I'm using pyqt and have two QDoubleSpinBoxes which I use to define intervals. Typically those intervals are integer, e.g. degree Celsius. Depending on the use case I switch the range, stepsize, unit, etc. One case involves voltage and needs to be decimal, so I always use QDoubleSpinBox but reduce decimals and stepsize to correspond to integers. Here is a snippet for the voltage case:
self.to_spin.setDecimals(2)
self.from_spin.setDecimals(2)
self.to_spin.setSuffix(" V")
self.from_spin.setSuffix(" V")
self.to_spin.setSingleStep(0.1)
self.from_spin.setSingleStep(0.1)
self.to_spin.setRange(0.0,40.0)
self.from_spin.setRange(0.0,40.0)
if set_defaults:
self.from_spin.setValue(2.0)
self.to_spin.setValue(18.0)
The Problem is, that even in the Scenario above the values entered are always corrected to the nearest integer.
I use QDoubleSpinBoxes in a different place but without varying the intervals, etc. and there it is working as it should be.
Any suggestions? The validator should be okay because it's a DoubleBox, right?
Any help is appreciated - thanks in advance,
Ben
In the meantime, I believe, I found out what the problem were: if one of the values used to define range, stepsize and so on is integer, the entered value jumps to integer as well. Anyway, now it works.
Related
This uppaal model showing in the image is part of a top system.
It's used to check the condition var==1 hold for at least 10 time units. The range of the integer variable var is [0, 20000].
I use query E<>condition.hold to get the trace, but can't get result within minutes. If I change the range of var to [0, 1000], uppaal return result within seconds.
The question is:
Do I use uppaal in a right way?
Is uppaal suitable for this kind of model-checking? or any other options?
Thanks for any help
Due to the problem domain that we deal with, the model need to support integer and float data type. And now I understood that Uppaal treat clock as symbolic representation but other variables as concrete value, so maybe it's not possible to meet our requirement. And I am going to try nuxmv, which seems OK because SMT solver is used. I'm not sure whether nuxmv is suitable for timed automata modeling. Have a try.
I am having some strange problems with excel's solver. Basically what I am trying to do is curve fit my data. I have two different lines, one is my calibration line and the other is the derived line that I am attempting to match up to the calibration line. My line depends on 19 different variable parameters (Perhaps this is too many? I have tried fewer without result) and I am using solver to adjust these parameters to make the two lines as close as possible.
For Example:
The QP column contains the variables I would like changed, changing these will draw me closer or further from the calibration curve. Each subsequent value of QP must be greater than the first.
Col=B Col=C
Power .QP_'
1 ..... 57000
2 ..... 65000
3 ..... 70000
4 ..... 80000
5 ..... 80000
Therefore my excel solver parameters look like this: C1:C19>=0,C1:C19<=100000 and C2>=C1, C3>=C2,C4>=C3... I have also tried making another column of the differences between each value and then saying that these must be diff>=0.
To compare this with my calibration curve I have taken the calibration curve data and subtracted my data derived from QP and then squared that to create my sum of the squares error. For example:
(Calibration-DerivedQP)^2=SS(x) <- where x represents the row number
Sum(SS(x))=SSE
SSE is what I have set solver to minimize. And upon changing QP everything automatically updates. There are no if statements being used and no pivot tables are used.
If I remove the parameters similar to C2>=C1 everything works perfectly, except the derived values are not feasible. But when the solver is run with these parameters, nothing gets changed and no matter which guesses I used as starting values ( so that I can ensure I haven't guessed a local minimum), the solver cannot improve upon my solution. This has led me to believe that something in my parameters is being broken, since I can very easily improve on my solution by guess and check. The rest of solvers settings are at the defaults, and the evolutionary method is used since my curve isn't smooth (I don't think) I had this working in the past and now something seems to be broken. Any ideas are appreciated! Thank you so much! Sorry if I am missing any critical information. I am also familiar with matlab and R if there are better methods in those languages.
I found the solution to my problem. I don't know if this will be helpful to anyone else since my problem vague and pretty specific to me. That being said, my problem was in the constraints. I changed some data on my excel sheet to allow for fewer constraints. An example might look like this:
Guess..........Squared......Added..................Q
-12..............(-12)^2....... 0
-16..............(-16)^2.......=(-16)^2+0.............256
+7.................(7)^2..........=(7)^2+(-16)^2+0....305
Now I allow solver to guess any number subject to minimal constraints.
Essentially, what is happening now, is the excel sheet allows for any guess that solver makes to work. By squaring the numbers it give me positive values, and the added column ensures that each successive value is equal to or greater than the first. This means there are very few constraints. I also changed the solver option from evolutionary to GRG Nonlinear.
Tips for getting solver to work:
Try and use the spreadsheet to set constraints (other than bounds, bounds seem to be good) wherever possible, the more constraints that I set in solver, the less likely my solution was to work.
Hope that helps, sorry if I have provided any incorrect information.
I need to output lots of (>20 million) float values to a text file from a Fortran 77 program. I'd like to keep the output file as small as possible. Therefore I would like to output the floats in a compact way, without resorting to binary.
I know the precision I need (usually two digits right of the decimal point), so in C I would use printf("%.2f %.2f", val1, val2); Is something like this possible in Fortran 77? All I found was that I have to set the field width explicitly (like in format (f8.2,x,f8.2)). This wastes lots of space, when I don't know the range of the output numbers beforehand.
If it is not possible in Fortran 77, do newer Fortran standards offer a way to do this?
The Fortran 2008 standard allows an edit descriptor such as f0.2 in response to which the output is the smallest possible field width which writes the whole part of the number followed by a decimal point and two fractional digits. I think that this has been part of the language standard since Fortran 90, possibly longer.
If you have a number, X, then INT(LOG10(X))+1 is the size of the integer part of your number (number of digits of the integer part). So, you just have to make some custom FORMAT labels for each of the values you want to print.
It is not very elegant, but I think it will help you achieve what you want.
I know this might come across as pedantic and unhelpful, but hear me out. It sounds like you are doing bad science. If your instrument is spitting out numbers from 1000.00 to 0.01, then your instrument is probably only accurate to one part in a hundred. So the number 9894.36 ought to be rounded to 9900 (no decimal point). All the other digits are not significant. Why is that relevant and helpful? Because you are wasting storage space if you are storing 9894.36. So, the answer is to use the g edit descriptor, which outputs in scientific notation. Then all of your numbers will take up the same space.
I am monitoring an application using Zabbix and have defined a custom item which returns a string value. Since my item's values are actually checksums, they will only contain the characters [0-9a-f]. Two mirror copies of my application are running on two servers for the sake of redundancy. I would like to create a trigger which would take the item values from both machines and fire if they are not the same.
For a moment, let's forget about the moment when values change (it's not an atomic operation, so the system may see inconsistent state, which is not a real error, for a short time), since I could work around it by looking at several previous values.
The crux is: how to write a Zabbix trigger expression which could compare for equality the string values of two items (the same item on two mirror hosts, actually)?
Both according to the fine manual and as I confirmed in praxis, the standard operators = and # only work on numeric values, so I can't just write the natural {host1:myitem[param].last(0)} # {host2:myitem[param].last(0)}. Functions such as change() or diff() can only compare values of the same item at different points in time. Functions such as regexp() can only compare the item's value with a constant string/regular expression, not with another item's value. This is very limiting.
I could move the comparison logic into the script which my custom item executes, but it's a bit messy and not elegant, so if at all possible, I would prefer to have this logic inside my Zabbix trigger.
Perhaps despite the limitations listed above, someone can come up with a workaround?
Workaround:
{host1:myitem[param].change(0)} # {host2:myitem[param].change(0)}
When only one of the servers sees a modification since the previously received value, an event is triggered.
From the Zabbix Manual,
change (float, int, str, text, log)
Returns difference between last and previous values.
For strings:
0 - values are equal
1 - values differ
I believe, and am struggling with this EXACT situation to this myself, that the correct way to do this is via calculated items.
You want to create a new ITEM, not trigger (yet!), that performs a calculated comparison on multiple item values (Strings Difference, Numbers within range, etc).
Once you have that item, have the calculation give you a value you can trigger off of. You can use ANY trigger functions in your calculation along with arrhythmic operations.
Now to the issue (which I've submitted a feature request for because this is extremely limiting), most trigger expressions evaluate to a number or a 0/1 bool.
I think I have a solution for my problem, which is that I am tracking a version number from a webpage: e.g. v2.0.1, I believe I can use string connotation and regex in calculated items in order to convert my string values into multiple number values. As these would be a breeze to compare.
But again, this is convoluted and painful.
If you want my advice, have yourself or a dev look at the code for trigger expressions and see if you can submit a patch add one trigger function for simple string comparison. (Difference, Length, Possible conversion to numerical values (using binary and/or hex combinations) etc.)
I'm trying to work on a patch myself, but I don't have time as I have so much monitoring to implement and while zabbix is powerful, it's got several huge flaws. I still believe it's the best monitoring system out there.
Simple answer: Create a UserParameter until someone writes a patch.
You could change your items to return numbers instead of strings. Because your items are checksums that are using only [0-9a-f] characters, they are numbers written in hexadecimal. So you would need to convert the checksum to decimal number.
Because the checksum is a big number, you would need to limit the hexadecimal number to 8 characters for Numeric (unsigned) type before conversion. Or if you would want higher precision, you could use float (but that would be more work):
Numeric (unsigned) - 64bit unsigned integer
Numeric (float) - floating point number
Negative values can be stored.
Allowed range (for MySQL): -999999999999.9999 to 999999999999.9999 (double(16,4)).
I wish Zabbix would have .hashedUnsigned() function that would compute hash of a string and return it as a number. Such a function should be easy to write.
We have an alpha numeric string (up to 32 characters) and we want to transform it to an integer (bigint). Now we're looking for an algorithm to do that. Collision isn't bad (therefor we use an bigint to prevent this a little bit), important thing is, that the calculated integers are constantly distributed over bigint range and the calculated integer is always the same for a given string.
This page has a few. You'll need to port to 64bit, but that should be trivial. A C# port of SBDM hash is here. Another page of hash functions here
Most programming languages come with a built-in construct or a standard library call to do this. Without knowing the language, I don't think anyone can help you.
Yes, a "hash" should be the right description for my problem. I know, that there is CRC32, but it only provides an 32-bit int (in PHP) and this 32-bit integers are at least 10 characters long, so a huge range of integer number is unused!?
Mostly, we have a short string like "PX38IEK" or an 36 character UUID like "24868d36-a150-11df-8882-d8d385ffc39c", so the strings are arbitrary, yes.
It doesn't has to be reversible (so collisions aren't bad). It also doesn't matter what int a string is converted to, my only wish is, that the full bigint range is used as best as possible.