topic Re: Perfect numbers in SAS Programming

Perfect numbers

Sharatm9 — Tue, 28 Apr 2020 11:30:43 GMT

Can someone please help me answer this question.

Write code in SAS that allows one to write to a csv file a data set with all natural numbers less than a given parameter N as well as a boolean variable indicating if the number is perfect or not.

So the CSV must contain

1, False

2, False

6 True

Im a first time SAS user and I cant seem to go anywhere with this.

Re: Perfect numbers

PaigeMiller — Tue, 28 Apr 2020 11:36:58 GMT

Seems like a very difficult problem for a first-time user.

This paper can help: https://support.sas.com/resources/papers/proceedings15/3384-2015.pdf

Re: Perfect numbers

Sharatm9 — Tue, 28 Apr 2020 11:42:29 GMT

Yes pretty difficult. Will go through the paper. I think I did come across the paper earlier. Thank you

Re: Perfect numbers

Rick_SAS — Tue, 28 Apr 2020 12:55:47 GMT

You might want to recheck the statement of the problem. A common programming assignment is to determine whether a number is a perfect square. That only requires checking whether

ceil(sqrt(x))**2 = x

This is much easier than determining whether a number is perfect, which is an abstract property in number theory.

Re: Perfect numbers

Sharatm9 — Tue, 28 Apr 2020 13:01:28 GMT

Thank you for response, Sir. But the question is correct. It requires us to get first N (6) perfect numbers. (where the divisors adds upto to the number. the quoted example is 28[1,2,4,7,14])

Re: Perfect numbers

Rick_SAS — Tue, 28 Apr 2020 13:16:23 GMT

Okay. I don't know if your class discussed PROC FCMP, which enables you to define DATA step functions. If so, I recommend that you write an FCMP function that takes a number and computes whether it is perfect by finding the sum of all integer divisors. A short intro to PROC FCMP is at "Extending SAS: How to define new functions in PROC FCMP."

Re: Perfect numbers

ballardw — Tue, 28 Apr 2020 22:01:29 GMT

@Sharatm9 wrote:
Thank you for response, Sir. But the question is correct. It requires us to get first N (6) perfect numbers. (where the divisors adds upto to the number. the quoted example is 28[1,2,4,7,14])

Finding the first 6 of just about anything is likely to be much easier than an arbitrary N as indicated in your first post. So which is it, first 6 or first N?

Re: Perfect numbers

Sharatm9 — Tue, 28 Apr 2020 22:24:45 GMT

It the first 6.

Re: Perfect numbers

Kurt_Bremser — Wed, 29 Apr 2020 07:31:11 GMT

Given the limitations of SAS, only the first 7 perfect numbers can be calculated with numeric variables anyway (see https://en.wikipedia.org/wiki/Perfect_number and the continuing link https://oeis.org/A000396).