Hi, everyone I am a new sympy user and usually I work with Jupyter notebook. I would like construct a new symbolic class named FV (Four vector), I have made this
from sympy import * init_printing() class FV: def __init__(self,p0,p1,p2,p3): self.p0 = p0 self.p1 = p1 self.p2 = p2 self.p3 = p3 def __str__(self): return '({a},{b},{c},{d})'.format(a=self.p0, b=self.p1, c=self.p2, d=self.p3) def __repr__(self): return self.__str__() def __add__(self,other): p0,p1,p2,p3 = self.p0,self.p1,self.p2,self.p3 k0,k1,k2,k3 = other.p0,other.p1,other.p2,other.p3 return FV(p0+k0, p1+k1, p2+k2, p3+k3) def __mul__(self,other): p0,p1,p2,p3 = self.p0,self.p1,self.p2,self.p3 k0,k1,k2,k3 = other.p0,other.p1,other.p2,other.p3 return FV(p0*k0,-p1*k1,-p2*k2,-p3*k3) def __abs__(self): from sympy import sqrt p0,p1,p2,p3 = self.p0,self.p1,self.p2,self.p3 return sqrt(p0**2 - p1**2 - p2**2 - p3**2) def __eq__(self,other): return self.p0 == other.p0 and self.p1 == other.p1 and self.p2 == other.p2 and self.p3 == other.p3 def __neq__(self,other): return not self.__eq__(other) but this works while I use float or int python objects for the components in FV, when I use symbols I obtained p = {i:symbols('{{p^{a}}}'.format(a=i)) for i in range(4)} pmu = FV(p[0],p[1],p[2],p[3]) pmu ({p^0},{p^1},{p^2},{p^3}) this output do not used a init_printing(). Can someone help me please? -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/9264e591-442b-4c62-95ab-2b0d7810f0e9%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.