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.
Related
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.
I am currently having an equation that contains 4~5 variables, and I am unfamiliar with matlab. I want to see how a variable change with the other variable fixed (might assign them some value). Maying graphing them out will help. I found it cumbersome to work in the main GUI in matlab, this is mainly after I type in my equation, I didn't know if the expression is what I want because of missing brackets, etc.
Recently I found mudpad, it is better because it will show you the expression in pretty form. I am wondering is there any other tool-box that is more suitable for my intention?
Update:
Ps=1;
Pr=1;
Pd=1;
g=0.25;
d1=1;
d2=1;
n=0.18;
Yr = #(x)(Ps)/(d1*((Pd*g^2)/d2 + (n*(x- 2))/(x- 1)));
Yr_=ezplot(Yr,0,1);
There is actually 4 more equations to plot and I am only posting one of them.
I'm having the following issue with my code. I've been trying to use some other posts that I found on line, like this one. But they didn't what I'm looking for.
My code uses a MATLAB Exchange function which optimize a numerical value that is important to be with 32 digits after the dot such as
0.59329669191989231613604260928696
The optimization function can be found here and it is called fminsearchbnd
The optimization function calculate this and store the value in a variable that I use all over my code. In order not to perform the optimization everytime I want to store the variable (I tried either on a *.mat and on a label in the string form.
But when I retrieve it, MATLAB transforms it in a double precision variable 'cutting' all the numbers after the 14th. However I need all of them because they are important!
Is it possible to read a number like that w/o using vpa() because with a symbolic value I can't do anything.
Any help is really appreciated.
Thanks
EDIT:
fminsearchbnd gives me this class(bb) -> double and when I want to see it on the workspace it is 0.586675392365899. But when I set formatSpec = '%.32f\n'; because I want to see all the numbers that the optimization gives me, typing set(editLabel,'String',num2str(bb,formatSpec))
You're trying to store/use a number that cannot be represented exactly in an IEEE754 64-bit double-precision floating point number.
I'm not sure how you got that number without using vpa() in the first place, since 64-bit double is Matlab's maximum of precision...
You could use the multiple precision toolbox by Ben Barrowes, or HPF by John d'Errico, also from the FEX. You'll have to convert/construct to/from string if you want to store/load it to/from file.
But I have to agree with John's comment there:
The fact is, most of the time, if you can't do it with a double, you
are doing something wrong
so...why exactly are those 32-or-more digits important?
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.