Can't find sat() function

Hi, I want to use sat function (which is a saturation function) but I not sure which toolbox contains this function. Can anyone help? :) Urgent question!!!

[John D'Errico]

https://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

Luckily, I had some free time, and your problem was easy to solve. But remember that we don't really care that your problem is urgent, and that every other person asking a question on Answers has just as much a right to hope for a timely answer to their questions as do you.

Finally, I would comment that the answer I did post was something you could have trivially found in far less time than it took you to write the question and for me to give you an answer.

[Jennie Leong]

Sorry about that and thanks for answering to my question :)

Answer 1

[John D'Errico]

which sat -all

'sat' not found.

sat.m is not found in any MathWorks provided toolbox.

You may need to ask your instructor, since they may have written this code. Another possibility is that function may be found on the file exchange. So I looked there. (You could have done as easily!)

When I did so, after a looking at dozens of tools, I found this:

https://www.mathworks.com/matlabcentral/fileexchange/2165-feedback-control-of-dynamic-systems-3e?s_tid=srchtitle

which does have a function named sat.m

function y=sat(x);
% sat is the saturation function with unit limits and unit slope.
if x>1
    y=1;
elseif x<-1 
    y=-1;
else 
    y=x;
end

which does something with a saturation. Is that what you want? God only knows. :) well, you may know. Anyway, that function sat is actually pretty simple.

[Walter Roberson]

function y = sat(x)
  %vectorized version
  y = max(-1, min(1, x));
end

[Life is Wonderful]

This is Buggy suggestion !!

x = -2147483647

x = -2.1475e+09

y = max(-1, min(1, x))

y = -1

input-value (Decimal): -2147483647
input-value (Decimal): 80000001
input-value (Decimal): 10000000000000000000000000000001
Reduced and saturated value (Decimal): 2147483647
Reduced and saturated value (Hex): 7FFFFFFF
Reduced and saturated value (Binary): 01111111111111111111111111111111

[Steven Lord]

No, this suggestion is working as expected for the input you provided.

I think you're assuming that 1) x is stored in an integer type [it's not, x is a double array] and 2) MATLAB uses wrapping arithmetic for integers [it doesn't, it saturates.]

x = -2147483647

x = -2.1475e+09

class(x) % double not one of the integer types

ans = 'double'

minval = intmin('int32') % This is stored as an int32

minval = int32 -2147483648

maxval = intmax('int32')

maxval = int32 2147483647

z = minval-1 % equal to minval not maxval

z = int32 -2147483648

w = maxval+1 % equal to maxval not minval

w = int32 2147483647