordinal 2 is", get_ordinal_suffix(2))
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print_me("The suffix for ordinal 11 is", get_ordinal_suffix(11))
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print_me("The suffix for ordinal 12 is", get_ordinal_suffix(12))
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print_me("The suffix for ordinal 13 is", get_ordinal_suffix(13))
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print_me("The suffix for ordinal 14 is", get_ordinal_suffix(14))
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print_me("The suffix for ordinal 16 is", get_ordinal_suffix(16))
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print_me("The suffix for ordinal 23 is", get_ordinal_suffix(23))
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if __name__ == "__main__":
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main()
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