I ran into a strange statement when working on a COBOL program from $WORK.
We have a paragraph that is opening a cursor (from DB2), and the looping over it until it hits an EOT (in pseudo code):
... working storage ...
01 I PIC S9(9) COMP VALUE ZEROS.
01 WS-SUB PIC S9(4) COMP VALUE 0.
... code area ...
PARA-ONE.
PERFORM OPEN-CURSOR
PERFORM FETCH-CURSOR
PERFORM VARYING I FROM 1 BY 1 UNTIL SQLCODE = DB2EOT
do stuff here...
END-PERFORM
COMPUTE WS-SUB = I + 0
PERFORM CLOSE-CURSOR
... do another loop using WS-SUB ...
I'm wondering why that COMPUTE WS-SUB = I + 0 line is there. My understanding is that I will always at least be 1, because of the perform block above it (i.e., even if there is an EOT to start with, I will be set to one on that initial iteration).
Is that COMPUTE line even needed? Is it doing some implicit casting that I'm not aware of? Why would it be there? Why wouldn't you just MOVE I TO WS-SUB?
Call it stupid, but with some compilers (with the correct options in effect), given
01 SIGNED-NUMBER PIC S99 COMP-5 VALUE -1.
01 UNSIGNED-NUMBER PIC 99 COMP-5.
...
MOVE SIGNED-NUMBER TO UNSIGNED-NUMBER
DISPLAY UNSIGNED-NUMBER
results in: 255. But...
COMPUTE UNSIGNED-NUMBER = SIGNED-NUMBER + ZERO
results in: 1 (unsigned)
So to answer your question, this could be classified as a technique used cast signed numbers into unsigned numbers. However, in the code example you gave it makes no sense at all.
Note that the definition of "I" was (likely) coded by one programmer and of WS-SUB by another (naming is different, VALUE clause is different for same purpose).
Programmer 2 looks like "old school": PIC S9(4), signed and taking up all the digits which "fit" in a half-word. The S9(9) is probably "far over the top" as per range of possible values, but such things concern Programmer 1 not at all.
Probably Programmer 2 had concerns about using an S9(9) COMP for something requiring (perhaps many) fewer than 9999 "things". "I'll be 'efficient' without changing the existing code". It seems to me unlikely that the field was ever defined as unsigned.
A COMP/COMP-4 with nine digits does have a performance penalty when used for calculations. Try "ADD 1" to a 9(9) and a 9(8) and a 9(10) and compare the generated code. If you can have nine digits, define with 9(10), otherwise 9(8), if you need a fullword.
Programmer 2 knows something of this.
The COMPUTE with + 0 is probably deliberate. Why did Programmer 2 use the COMPUTE like that (the original question)?
Now it is going to get complicated.
There are two "types" of "binary" fields on the Mainframe: those which will contain values limited by the PICture clause (USAGE BINARY, COMP and COMP-4); those which contain values limited by the field size (USAGE COMP-5).
With BINARY/COMP/COMP-4, the size of the field is determined from the PICture, and so are the values that can be held. PIC 9(4) is a halfword, with a maxiumum value of 9999. PIC S9(4) a halfword with values -9999 through +9999.
With COMP-5 (Native Binary), the PICture just determines the size of the field, all the bits of the field are relevant for the value of the field. PIC 9(1) to 9(4) define halfwords, pic 9(5) to 9(9) define fullwords, and 9(10) to 9(18) define doublewords. PIC 9(1) can hold a maximum of 65535, S9(1) -32,768 through +32,767.
All well and good. Then there is compiler option TRUNC. This has three options. STD, the default, BIN and OPT.
BIN can be considered to have the most far-reaching affect. BIN makes BINARY/COMP/COMP-4 behave like COMP-5. Everything becomes, in effect, COMP-5. PICtures for binary fields are ignored, except in determining the size of the field (and, curiously, with ON SIZE ERROR, which "errors" when the maxima according to the PICture are exceeded). Native Binary, in IBM Enterprise Cobol, generates, in the main, though not exclusively, the "slowest" code. Truncation is to field size (halfword, fullword, doubleword).
STD, the default, is "standard" truncation. This truncates to "PICture". It is therefore a "decimal" truncation.
OPT is for "performance". With OPT, the compiler truncates in whatever way is the most "performant" for a particular "code sequence". This can mean intermediate values and final values may have "bits set" which are "outside of the range" of the PICture. However, when used as a source, a binary field will always only reflect the value specified by the PICture, even if there are "excess" bits set.
It is important when using OPT that all binary fields "conform to PICture" meaning that code must never rely on bits which are set outside the PICture definition.
Note: Even though OPT has been used, the OPTimizer (OPT(STD) or OPT(FULL)) can still provide further optimisations.
This is all well and good.
However, a "pickle" can readily ensue if you "mix" TRUNC options, or if the binary definition in a CALLing program is not the same as in the CALLed program. The "mix" can occur if modules within the same run-unit are compiled with different TRUNC options, or if a binary field on a file is written with one TRUNC option and later read with another.
Now, I suspect Programmer 2 encountered something like this: Either, with TRUNC(OPT) they noticed "excess bits" in a field and thought there was a need to deal with them, or, through the "mix" of options in a run-unit or "across file usage" they noticed "excess bits" where there would be a need to do something about it (which was to "remove the mix").
Programmer 2 developed the COMPUTE A = B + 0 to "deal" with a particular problem (perceived or actual) and then applied it generally to their work.
This is a "guess", or, better, a "rationalisation" which works with the known information.
It is a "fake" fix. There was either no problem (the normal way that TRUNC(OPT) works) or the correct resolution was "normalisation" of the TRUNC option across modules/file use.
I do not want loads of people now rushing off and putting COMPUTE A = B + 0 in their code. For a start, they don't know why they are doing it. For a continuation it is the wrong thing to do.
Of course, do not just remove the "+ 0" from any of these that you find. If there is a "mix" of TRUNCs, a program may stop "working".
There is one situation in which I have used "ADD ZERO" for a BINARY/COMP/COMP-4. This is in a "Mickey Mouse" program, a program with no purpose but to try something out. Here I've used it as a method to "trick" the optimizer, as otherwise the optimizer could see unchanging values so would generate code to use literal results as all values were known at compile time. (A perhaps "neater" and more flexible way to do this which I picked up from PhilinOxford, is to use ACCEPT for the field). This is not the case, for certain, with the code in question.
I wonder if a testing version of the sources ever had
COMPUTE WS-SUB = I + 0
ON SIZE ERROR
DISPLAY "WS-SUB overflow"
STOP RUN
END-COMPUTE
with the range test discarded when the developer was satisfied and cleaning up? MOVE doesn't allow declarative SIZE statements. That's as much of a reason as I could see. Or perhaps developer habit of using COMPUTE to move, as a subtle reminder to question the need for defensive code at every step? And perhaps not knowing, as Joe pointed out, the SIZE clause would be just as effective without the + 0? Or a maintainer struggled with off by one errors and there was a corrective change from 1 to 0 after testing?
Related
So I have created a huge screen that essentially just shows the robot status for every robot in this factory (individually)… At the very end of the project, they decided they want one object on the screen that blinks if any of the 300 robots fault. I am trying to think of a way to make this work. Maybe a global script of some kind? Problem is, I do not do much scripting in Cimplicity, so any help is appreciated.
All the points that are currently used on this screen (to indicate a fault) have very similar names… as in, the beginning is the same… so I was thinking of a script that could maybe recognize if a bit is high based on PART of it's string name characteristic. The end will change a little each time, but I am sure there is a way to only look for part of a string and negate the rest. If the end has to be hard coded, that's fine.
You can use a Python script in Cimplicity.
I will not go into detail on the use of python in Cimplicity, which is well described in the documentation indicated above.
Here's an example of what can be done... note that I don't have a way to test it and, of course, this will work if the name of your robots in the declaration follows the format Robot_1, Robot_2, Robot_3 ... Robot_10 ... Robot_300 and it also depends on the Name and the Type of the fault variable... as you didn't define it, I imagine it can be an integer, with ZERO indicating no error. But if you use something other than that, you can easily change it.
import cimplicity
(...)
OneRobotWithFault = False
# Here you get the values and check for fault
for i in range(0, 300):
pointName = f'MyFactory.Robot_{i}.FaultCode'
robotFaultCode = cimplicity.point_get(pointName)
if robotFaultCode > 0:
OneRobotWithFault = True
break
# Set the status to the variable "WeHaveRobotWithFault"
cimplicity.point_set("WeHaveRobotWithFault", OneRobotWithFault)
I am using clingo to solve a homework problem and stumbled upon something I can't explain:
normalized(0,0).
normalized(A,1) :-
A != 0.
normalized(10).
In my opinion, normalized should be 0 when the first parameter is 0 or 1 in every other case.
Running clingo on that, however, produces the following:
test.pl:2:1-3:12: error: unsafe variables in:
normalized(A,1):-[#inc_base];A!=0.
test.pl:2:12-13: note: 'A' is unsafe
Why is A unsafe here?
According to Programming with CLINGO
Some error messages say that the program
has “unsafe variables.” Such a message usually indicates that the head of one of
the rules includes a variable that does not occur in its body; stable models of such
programs may be infinite.
But in this example A is present in the body.
Will clingo produce an infinite set consisting of answers for all numbers here?
I tried adding number(_) around the first parameter and pattern matching on it to avoid this situation but with the same result:
normalized(number(0),0).
normalized(A,1) :-
A=number(B),
B != 0.
normalized(number(10)).
How would I write normalized properly?
With "variables occuring in the body" actually means in a positive literal in the body. I can recommend the official guide: https://github.com/potassco/guide/releases/
The second thing, ASP is not prolog. Your rules get grounded, i.e. each first order variable is replaced with its domain. In your case A has no domain.
What would be the expected outcome of your program ?
normalized(12351,1).
normalized(my_mom,1).
would all be valid replacements for A so you create an infinite program. This is why 'A' has to be bounded by a domain. For example:
dom(a). dom(b). dom(c). dom(100).
normalized(0,0).
normalized(A,1) :- dom(A).
would produce
normalize(0,0).
normalize(a,1).
normalize(b,1).
normalize(c,1).
normalize(100,1).
Also note that there is no such thing as number/1. ASP is a typefree language.
Also,
normalized(10).
is a different predicate with only one parameter, I do not know how this will fit in your program.
Maybe your are looking for something like this:
dom(1..100).
normalize(0,0).
normalize(X,1) :- dom(X).
foo(43).
bar(Y) :- normalize(X,Y), foo(X).
I am using deep speech for speech to text. Up to 0.8.1, when I ran transcriptions like:
byte_encoding = subprocess.check_output(
"deepspeech --model deepspeech-0.8.1-models.pbmm --scorer deepspeech-0.8.1-models.scorer --audio audio/2830-3980-0043.wav", shell=True)
transcription = byte_encoding.decode("utf-8").rstrip("\n")
I would get back results that were pretty good. But since 0.8.2, where the scorer argument was removed, my results are just rife with misspellings that make me think I am now getting a character level model where I used to get a word-level model. The errors are in a direction that looks like the model isn't correctly specified somehow.
Now I when I call:
byte_encoding = subprocess.check_output(
['deepspeech', '--model', 'deepspeech-0.8.2-models.pbmm', '--audio', myfile])
transcription = byte_encoding.decode("utf-8").rstrip("\n")
I now see errors like
endless -> "endules"
service -> "servic"
legacy -> "legaci"
earning -> "erting"
before -> "befir"
I'm not 100% that it is related to removing the scorer from the API, but it is one thing I see changing between releases, and the documentation suggested accuracy improvements in particular.
Short: The scorer matches letter output from the audio to actual words. You shouldn't leave it out.
Long: If you leave out the scorer argument, you won't be able to detect real world sentences as it matches the output from the acoustic model to words and word combinations present in the textual language model that is part of the scorer. And bear in mind that each scorer has specific lm_alpha and lm_beta values that make the search even more accurate.
The 0.8.2 version should be able to take the scorer argument. Otherwise update to 0.9.0, which has it as well. Maybe your environment is changed in a way. I would start in a new dir and venv.
Assuming you are using Python, you could add this to your code:
ds.enableExternalScorer(args.scorer)
ds.setScorerAlphaBeta(args.lm_alpha, args.lm_beta)
And check the example script.
I'm new to ASP & Clingo and I need to work on a project for school. I thought about some basic music generator.
For now, I need to generate notes (I'm sticking with C major for now). I also want to generate them randomly and I don't know how to do that. How can I make the following code generate a random sequence of notes (duplicates too)?
note(c;d;e;f;g;a;b).
20 { play(X) : note(X)} 30.
#show play/1.
So far, the code won't allow for more than 7 as the upper bound, because it won't show duplicate notes.
Current output: play(b) play(g) play(e) play(c)
Wanted output: play(d) play(g) play(f) ...[20-30 randomly generated notes]
I want to be able to add constraints later (such as this note should not be followed by that note, and so on). I appreciate any tips since I know so little about this.
An answer set is a set. The atoms have no order and duplicates are not possible because it is a set.
You want to guess one note for each beat.
beat(1..8).
1 { play(N,B) : note(N) } 1 :- beat(B).
Among many distressing graphics changes to r2014b, the Plot Browser now only displays a certain number of lines per plot (looks like the limit is 50). Any number of plots above this limit are not displayed in the Plot Browser - it just says "and 78 more..."
Is there anyway to remove the limit? I want to see all my lines in the plot browser.
Unfortunately the answer is currenty:
No you cannot remove this limit
This was already reported to mathworks a while ago, and here is the reply:
I am writing in reference to your Technical Support Case #01143663
regarding 'plot browser with "and xxxx more...." indication'.
Really interesting question (and even a bit surprising). Basically
this limitation has been introduced with MATLAB 2014b!
Our developers are aware of that, and they are working to solve it. An
enhancement/bug request has been already submitted, and I am going to
add this case to the list. However, I cannot guarantee you a release
date.
If you think this limitation is crucial for your work, I would
strongly suggest you to contact your account manager, which will have
a bit more influence on the developers than a simple engineer :).
Of course, if there is anything else I can do for you, please let me
know
So it seems that you will have to deal with this limitation if you keep using 2014b.
This was also an issue for me; in particular I wanted to see the DisplayName property of the graphics object in the list. I used a workaround where I created a callback function, so that when clicking on a data point, the DisplayName would be shown. This can be helpful if you have a plot of many lines and want to see the DisplayName of a particular one. You would first need to set the DisplayName property of the graphics objects for this to work, as it's empty by default. You could also use this to show other properties, such as Color or LineStyle, that are shown in the plot browser:
%Based on
%http://www.mathworks.com/help/matlab/ref/datacursormode.html
%'fig_h' is the figure handle
dcm_obj = datacursormode(fig_h);
set(dcm_obj,'UpdateFcn',#myupdatefcn)
And then include this function as a separate file on the Matlab path, or paste into the function you're currently writing, and include an extra 'end' at the end of that function:
function name = myupdatefcn(empt,event_obj)
% Customizes text of data tips
tar = get(event_obj,'Target');
name = get(tar,'DisplayName');
end