You have to explicitly tell that indexed variables can overlap and intersect. Maybe this code fetches you the desired result, Try to split the sum into parts
dF_dxi = x[i] + sp.Sum(x[j], (j, 1, i-1)) + sp.Sum(x[j], (j, i+1, C)) + x[i] #outpur: (Sum(x[j], (j, 1, i - 1)) + Sum(x[j], (j, i + 1, C)))*x[i] + x[i]**2 On Tuesday, 28 January 2025 at 15:10:22 UTC+5:30 [email protected] wrote: > Hi, does anyone know how to properly integrate this indexed sum for an xi > term that is also present in the sum indexed by j below? > ``` > i, j, C = sp.symbols('i, j, k, C', integer=True) > x = sp.IndexedBase('x') > dF_dxi = x[i] + sp.Sum(x[j], (j, 1, C)) > Fxi = sp.integrate(dF_dxi, x[i]) > # result: x[i]**2/2 + x[i]*Sum(x[j], (j, 1, C)) > ``` > It seems the integration does not realize that one of the xj terms in the > sum is an xi since it assumes the indices don't ever intersect even though > these are both defined as integers. > > > -- 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/sympy/d63042b5-7e10-4aa7-a472-7462d5c05473n%40googlegroups.com.
