"IF" function with undefined "OTHERWISE" item?

[Briscoz]

Hi,
Please, could you help me? I have problem with "IF" function. I have function named "f1" and "f2".
f1:=0..10
f2:=0..10
Sum of these function cannot be greater that 10. If the sum is greater, then function is undefined.

I tried do that by the help of the "IF" function.
if(f1+f2<10,f1+f2,0)
But there is "OTHERWISE" item. I use "0", but would like to use "UNDEFINED", or something like that.

It is possible to do that?

Thanks

 

[IRstuff]

You can specific a text output using UNDEFINED in quotes.

TTFN

FAQ731-376

 

[jghrist]

But the funcion won't work because you can't compare the results of adding two range variables to a scalar. Try creating a vector and comparing each element.

 

[pstuckey]

What you may be looking for is NaN (no quotes), which will define a result as Not a Number.


Peter

 

[philipoakley]

Bizcoz,
Unfortunately you don't have what you think you have.
As written, what you have is two range variables - these are implied for loops.

You can assign NaN (Not a Number) to a result to indicate undefined.

I presume you are doing 'numeric' calculations rather than fancy formula manipulation (symbols).

f1(a):=a
f2(b):=b
[f1, f2 not really needed]

F3(a,b):=if(a+b>10,NaN,a+b)

Philip
Stick a work sheet on

http://collab.mathsoft.com/~Mathcad2000

for more replies

 

[Briscoz]

Thanks,
It is fact, that I didnt need funcitons f1 and f2 ,
but NaN didn´t help me

When I used NaN, then 3d graph diseppeared.

I create attachment to show you my problem with zero.

 

[pstuckey]

One possibility would be to set the "undefined" value to something out of range, then manually set your z axis so this range is not shown. For instance in your plot on the upper left: set the undefined value to be -1 (rather than 0), then left click the graph, select properties, uncheck auto scale z axis, then set the z axis limits to 0 and 10.

Peter

 

[philipoakley]

If you save as V11 format (.mcd) then more folk can read it.

There are still a large community who are sticking at V11 until V14/15 becomes more stable and efficient.

V14 is good for pro/e integration but still has a couple of rough edges for those using symbolics [has new MuPad engine].

Philip

 

[Briscoz]

When I used NaN, then symbol below the graf become red.
I tried manually set the range but this was without effect

I saved it into a test.mcd W11 file

 

[philipoakley]

I'm getting a set of plots in V11.

What am I looking for that isn't working?