Mapytex/pymath/polynomDeg2.py

229 lines
7.0 KiB
Python

#!/usr/bin/env python
# encoding: utf-8
from .polynom import Polynom
from .expression import Expression
from .operator import op
from .random_expression import RdExpression
from math import sqrt
__all__ = ["Polynom_deg2"]
class Polynom_deg2(Polynom):
""" Degree 2 polynoms
Child of Polynom with some extra tools
"""
@classmethod
def random(self, coefs_form = ["{c}", "{b}", "{a}"], conditions = [], letter = "x"):
""" Create a 2nd degree poly from coefs_form ans conditions
:param coefs_form: list of forms (one by coef) (ascending degree sorted)
:param conditions: condition on variables
:param letter: the letter for the polynom
"""
if len(coefs_form) != 3:
raise ValueError("Polynom_deg2 have to be degree 2 polynoms, they need 3 coefficients, {} are given".format(len(coefs_form)))
form = str(coefs_form)
# On créé les valeurs toutes concaténées dans un string
coefs = RdExpression(form, conditions)()
# On "parse" ce string pour créer les coefs
coefs = [eval(i) if type(i)==str else i for i in eval(coefs)]
# Création du polynom
return Polynom_deg2(coefs = coefs, letter = letter)
def __init__(self, coefs = [0, 0, 1], letter = "x"):
if len(coefs) < 3 or len(coefs) > 4:
raise ValueError("Polynom_deg2 have to be degree 2 polynoms, they need 3 coefficients, {} are given".format(len(coefs)))
if coefs[2] == 0:
raise ValueError("Polynom_deg2 have to be degree 2 polynoms, coefficient of x^2 can't be 0")
Polynom.__init__(self, coefs, letter)
@property
def a(self):
return self._coef[2]
@property
def b(self):
return self._coef[1]
@property
def c(self):
return self._coef[0]
@property
def delta(self):
"""Compute the discriminant expression
:returns: discriminant expression
>>> P = Polynom_deg2([1,2,3])
>>> P.delta
-8
>>> for i in P.delta.explain():
... print(i)
2^{ 2 } - 4 \\times 3 \\times 1
4 - 4 \\times 3
4 - 12
-8
"""
return Expression([self.b, 2, op.pw, 4, self.a, self.c, op.mul, op.mul, op.sub]).simplify()
@property
def alpha(self):
""" Compute alpha the abcisse of the extremum
>>> P = Polynom_deg2([1,2,3])
>>> P.alpha
< Fraction -1 / 3>
>>> for i in P.alpha.explain():
... print(i)
\\frac{ - 2 }{ 2 \\times 3 }
\\frac{ -2 }{ 6 }
\\frac{ ( -1 ) \\times 2 }{ 3 \\times 2 }
\\frac{ -1 }{ 3 }
"""
return Expression([self.b, op.sub1, 2, self.a, op.mul, op.div]).simplify()
@property
def beta(self):
""" Compute beta the extremum of self
>>> P = Polynom_deg2([1,2,3])
>>> P.beta
< Fraction 2 / 3>
>>> for i in P.beta.explain(): # Ça serait bien que l'on puisse enlever des étapes maintenant...
... print(i)
3 \\times \\frac{ -1 }{ 3 }^{ 2 } + 2 \\times \\frac{ -1 }{ 3 } + 1
3 \\times \\frac{ 1 }{ 9 } + \\frac{ -2 }{ 3 } + 1
\\frac{ 1 }{ 3 } + \\frac{ -2 }{ 3 } + 1
\\frac{ -1 }{ 3 } + 1
\\frac{ 2 }{ 3 }
"""
return self(self.alpha).simplify()
def roots(self, after_coma = 2):
""" Compute roots of the polynom
/!\ Can't manage exact solution because of pymath does not handle sqare root yet
# TODO: Pymath has to know how to compute with sqare root |mar. févr. 24 18:40:04 CET 2015
>>> P = Polynom_deg2([1, 1, 1])
>>> P.roots()
[]
>>> P = Polynom_deg2([1, 2, 1])
>>> P.roots()
[-1.0]
>>> P = Polynom_deg2([-1, 0, 1])
>>> P.roots()
[-1.0, 1.0]
"""
if self.delta > 0:
self._roots = [round((-self.b - sqrt(self.delta))/(2*self.a),after_coma), round((-self.b + sqrt(self.delta))/(2*self.a),after_coma)]
elif self.delta == 0:
self._roots = [round(-self.b /(2*self.a), after_coma)]
else:
self._roots = []
return self._roots
def tbl_sgn_header(self):
""" Return header of the sign line for tkzTabLine"""
if self.delta > 0:
return "{$-\\infty$, " + str(min(self.roots())) + " , " + str( max(self.roots())) + " , $+\\infty$}"
elif self.delta == 0:
return "{$-\\infty$, " + str(self.roots()[0]) + " , $+\\infty$}"
else:
return "{$-\\infty$, $+\\infty$}"
def tbl_sgn(self):
""" Return the sign line for tkzTabLine
>>> P = Polynom_deg2([2, 5, 2])
>>> print(P.tbl_sgn())
\\tkzTabLine{, +, z, -, z , +,}
>>> P = Polynom_deg2([2, 1, -2])
>>> print(P.tbl_sgn())
\\tkzTabLine{, -, z, +, z , -,}
>>> P = Polynom_deg2([1, 2, 1])
>>> print(P.tbl_sgn())
\\tkzTabLine{, +, z, +,}
>>> P = Polynom_deg2([0, 0, -2])
>>> print(P.tbl_sgn())
\\tkzTabLine{, -, z, -,}
>>> P = Polynom_deg2([1, 0, 1])
>>> print(P.tbl_sgn())
\\tkzTabLine{, +,}
>>> P = Polynom_deg2([-1, 0, -1])
>>> print(P.tbl_sgn())
\\tkzTabLine{, -,}
"""
if self.delta > 0:
if self.a > 0:
return "\\tkzTabLine{, +, z, -, z , +,}"
else:
return "\\tkzTabLine{, -, z, +, z , -,}"
elif self.delta == 0:
if self.a > 0:
return "\\tkzTabLine{, +, z, +,}"
else:
return "\\tkzTabLine{, -, z, -,}"
else:
if self.a > 0:
return "\\tkzTabLine{, +,}"
else:
return "\\tkzTabLine{, -,}"
def tbl_variation(self, limits = False):
"""Return the variation line for tkzTabVar
:param limit: Display or not limits in tabular
>>> P = Polynom_deg2([1,2,3])
>>> print(P.tbl_variation())
\\tkzTabVar{+/{}, -/{$\\frac{ 2 }{ 3 }$}, +/{}}
>>> print(P.tbl_variation(limits = True))
\\tkzTabVar{+/{$+\\infty$}, -/{$\\frac{ 2 }{ 3 }$}, +/{$+\\infty$}}
"""
beta = self.beta
if limits:
if self.a > 0:
return "\\tkzTabVar{+/{$+\\infty$}, -/{$" + str(beta) + "$}, +/{$+\\infty$}}"
else:
return "\\tkzTabVar{-/{$-\\infty$}, +/{$" + str(beta) + "$}, -/{$-\\infty$}}"
else:
if self.a > 0:
return "\\tkzTabVar{+/{}, -/{$" + str(beta) + "$}, +/{}}"
else:
return "\\tkzTabVar{-/{}, +/{$" + str(beta) + "$}, -/{}}"
if __name__ == '__main__':
# from .render import txt
# with Expression.tmp_render(txt):
# P = Polynom_deg2([2, 3, 4])
# print(P)
# print("Delta")
# for i in P.delta.simplify():
# print(i)
import doctest
doctest.testmod()
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