I tried to plot graphs on MATLAB using GraphViz, using this GraphViz interface.
I keep getting this error:
>> [x,y]=draw_dot(G)
??? Attempted to access node_pos(2); index out of bounds because numel(node_pos)=1.
Error in ==> dot_to_graph at 94
y(lst_node) = node_pos(2);
Error in ==> draw_dot at 30
[trash, names, x, y] = dot_to_graph(tmpLAYOUT); % load NEATO layout
Whats really bugging me is that it worked great before (on my old computer).
Any idea how to solve this problem?
After debugging, I find the solution.
Just find the line 92 in dot_to_graph.m, as written:
[node_pos] = sscanf(line(pos_pos:length(line)), ' pos = "%d,%d"')';
Change the %d,%d to %f,%f. Because there are float numbers in the dot file.
This is difficult to answer completely since you are not giving us the G you are using, so we can't reproduce your problem directly; I'll attempt to answer anyhow "on the dry":
The error messages you get mean that the temporary DOT files created by neato in draw_dot can not be read properly; a line in the dot file which is parsed by dot_to_graph using the format string pos = "%d,%d" is expected to contain two numbers, e.g pos ="42,3", but MATLAB's sscanf only reads one number from that line.
Is it possible that your new computer uses a different language setting, i.e. using a decimal comma instead of a decimal point? This might cause Matlab to read the two numbers as one, not sure how sscanf adapts to local decimal point settings.
Otherwise, are you still using the same version of neato as before? Could it be that its output format has changed in some way?
The best way to find out might be to set a debugging break point in the offending line 94 ([node_pos] = sscanf(line(pos_pos:length(line)), ' pos = "%d,%d"')';) and check what line(pos_pos:length(line)) evaluates to.
Related
User made some calculations using program..and printed it on paper.. But mouse cut some part from the paper.
Now we have to create the program to find missing values.
Example:
54 + 27 = HOLE
3241 + 4HOLE45=7281
We have to find the missing value at HOLE.
If we pass multiple eqution at a time.
If (like in your example) the equations are separated by line breaks (or any other character will work) simply separate the equations maybe into custom objects then you can split each equations to numbers by splitting at every arithmetic symbols.
What I am suggesting is to phrase each line as an equation and find the missing bit by comparing both sides of the equal sign. You can find any one missing number each from any equation like this.
I have not provided any code example because you have not provided any code that you have currently tried out and also no specific language is specified. If you follow up with those I am ready to give a code sample.
In MatLab (R2015a), I want to style the title of my plots using latex.
This is working fine for some functions, but not if there's a power in the equation.
The below code works, and shows a formatted title to the right, and an unformatted title to the left.
It shows the warning:
Warning: Error updating Text.
String must have valid interpreter syntax: y = x^2
syms x y
eq = y == x^2;
subplot(1,2,1)
ezplot(eq)
title(latex(eq),'interpreter','latex')
eq = y == x+2;
subplot(1,2,2)
ezplot(eq)
title(latex(eq),'interpreter','latex')
EDIT:
I just found out I can get it to work by appending $ on both sides. But it seems weird that I would have to do this.
So this works:
title(strcat('$',latex(eq),'$'),'interpreter','latex')
Solution
The problem can be solved easily by adding $-signs before and after the generated LaTeX-expression. So you can change your «title-lines» to:
title(['$',latex(eq),'$'],'interpreter','latex')
An alternative is to use strcat as proposed in your question.
Explanation
Since you basically answered the question yourself already, I'm going to explain why it happened. Hopefully after reading this, it's no longer 'weird' behaviour. If you choose to use the LaTeX-interpreter in Matlab, you really get a LaTeX-interpreter. This means that the provided string must be valid LaTeX-syntax.
Using ^ outside a math-environment is considered invalid syntax because it is a reserved character in LaTeX. Some interpreters automatically add the $ before and after in this case, but throw a warning at the same time.
The output of the latex-function in Matlab is provided without the $-signs. This way you can combine outputs and concatenate if needed without creating a mess with $-signs.
To change to the math-environment in LaTeX you can use the already mentioned shortcut $...$. An alternative way is to use \begin{math} your_equation \end{math}. It produces the same result for your equations and can be used here for demonstration purposes. The following line would do the same job, but is a bit longer to write:
title(['\begin{math}',latex(eq),'\end{math}'],'interpreter','latex')
Now, the reason why only one of your equations is displayed correctly, lies in the invalid character ^ in y = x^2. Matlab then chooses interpreter none and therefore displays the string unformatted. The +-sign in y = x + 2 is valid outside a math-environment, so it gets displayed correctly (but is not interpreted in a math-environment).
I've got a Subscripted assignment dimension mismatch problem.
I've already localized the issue, and know exactly what is going on, I just don't know why.
Here's the problematic piece of code:
mFrames(:,i) = vSignal(round(start:1:frameLength*samplingRate));
start=start+frameShift*samplingRate;
frameLength = frameLength+frameShift;
I've already checked what's going on in debugmode; usually my resulting column length of mFrames is 128, this stays the same until i=1004. Then, my column length changes to 127.
I've checked the values involved while in debug mode, and it simply does not make sense what is going on. At i==1004 start=32097 and frameLength*samplingRate=32224.
That's a difference of 127 meaning 128 points, that should work.
BUT when i assign a vector A=round(start:1:frameLength*samplingRate)
OR B=start:1:frameLength*samplingRate
In both cases I get a vector going from 32097 to 32223. This ALTHOUGH when I give in frameLength*samplingRate matlab is giving me 32224.
In other words, matlab is telling me it's using one number, but when I test I find it's using a different one.
Any help appreciated.
I suspect your 32224 is not actually 32224. MATLAB's default format only displays so many decimal places, so when dealing with floating point numbers, what is printed on screen is not necessarily the "exact" value.
Let's go back a step and look at how the synatx x = start:step:end works.
1:1:10 should give us numbers in steps of 1 from 1 to 10. Fair enough, that makes sense. What if we set the end value to something that's slightly above 10?
e.g.:
1:1:10.1
Well, it still gives us 1:1:10, (or 1:10, 1 being the default step) because we can't have values higher than the end-point, so 11 isn't a correct step.
So what about this:
1:1:9.99
Spoiler: it's the same as 1:9
And this?
1:1:9.9999999
Yep, still 1:9
But if we do this:
a = 9.9999999;
Then with default format, the value of a will be shown on the command line and in your list of workspace variables as 10.0000.
Now, if frameLength and samplingRate are both stored as floating point numbers, it's possible that the number you see as 32224 is not 32224 but very slightly below that. You can check this by changing your default format - e.g. format long at the command line - to show more decimal places.
The simplest solution is probably to do something like:
B=start:1:round(frameLength*samplingRate)
Or try to store the relevant values as integers (e.g., uint32).
I'm trying to write a bit of code of to make MATLAB scatter plots from variables in a structure. I want to give the code the name of the structure (there will be many of these structures) and then get it to make a scatter plot of two variables. When I try the code below I get an error message saying, "??? Error: File: make_graphs.m Line: 6 Column: 9
The input character is not valid in MATLAB statements or expressions."
str2stuct= input('Please enter the string for the struct e.g. TMB_RUN_1_data:');
test1=strcat(str2stuct,'.NDROP_max');
test2=strcat(str2stuct,'.input_kappa');
scatter($(test2), $(test1))
I thought that the error message probably meant that I was using the dollar sign in a way which MATLAB doesn't approve of (I've yet to find much use for $ in MATLAB).
I tried it like this:
str2stuct= input('Please enter the string for the struct e.g. TMB_RUN_1_data:');
test1=strcat(str2stuct,'.NDROP_max');
test2=strcat(str2stuct,'.input_kappa');
scatter((test2),(test1))
And got this error:
"??? Error using ==> scatter at 51
Must supply X and Y data as first arguments.
Error in ==> make_graphs at 6
scatter((test2),(test1)) "
I tried it with changing the last line as shown below but got the same error as with the brackets:
scatter(test2,test1)
If I use the literal name as below it works fine.
scatter(TMB_RUN_1_data.NDROP_max,TMB_RUN_1_data.input_kappa)
I've tried a bunch of other things but I am not getting it. I've tried the mathworks pages on scatter but there are no examples that are close to what I am doing. I am really really stuck.
EDIT: I have found a solution but I am aware that this is not considered best practice. If you can simply explain how to do this better that would be good. Answers should be aimed at a moron in a hurry, not an experienced programmer.
Making this the last line works:
scatter(eval(test2),eval(test1))
I am aware that 'eval' is frowned upon and so this probably isn't a good long term answer, works for now. This seems to be the way to get MATLAB to actually read the contents of the strings test1 and test2 into the lines in question.
The HITRAN database is a listing of molecular rotational-vibrational transitions. It is given in a text file where each line is 160 characters, with fixed width fields defining molecule, isotope, etc. The format is well documented, and there is even a program on the MathWorks File Exchange that will read in the database and simulate a portion of the spectrum. However, I need to read in a specific portion of the spectrum and then use it to do some fitting to a measured spectrum, so I need something much more custom.
As given in the comment section of that function, as well as elsewhere, the following line should read each line in properly:
database = which('HITRAN2012.par');
fid = fopen(database);
hitran = textscan(fid,'%2u%1u%12f%10f%10f%5f%5f%10f%4f%8f%15c%15c%15c%15c%6c%12c%1c%7f%7f','delimiter','','whitespace','');
fclose(fid);
The first two fields denote the molecule code, which runs from 1-47, and the isotope code which runs from 1-9.
Unfortunately, molecules 1-9 do not have a leading zero, and no matter what I do, it seems to silently confuse MATLAB. If I load in the entire database and then type
unique(hitran{1})
I do not get the numbers 1-47, but I get 10-92 with a few numbers missing. As far as I can figure, when MATLAB encounters a leading space, it shifts the line over and then pads the end, so that ' 12' becomes '12', but I'm not exactly sure. I have also tried
hitran = textscan(fid,'%160c','delimiter','\n','whitespace','');
and then tried to parse the resulting strings, but that also sometimes gets confused by the first space.
For instance, the first water line looks like
exampleHitranLine = ' 14 0.007002 1.165E-32 2.071E-14.05870.305 818.00670.590.000000 0 0 0 0 0 0 7 5 2 7 5 3 005540 02227 5 2 0 90.0 90.0';
The first bit of code comes across this line and returns '14' instead of ' 1' and '4'. If I just read in a subset that only contains molecule 1 (as in this example), then the second method of reading works fine. If I try to read in the entire database, however, the lines with molecule 1-9 are shifted the the left, which messes up all the other fields.
I should note that I've tried reading the numerical fields both as floats and as integers, and neither gives satisfactory results. The entire database in text form is nearly 700 MB, and so I need something that works as efficiently as possible.
What am I doing wrong?
I have a new file on the FileExchange that will read in HITRAN 2004+ format data. Please try it out and let me know if there are any issues with it.
I don't have an answer as to why this is happening, but I do have a solution. If anyone has an answer as to why, I'd be happy to accept it.
It is the leading space that is screwing things up. MATLAB is being a little too clever, and when textscan encounters a leading space, it decides that it's extra and discards it and moves on to the next two characters. To get it to properly read in the file, I had to go line by line and test whether the first character is a space and then replace it with a leading zero, like this:
database = which('HITRAN2012_First100Lines.par');
fileParams = dir(database);
K = fileParams.bytes/162;
hitran = cell(K,19);
fid = fopen(database);
for k = 1:K
hitranTemp = fgetl(fid);
if abs(hitranTemp(1)) == 32;
hitranTemp(1) = '0';
end
hitran(k,:) = deal(textscan(hitranTemp,'%2u%1u%12f%10f%10f%5f%5f%10f%4f%8f%15c%15c%15c%15c%6c%12c%1c%7f%7f','delimiter','','whitespace',''));
end
fclose(fid);
I'm working in MATLAB 2013a. Should I consider this to be a bug and report it? Is there some reason that the leading space should be gobbled up like this?
Update:
My workaround above was slow, but worked. Then I had to process the HITEMP database, which is several times larger, so I finally did submit a support ticket to MathWorks. The workaround suggested by MathWorks technical support is to read everything in as text and then convert. This saves a lot of disk reads and works.
fileParams = dir(database);
fid = fopen(database);
hitran = textscan(fid,'%2c%1c%12c%10c%10c%5c%5c%10c%4c%8c%15c%15c%15c%15c%6c%12c%1c%7c%7c','delimiter','','whitespace','');
fclose(fid);
moleculeNumber = uint8(str2num(hitran{1}));
isotopologueNumber = uint8(str2num(hitran{2});
vacuumWavenumber = str2num(hitran{3});
...
etc.
Depending on the application, for larger databases one would probably want to do this in chunks rather than all at once.
He also said he would forward the behavior to the development team for consideration in a future update.