def substract(a, b):
"""Returns the expression resultant of substracting terms a and b."""
a = Expression(a, no_vars_intended=True)
b = Expression(b, no_vars_intended=True)
if isanumber(a.expression) or isanumber(b.expression):
raise NonAlgebraicOperationError
if len(a.terms) > 1 or len(b.terms) > 1:
raise InvalidOperationError(a, b)
if TermOperations.getpower(
a.expression) is not TermOperations.getpower(
b.expression) or a.variables != b.variables:
result = a.expression + '-' + b.expression
return Expression.beautify(result)
a_coefficient = a.get_number(0, frac_to_number=True)
b_coefficient = b.get_number(0, frac_to_number=True)
result = str(num(a_coefficient) - num(b_coefficient))
result = if_assign(result == '1', "", result)
result = if_assign(result == '-1', "-", result)
result += "".join(a.variables) + '**' + str(
TermOperations.getpower(a.expression))
return Expression.beautify(result)
def add(a, b, non_algebraic=False):
"""Returns the expression resultant of adding terms a and b."""
a = Expression(a, no_vars_intended=True)
b = Expression(b, no_vars_intended=True)
if isanumber(a.expression) or isanumber(b.expression):
if non_algebraic is True:
return num(num(a.expression) + num(b.expression))
raise NonAlgebraicOperationError
if len(a.terms) > 1 or len(b.terms) > 1:
raise InvalidOperationError(a, b)
if TermOperations.getpower(
a.expression) is not TermOperations.getpower(
b.expression) or a.variables != b.variables:
operator = if_assign(b.expression.startswith('-'), '', '+')
return Expression.beautify(a.expression + operator + b.expression)
a_coefficient = a.get_number(0)
b_coefficient = b.get_number(0)
result = str(num(a_coefficient) + num(b_coefficient))
result = if_assign(result == '1', "", result)
result = if_assign(result == '-1', "-", result)
result += "".join(a.variables) + '**' + str(
TermOperations.getpower(a.expression))
if result.endswith('**1'):
result = result.replace('**1', '')
return Expression.beautify(result)
def multiply(a, b):
"""Multiplies terms a and b."""
a = Expression(a, no_vars_intended=True)
b = Expression(b, no_vars_intended=True)
power = str(
if_assign(
TermOperations.getpower(a.expression) >=
TermOperations.getpower(b.expression),
TermOperations.getpower(a.expression),
TermOperations.getpower(b.expression)))
variables = set(a.variables + b.variables)
if len(TermOperations.commonvars(a.expression, b.expression)) > 0:
power = str(
int(TermOperations.getpower(a.expression)) +
int(TermOperations.getpower(b.expression)))
power = if_assign(power == '1', '', power)
if power == '1':
return "".join(variables)
a_coefficient = a.get_number(0)
b_coefficient = b.get_number(0)
result = str(int(a_coefficient) *
int(b_coefficient)) + "".join(variables) + '**' + power
return Expression.beautify(result)
def divide(a, b):
a = Expression(a)
b = Expression(b)
variables = set(a.variables + b.variables)
power = '**' + str(
int(TermOperations.getpower(a.expression)) -
int(TermOperations.getpower(b.expression)))
power = if_assign(power == '**1', '', power)
if power == '**0':
return "/".join(variables)
a_coefficient = a.get_number(0)
b_coefficient = b.get_number(0)
result = str(num(
int(a_coefficient) / int(b_coefficient))) + "/".join(variables)
result = if_assign(power != '', '(' + result + ')' + power, result)
return Expression.beautify(result)
