Absolute Value

[jenny29]

I am having an issue with finding the max value of positive and negative values.  I want it to always pick the highest integer but to have it's sign remain the same.  

For instance,

x=10, y=15, z=-20 are my numbers calculated that 

t:=550*[max(x,y,z)] -p is depended on.

 if I do r:= max(x,y,z) it will state that r=15 when I need it to pick the worse case for an equation it will be integrated in later on. 

if I do r:= max(IxI,IyI,IzI) it will state r=20 but not -20 cause of the absolute value.

Is there a different approach I can do where I wouldn't have to use solve for t for each single case and pick the max absolute value of all three?

[terryhendicott]

max(|x|,|y|,|z|)=max(x,y,z)

This is fallible but works most of the time

if test is true you have a positive number
if test is false you have a negative number

[LucMeekes · Accepted solution]

Define your own function maxabs:

Success!
Luc

[AlvaroDíaz]

Hi Luc. I guess that your solution is correct, just a margin note: If x = max(A) then -x = min(-A). 

Best regards.

Alvaro.

[Werner_E]

Here are my 2 cents

 

[jenny29]

When I do that, it tells me that "these values must all be of one type."  

I am not sure what that means.

[jenny29]

Actually I was able to make it work with your method, Luc. thank you.  My issue was that I was mixing {2,1} variables with {1,1} when what I needed to do first is find the maxabs of the {2,1} and then combine them all in one matrix to find the total maxabs of (B).  It's a bit longer the steps but it gives the correct solution.