CAS bug when calculating sum(1/n,n,1,medium_value)

[ftneek]

(10-10-2023 10:28 AM)parisse Wrote:  Like for integration, if you want to compute a numeric approximation of a sum, you should give an approx input, for example sum(1.0/n,n,1,10000). That's what you do in Home, without having to explicitly convert 1 to 1.0, because HOME does approx computations.

I tried sum(1.0/n,n,1,10000) as you entered in cas and home but it gave undef. I tried sigma notation in cas and home, home gave an approx solution while cas gave undef. I tried sum(1.0/n,n,1,2000000) in cas and home and it gave Psi(2000001)+euler_gamma (with comma separator in home). I tried with sigma notation in cas and home and approx lower bound, cas returned the exact answer again. Are you sure changing to approx input forces numeric computation?

Edit: actually what I tried was sum(1/n,n,1.0,10000), apologies. Changing to 1.0/n does indeed show a numeric calculation in cas, but home still gives undef (after changing n to X). But sum(1.0/n,n,1,2000000) still gave still gave an answer in terms of Psi in home and cas, even when trying 1.0/n.