Note: Use only in the MuPAD Notebook Interface. This functionality does not run in MATLAB. |
If the sum
command
cannot compute a sum, MuPAD^{®} returns an unresolved sum. For example,
try to compute the following sum:
sum(exp(x)^(-x), x = 0..infinity)
The reasons MuPAD cannot compute the closed form of a particular sum are the same as the reasons for not computing an integral:
The antidifference does not exist in a closed form.
The antidifference exists, but MuPAD cannot find it.
MuPAD can find the antidifference on a larger computer, but runs out of time or memory on the available machine.
If MuPAD cannot compute a definite sum, try to approximate it numerically:
S := sum(exp(x)^(-x), x = 0..infinity); float(S)
If you know in advance that the antidifference cannot be computed
in a closed form, skip trying to calculate this sum symbolically.
For such expressions, call the numeric::sum
function to perform numeric
summation directly. Trying to calculate a symbolic sum, and then approximating
it numerically can be much slower than applying numeric summation
from the beginning:
numeric::sum(exp(x)^(-x), x = 0..infinity)