Store a fixed value in the variable only once - matlab

I have a variable in my code called p_fix. It is necessary to save the value of this variable when PE>p. But the way I did it, every time PE>p is respected, the value of this variable is changed, how can I save its value only once when PE>p and never change the value of this variable (p_fix) again?
for n = 1:size(t,1)
if n>=4
X = [Ia(n-1,1) Ia(n-2,1) ; Ia(n-2,1) Ia(n-3,1)];
future = [Ia(n,1) ; Ia(n-1,1)];
C = X\future;
Ia_future(n,1) = C(1,1)*Ia(n,1)+C(2,1)*Ia(n-1,1);
PE(n,1)=Ia(n,1)+Ia_future(n,1);
p(n,1)=(1+0.2)*max(PE(n-1,1));
if PE(n-1,1)>p(n,1)
p_fix = p(n,1);
end
end
end

You can either:
Before the loop, initialize p_fix to an empty array, and only set it if it’s empty:
if isempty(p_fix) && PE(n-1,1)>p(n,1)
p_fix = p(n,1);
end
Or use a second Boolean variable, for example done, that keeps track of whether you’ve set your other variable or not. Initialize it to false before the loop, then:
if ~done && PE(n-1,1)>p(n,1)
p_fix = p(n,1);
done = true;
end

Related

The PERSISTENT declaration must precede any use of the variable

While working on my matlab homework, I came across a very strange bug. Here's my code:
function [z,times] = Divide(x,y)
persistent times;
if (y == 0)
if (isempty(times))
times = 1;
else
times = times + 1;
end
end
z = x/y;
end
When run, this gives me the error:
Error: File: Divide.m Line: 3 Column: 16
The PERSISTENT declaration must precede any use of the variable times.
This is strange, because it is telling me that I need to declare the variable as persistent before I declare it as persistent (!?). I have no idea what I'm doing wrong here, so if there's some strange workaround that I should be using, please tell me.
The error message means : you've used the 'times' before you declare it as persistent variable. As you used 'times' in return variables.
One of the solution might be keep two different variables for 'times', one for persistent, and another one for return variable.
Paste my change here for your reference. Good luck!
function [z,times] = Divide(x,y)
persistent p_times;
if (y == 0)
if (isempty(p_times))
p_times = 1;
else
p_times = p_times + 1;
end
end
times = p_times;
z = x/y;
end

how to pass cellrange to a user defined macro paramenter

i would like to work with cellranges within my macro.
Function SumIfColor(SumRange)
Dim oRange as object
Dim oSheet as object
' Get Access to the Active Spreadsheet
oSheet = ThisComponent.CurrentController.ActiveSheet
' Get access to the Range listed in Sum Range
oRange = oSheet.getCellRangeByName(SumRange).RangeAddress
End Function
The question is how can I call this function with real cellRange object instead of String. Because getCellRangeByName works only with String variable.
Because when I call the function like this
sumifcolor(B1:B3)
I got the following error:
"Object variable not set"
I read some hint here but it did not helped me.
It is not possible to pass an actual CellRange object. One solution is to pass the row and column number, similar to the second part of #Axel Richter's answer in the link:
Function SumIfColor(lcol1, lrow1, lcol2, lrow2)
sum = 0
oCellRange = ThisComponent.CurrentController.ActiveSheet.getCellRangeByPosition(_
lcol1-1,lrow1-1,lcol2-1,lrow2-1)
For lCol = 0 To oCellRange.Columns.Count -1
For lRow = 0 To oCellRange.Rows.Count -1
oCell = oCellRange.getCellByPosition(lCol, lRow)
If oCell.CellBackColor > -1 Then
sum = sum + oCell.Value
End If
Next
Next
SumIfColor = sum
End Function
To call it:
=SUMIFCOLOR(COLUMN(B1:B3),ROW(B1),COLUMN(B3),ROW(B3))
The sum will be recalculated whenever a value in the range B1:B3 is changed, because of COLUMN(B1:B3). However, apparently changing only the color of a cell does not cause it to be recalculated.

TestComplete/JScript- Using a variable in an object path

I am using TestComplete with JScript testing a webpage that has elements that I declare as a variable to make it easier to test the element later. They all have a path like:
var check1 = Window.Panel(1).Panel(2).Panel(0).Panel(0).Panel(0).Panel(0).Panel(1).Panel(0).Label(0).Checkbox(0)
The elements are dynamic, so there is no telling how many there are when the test is run. I was hoping there was some way to loop through and declare the elements, but it would involve declaring the element like this:
var check1 = Window.Panel(1).Panel(2).Panel(0).Panel(0).Panel(0).Panel(0).Panel(1).Panel(0).Label(x).Checkbox(0)
where x is the counter variable. The problem is that TestComplete sees this as a literal path and does not recognize x as a variable.
Is there any way to do this with TestComplete using JScript? Or convert a string to an object? I think I can work with that, too.
My guess is that since you store the reference in variable check1, the variable x is updated but the x in variable check1 still holds it's original value (1).
Workaround
Keep the first part of the path static in the variable, then update x and assign it to the label.
var path = Window.Panel(1).Panel(2).Panel(0).Panel(0).Panel(0).Panel(0).Panel(1).Panel(0);
// path to the Checkbox
path.Label(x).Checkbox(0);
// or if you want to loop over it
for (var x = 0, len = 8; i < len; x += 1) {
if (path.Label(x).Checkbox(0).value === 'something') {
console.log('hooray!');
}
}

Variable input to MATLAB function resets involuntarily inside while loop. How can I prevent it?

I have written a function which takes in an integer (int8) as one of the inputs (called iscool). The function runs a while loop and I insert an if-check inside it to break out of the loop. The if-check checks the value of the iscool variable as well and sets the value of imarch to 0 to get out of loop. So basically, the code is something like this.
% Code_snippet
while (imarch == 1)
<some procedures not modifying iscool>
if ((iscool == 0) && (<other condition 1>) && (<other condition 2>))
imarch = 0;
elseif ((iscool == 1) && (<other condition 3>) && (<other condition 4>))
imarch = 0;
end
disp (strcat('Cooling index is: ',num2str(iscool)));
end
The output of the disp command in the first while-loop execution is 0 (which is the input), but it changes to 1 in the subsequent iteration and stays so after that. I have tried removing the if-elseif-end check and the value of iscool stays intact in that case, but I need to have the check in order to be able to get out of the loop. Any sort of help, particularly an insight into why the value might be changing would be great help. Thanks.

Passing a variable out of local functions

I'm having some trouble with local functions within my code so I've pasted a simple example below:
function [avg,testvar] = test(x) %Warning
n = length(x);
avg = mymean(x,n);
end
function [a,testvar] = mymean(v,n)
a = sum(v)/n;
testvar=123;
end
One can probably see what I'm attempting; to pass testvar out of the local functions. However Matlab returns the warning:
"The function return value 'testvar' might be unset"
with respect to the line I've commented "%Warning".
What's the best way of getting around this?
You need to specify the value of the second output of test(). Otherwise how can MATLAB know what its value is supposed to be? It doesn't know the second output of mymean() should be routed to the second output of test(). Perhaps this will solve your problem.
function [avg,testvar] = test(x) %Warning
n = length(x);
[avg, testvar] = mymean(x,n);
end
function [a,testvar] = mymean(v,n)
a = sum(v)/n;
testvar=123;
end
The variables between brackets after function are the output variables.
In your first function, you did not assign any value to testvar hence the warning. If you add testvar = 123; in the first function, the warning goes away. Or you can remove testvar from the output variables, leaving:
function avg = test(x)