I am new to sage and have got a code (link to code) which should run.
I am still getting an error message in the decoding part. The error trace looks like this:
in decode(y)
--> sigma[i+1+1] = sigma[i+1]*(z)\
-(delta[i+1]/delta[mu+1])*z^(i-mu)*sigma[mu+1]*(z);
in sage.structure.element.Element.__mul__
if BOTH_ARE_ELEMNT(cl):
--> return coercion_model.bin_op(left, right, mul)
in sage.structure.coerce.CoercionModel_cache_maps.bin_op
--> action = self.get_action(xp,yp,op,x,y)
...... some more traces (don't actually know if they are important)
TypeError: positive characteristics not allowed in symbolic computations
Does anybody know if there is something wrong in this code snipped? Due to previous errors, I changed the following to get to where I am at the moment:
.coeffs() changed to .coefficients(sparse=False) due to a warning message.
in the code line sigma[i+1+1] = sigma[i+1](z)\
-(delta[i+1]/delta[mu+1])*z^(i-mu)*sigma[mu+1](z); where the error occurs, i needed to insert * eg. sigma[i+1]*(z)
I would be grateful for any guess what could be wrong!
Your issue is that you are multiplying things not of characteristic zero (like elements related to Phi.<x> = GF(2^m)) with elements of symbolic computation like z which you have explicitly defined as a symbolic variable
Phi.<x> = GF(2^m)
PR = PolynomialRing(Phi,'z')
z = var('z')
Basically, the z you get from PR is not the same one as from var('z'). I recommend naming it something else. You should be able to access this with PR.gen() or maybe PR(z).
I'd be able to be more detailed, but I encourage you next time to paste a fully (non-)working example; trying to slog through a big worksheet is not the easiest thing to track all this down. Finally, good luck, hope Sage ends up being useful for you!
Related
I'm a new user of PARI/GP, and after writing my script, I wanted to make a graph of it. As my function take an integer and return a number, it's closer to a sequence. Actually, I didn't know how to do it, so I read the documentation of PARI/GP, and after that I made some test in order to obtain a graph from a list.
After reading an answer in stackoverflow (Plotting multiple lists in Pari), I wanted to test with the following code:
plothraw([0..200], apply(i->cos(i*3*Pi/200), [0..200]), 0);
But when I do it, it tries to open something on latexit, but then it crash and give me a problem report.
I didn't even know that I had an app named latextit, maybe it was install during the installation of PARI/GP. Anyway, how can I fix this?
PARI/GP definitely doesn't install latexit.
The way hi-res graphics work on the Win32 version of PARI/GP is to write down an Enhanced Metafile (.EMF) in a temp directory and ask the system to
"open" it. When you installed latexit it probably created an association in the registry to let it open .EMF files
i3Pi does not mean what you think, it just creates a new variable with that name. You want i * 3 * Pi instead.
The following constructions both work in my setup
plothraw([0..200], apply(i->cos(i*3*Pi/200), [0..200]), 0);
plothraw([0..200], apply(i->cos(i*3*Pi/200), [0..200]), 1);
(the second one being more readable because a red line is drawn between successive points; I have trouble seeing the few tiny blue dots)
Instead of apply, you can use a direct constructor as in
vector(201, i, cos((i-1) * 3 * Pi / 200))
which of course can be computed more efficiently as
real( powers(exp(3*I*Pi/200), 200) )
(of course, it doesn't matter here, but compare both commands at precision \p10000 or so ...)
When I run a Xcos model containing a scifunc_block_m block like shown below
I get an error message relating to data dimensions inconsistency:
"Data dimensions are inconsistent:"
" Variable size=[1,1]"
"Block output size=[100,1]."
But when I double click in the block in order to see what can I change to make the dimensions correct I get a message in the console saying
Undefined variable: scifunc_block_m
What bugs me is that scifunc_block_m is not the name of any variable, but rather the name of the block itself like can be seen in the official docs.
Of course I double checked that nowhere in my function phase_shifter neither anywhere else I have any variable named like that.
I tried with Scilab 6.1.1 and 6.1.0 believing that it might be a bug from apparently not.
In your phase_shifter.sce file generating the input variable,
the signalIn variable does not comply with the From Workspace block requirements, whose documentation says that the input variable
must be a structure with time and values fields
.time must be a column vector, and in your case
.values must also be a column
So,
t = (0:1/fs:Npp/fs - 1/fs); // time vector
signalIn = A*%e^(%i*w*t);
should be replaced with
t = (0:1/fs:Npp/fs - 1/fs)'; // time column vector
signalIn = struct("time",t, "values",A*%e^(%i*w*t));
This fixes the inconsistent dimensions message.
In addition, i am not able to reproduce your issue about Undefined variable: scifunc_block_m. The parameters interface opens as expected.
You may get this kind of messages if you try to run some xcos parts out of xcos, without beforehand loading xcos-related libraries.
Then, we get an unclear "Output should be of complex type." message on the From workspace block.
By the way, you try to plot some complex values. Please have a look to the MATMAGPHI block before entering MUX: https://help.scilab.org/docs/6.1.1/en_US/MATMAGPHI.html
Using Java 8u222, I've been trying a silly operation and it incurs in an error that I'm not being able to fully understand. The line code:
ZonedDateTime.parse("2011-07-03T02:20:46+06:00[Asia/Qostanay]");
The error:
java.time.format.DateTimeParseException: Text '2011-07-03T02:20:46+06:00[Asia/Qostanay]' could not be parsed, unparsed text found at index 25
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1952)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)
at java.time.ZonedDateTime.parse(ZonedDateTime.java:582)
Using the same date (although the timezone could be incorrect, the intention is just testing here), I changed the square bracket's value and it works, I mean:
ZonedDateTime.parse("2011-07-03T02:20:46+06:00[Europe/Busingen]);
It works as expected, as well as other values such:
ZonedDateTime.parse("2011-07-03T02:20:46+06:00[Asia/Ulan_Bator]")
ZonedDateTime.parse("2011-07-03T02:20:46+06:00[SystemV/CST6CDT]")
I found some similar questions such as the one below, but not precisely the same usage that I'm trying / facing.
Error java.time.format.DateTimeParseException: could not be parsed, unparsed text found at index 10
Does someone have an understanding of Java Date API to help me out to grasp what I'm doing wrong here?
Thanks.
Asia/Qostanay is a zone which doesn't exist in the JDK8's list of timezones. It was added later.
If you don't care about the location of the timezone then just splice the [...] part of the string off the end before parsing. Knowing that the time is +06:00 is going to sufficient for almost all purposes.
Alternatively, upgrade to a more recent version of Java.
I am a beginner to programming. I am trying to run a simulation of a combustion chamber using reactingFoam.
I have modified the counterflow2D tutorial.
For those who maybe don't know OpenFOAM, it is a programme built in C++ but it does not require C++ programming, just well-defining the variables in the files needed.
In one of my first tries I have made a very simple model but since I wanted to check it very well I set it to 60 seconds with a 1e-6 timestep.
My computer is not very powerful so it took me for a day aprox. (by this I mean I'd like to find a solution rather than repeating the simulation).
I executed the solver reactingFOAM using 4 processors in parallel using
mpirun -np 4 reactingFOAM -parallel > log
The log does not show any evidence of error.
The problem is that when I use reconstructPar it works perfectly but then I try to watch the results with paraFoam and this error is shown:
From function bool Foam::IOobject::readHeader(Foam::Istream&)
in file db/IOobject/IOobjectReadHeader.C at line 88
Reading "mypath/constant/reactions" at line 1
First token could not be read or is not the keyword 'FoamFile'
I have read that maybe some files are empty when they are not supposed to be so, but I have not found that problem.
My 'reactions' file have not been modified from the tutorial and has always worked.
edit:
Sorry for the vague question. I have modified it a bit.
A typical OpenFOAM dictionary file always contains a Foam::Istream named FoamFile. An example from a typical system/controlDict file can be seen below:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
During the construction of the dictionary header, if this Istream is absent, OpenFOAM ceases its operation by raising an error message that you have experienced:
First token could not be read or is not the keyword 'FoamFile'
The benefit of the header is possibly to contribute OpenFOAM's abstraction mechanisms, which would be difficult otherwise.
As mentioned in the comments, adding the header entity almost always solves this problem.
Okay guys, I have, what I'm sure, is an entry-level problem. Still, I cannot explain it. Here's my code and its error:
> sample1 = readHTMLTable(http://www.pro-football-reference.com/boxscores/201609150buf.htm, which = 16)
Error: unexpected '/' in "sample1 = readHTMLTable(http:/"
It's having a problem with the second front-slash? Not only does every URL have two front-slashes, but I've poured through countless examples of this function, both on this site and others, and they've all formatted this code in this way. So, what am I doing wrong?
Additionally, I've tried it without the back-slashes:
> sample1 = readHTMLTable(www.pro-football-reference.com/boxscores/201609150buf.htm, which = 16)
Error: unexpected symbol in "sample1 = readHTMLTable(www.pro-football-reference.com/boxscores/201609150buf.htm"
Here, I'm not even sure which symbol it's talking about.
Please explain.
The issue is that you need to place your url in quotes (""). The following does return the table from your specified url:
sample1 = readHTMLTable("www.pro-football-reference.com/boxscores/201609150buf.htm")
As you probably know, the "which=" parameter is used to select which of the tables in that page you would like to retrieve. However my own attempts show that only 1 and 2 work. Could you tell me which table you are attempted to read into R? If this method doesn't end up working you can also attempt to read in the entirety of the webpage and parse out the table in question.
Hope this helps get things started!