Iterative / recursive program with multiple output ?

[sd_gaertner]

Hello,

I’m quite new to Mathcad and Mathcad Prime. I already looked for a solution in this forum and in the help files, but did not find anything suitable. Here’s my problem:

I defined a function f_next_s: Input s_n (current) -> Output s_n+1 (next).

Now I want to repeat this procedure n times, starting with s_1(given):

Step INPUT (s_cur) OUTPUT (s_pre)

1 s_1 s_2

2 s_2 s_3

3 s_3 …

… … …

n s_n s_n+1

AND

I want to store the values of s_1, s_2, … s_n+1 so that I can go on calculating with them.

Here is what I tried, but it doesn't work (it only gives out the first result, which is s_2):

Here ( http://communities.ptc.com/message/157701#157701 ) it says I should write the values in an array. But I can’t figure out how this works…

Can you please help me?

Best regards

Sebastian

[MikeArmstrong]

Can you upload the worksheet?

Mike

[sd_gaertner]

I thought it mitght be too confusing. But here it is.

There problem is situated at sheet 5 and 6.

Best regards

Sebastian

[MikeArmstrong]

I'm confused. The program you showed in your first post is not the same in your worksheet

Can you clearly indicate which function has the problem and list the expected results, sorry I am mad busy today and haven't got much spare time

Mike

[sd_gaertner]

OK, sorry. Let me explain:

The pogram in the mathcade file is the original one. It does the same as the programs in the pictures I posted.

All I did was to change the names of the variables before posting the pictures - I thought it would be easier to understand like that...

I can't adapt the worksheet right now. I will upload a better explained version tomorrow, if there is no solution by then.

Thank you anyway for your effort.

Sebastian

[Fred_Kohlhepp · Accepted solution]

I don't have Prime in front of me right now, but I think the answer to your problem is that you're not making an array in your program. I've enclosed a short file in version 14 that illustrates.

I hope this helps.

[sd_gaertner]

Hello again.

Fred, thank you for your detailled explanation. I think this is exactly what I need!

But now there is another problem:

I can not create a subscripted "i-1" like this

All I get in Mathcad Prime is a subscripted "i" minus the value 1

How can I fix this?

-------------------- EDIT --------------

OK, I got it.

I can use the shortcut key "[" to define the matrix.

That's it!
Thank you all very much

Message was edited by: Sebastian Distler

[RichardJ]

The last line should just be "s". If you return s[j then it will return only the element of s that corresponds to the current value of j (which is of course the last value).