sum and product inside a program

03292016, 09:52 PM
Post: #1




sum and product inside a program
I got strange results in one of my programs and it appears that sum() and product() don't work correctly, if called inside a program.
Example: POLY(n,z) BEGIN LOCAL k; sum(z^k/k^n, 1, 3, 1); END; returns +inf for POLY(2,.1). But in CAS, from the command line, sum(0.1^k/k^2), returns .1026 . . . Similar problem with product inside a program. 

03292016, 11:57 PM
Post: #2




RE: sum and product inside a program
I could never get sum() to work right inside a program unless I made it a CAS program. This seems to do what you need:
#cas POLY(n,z):= BEGIN LOCAL k; sum(z^k/k^n,k,1,3,1); END; #end road 

03302016, 12:43 AM
Post: #3




RE: sum and product inside a program
Thanks! I'll try that.


05222017, 11:04 PM
Post: #4




RE: sum and product inside a program
Per Cyrille:
sum is sum(expr, var, reals...)... this program is missing an EXPORT and a k in the sum to work. EXPORT POLY(n,z) BEGIN LOCAL k; sum(z^k/k^n, k, 1, 3, 1); END; 

05242017, 01:53 PM
Post: #5




RE: sum and product inside a program
Yes, thanks for pointing this out   I noticed that I forgot the index variable k as soon as I started on the CAS version a while back. All is well.


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