I am working on a calculator program for a geometry midterm project. It involves making 5 programs for commonly used equations. One of my programs is exponential growth. The prompts in the beginning appear and work, but when I try to have the program solve the equation, a Syntax Error pops up.
I am using the TI-84 Plus calculator and the TI Connect CE software to do the programming.
My code:
Lbl 4
ClrHome
0→I
0→G
0→O
Input "ORIGINAL AMT.=",I
Input "GROWTHRATE(Dec.)=",G
Input "PERIOD OF TIME=",Q
Goto M
Lbl M
ClrHome
Output(I(1+G))^(Q)
Pause
ClrHome
Menu("TRY AGAIN?","YES",4,"NO",6)
Any help would be greatly appreciated.
You are using the mistakenly using the Output( command instead of Disp. Try replacing Output(I(1+G))^(Q) with Disp I(1+G)^Q like so:
Lbl 4
Input "ORIGINAL AMT.=",I
Input "GROWTHRATE(Dec.)=",G
Input "PERIOD OF TIME=",Q
ClrHome
Disp I(1+G)^Q
Pause
ClrHome
Menu("TRY AGAIN?","YES",4,"NO",6
Related
I am using MATLAB R2015 and cannot implement 'butter' without getting an error related to too many output arguments from the polyfit part of the script. I have used the same implementation for years with other versions of MATLAB.
Example:
[b, a] = butter(2,[.15,.3]);
Error using poly
Too many output arguments.
Error in zp2ss (line 127)
den = real(poly(p(i:i+1)));
Error in butter (line 97)
[a,b,c,d] = zp2ss(z,p,k);
I get the same error implementing the examples in the help documentation.
Just a guess but is there any chance you've defined your own poly function? which('poly') should point to some Matlab directory unless you've defined it elsewhere, potentially as a variable?. For me on a newer version that path is something like $MATLAB/toolbox/matlab/polyfun/poly.m You can also edit the poly function edit poly and verify that there is one output argument for the function.
Also, I'd advise against ever writing decimal numbers without a leading zero. It took me way to long to figure out what [.15,.3] was. Instead write [0.15,0.3] or even just [0.15 0.3] Edit: I just realized that is an example in Matlab ... my point stands but the toolbox author should know better ...
Is there a way in MATLAB to prepare a command programmatically (ie. writing a command directly to the command prompt) so the user can execute it by pressing an enter?
I want to implement my own "Did you mean:" functionality, that is built into MATLAB already.
It can be done using Java from Matlab to programmatically generate key events, along the lines of this answer.
Let's say the command you want to "prepare" is dir. Then
commandwindow; %// make Matlab command window have focus
robot = java.awt.Robot; %/ Java Robot class
robot.keyPress (java.awt.event.KeyEvent.VK_D); %// key press event
robot.keyRelease (java.awt.event.KeyEvent.VK_D); %// key release event
robot.keyPress (java.awt.event.KeyEvent.VK_I);
robot.keyRelease (java.awt.event.KeyEvent.VK_I);
robot.keyPress (java.awt.event.KeyEvent.VK_R);
robot.keyRelease (java.awt.event.KeyEvent.VK_R);
will type dir onto the command window, exactly as if the user had written it. Then pressing Enter will run the command.
The short answer is no. This can't be done as you want it to. What you are trying to do is to write text to MATLAB's stdin and let it remain there unprocessed. Essentially a modified form of piping.
The closest option available in MATLAB is Evaluate Selection where when you select text you can cause MATLAB to execute it in the command prompt. MATLAB puts this text exactly where you want it but it also immediately executes it. There does not seem to be a way to halt this or emulate its functionality programmatically.
Writing to stdin in MATLAB is not allowed as you can see from
>> fprintf(0, 'help conv')
Error using fprintf
Operation is not implemented for requested file identifier.
where 0 denotes stdin, 1 denotes stdout and 2 denotes stderr. Another naive attempt would be to use fopen()
>> fid = fopen(0, 'w');
Error using fopen
Invalid filename.
but alas this fails too. However, we can see from the first attempt that what you desire
is not implemented
The only option to get exactly what you want is that possibly with some MATLAB hackery the ability is there but I'm not aware of it or anybody who has even attempted it.
EDIT: Luis Mendo has provided the MATLAB hackery solution I was talking about.
The closest you could get to what you want is to use hyperlinks to run MATLAB commands like
>> disp('Did you mean: conv()')
Did you mean: conv()
ans =
12
where conv() is a hyperlink and clicking on it will execute conv(a,b) where a = 3; and b = 4; in this example.
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.
How i can execute an equation from GUI?
Example:
How i can do this with various type of equation?
Thanks the answers.
I'm not entirely sure what you mean, but I think you want to grab the equation that a user types in to a text box and turn it in to a function?
Why does your F change from 3 arguments to 4? i.e. F(x,y,y') --> F(1,0,5,-1) in the next line? (The examples of F you gave don't seem to match up with your equation..)
In any case, check out eval(), perhaps that is what you want.
It takes in a matlab command as a string, e.g. 2 + 3, and evalutes it.
So
eval('2+3') % gives 5
eval('f=#(x,y,ydash) y*sqrt(1+ydash^2)') % gives a function f
f(1,5,-2) % gives 11.1803
But in any case, how do you expect the user to type in the square root symbol and the squared symbol? The eval() approach relies on them typing in syntax that matlab will understand.
If you clarify your question a bit more this will be easier.
I have matlab m file which plots 3 graphs using subplot. Now i also have a UNIX script which invokes this script and passes the function name as parameter.
I have two problems:
I am getting the warning Type-ahead buffer Overflow
The plot remains only for a few seconds before disappearing. How can I keep plot active til l user clicks on cross button?
thanks!
It's hard to answer your first question without some code.
You can use the pause command to wait for the user to press any key.