I generated random values using following function :
P = floor(6*rand(1,30)+1)
Then, using T=find(P==5), I got values where outcome is 5 and stored them in T. The output was :
T =
10 11 13 14 15 29
Now, I want to calculate the mean value of T using mean(T) but it gives me following error :
error: mean(29): out of bound 1 (dimensions are 1x1) (note: variable 'mean' shadows function)
What I am trying to do is to model the outcomes of a rolling a fair dice and counting the first time I get a 5 in outcomes. Then I want to take mean value of all those times.
Although you don't explicitly say so in your question, it looks like you wrote
mean = mean(T);
When I tried that, it worked the first time I ran the code but the second and subsequent times it gave the same error that you got. What seems to be happening is that the first time you run the script it calculates the mean of T, which is a scalar, i.e. it has dimensions 1x1, and then stores it in a variable called mean, which then also has dimensions 1x1. The second time you run it, the variable mean is still present in the environment so instead of calling the function mean() Octave tries to index the variable called mean using the vector T as the indices. The variable mean only has one element, whose index is 1, so the first element of T whose value is different from 1 is out of bounds. If you call your variable something other than mean, such as, say, mu:
mu = mean(T);
then it should work as intended. A less satisfactory solution would be to write clear all at the top of your script, so that the variable mean is only created after the function mean() has been called.
Related
I must calculate a function on EES.
Function: T(t)=((T_surface-T_infinity)*(e^(-bt)))+T_infinity
t is time and limits are between 1 and 40 second. I need calculate every seconds in 1-40.
How can I write this function in EES?
If I understand the question correctly, no differential equation should be solved, no integration, summation or the like should be carried out. Only a calculation with variation of the variable t is to be accomplished.
There are two possibilities. But first: EES is not 'key-sensitive'! So you should choose one—T or t—and the other should get another 'name'. I prefer 'tau' for time.
Parametric table
Write the equation in the equation window and aad the parameter you may have(?). Do not define 'tau'. like:
T=((T_surface-T_infinity)*(exp(-b*tau)))+T_infinity
T_surcace = 80[C]
T_infinity = 20[C]
b=3
Then open the parametic table, add the variables you want to see. At least you should take T and tau. Expand the rows of the table to 40 and enter the respective times. Then press the green play-button (top left in the table).
Duplicate function:
T_surface = 80[C]
$varinfo tau[] units='s'
b=0.1[1/s]
Duplicate i=1,40
tau[i] = i*1[s]
T[i]=((T_surface-T_infinity)*(exp(-b*tau[i] )))+T_infinity
End
T_infinity = 20[C]
$varinfo T[] units='C'
I don't understand why this array:
Type = Reflective Event, Reflective Event, Reflective Event
according to Octave's variable editor is a 3x19 char array.
In the variable editor, Type is shown as follows (I don't know if that's helpful)
TYPE =
Reflective Event
Reflective Event
Reflective Event
The thing is odd, in fact when I code disp(size(TYPE)) I get 3 19 accordingly.
Now, the even wierder thing is that, if I then code size(TYPE,1) which should give the size of TYPE's first dimension, I instead get 1 1.
Can you guys help me figure out what is wrong here?
Just guessing, as the syntax in the post is invalid Octave:
Your variable is actually a matrix of chars. Note that a string is simply an array of independent chars. so
var1=" Reflective Event, ";
is a length(var1)==19 array, or a size(var1)==(1,19) array. Now, if you repeat that, you can either make a (1,19*3) array, or a (3,19) matrix, which I assume is what you have.
Now, as you did not know that each char is individual, you reached the wrong conclusion with your second test. When you index a matrix using linear indices (i.e. a single index), it will "unroll" the array and give you that single elements.
i.e. A=[1 2 3; 4 5 6; 7 8 9] is a 3x3 matrix, but you can do A(2,1) or just A(4) to access the value 4.
In your test size(TYPE(1)) is (1,1), because TYPE(1)==" ", as TYPE(3)=="e" and so on.
I'm relatively new to Scilab and I would like to find the indices of a number in my matrix.
I have defined my number as maximal deformation (MaxEYY) and on displaying it, it is correct (I can double check in my *.csv file). However, when I want to know exactly where this number lies in my matrix using the find command, only (1,1) is returned, but I know for a fact that this number is located at (4,8).
My matrix is not huge (4x18) and I know that this number only occurs once. On opening the *.csv file, I removed the headers so there is no text.
Can anyone help me with this?
N=csvRead("file.csv",",",".",[],[],[],[],1)
EYY=N(:,8);
MaxEYY=max(EYY);
MinEYY=min(EYY);
[a,b]=find(MaxEYY);
disp([a,b]);
First, you need to understand how find() works: it looks for values of true or false in a matrix. So if you want to find a certain value in it, you should do find(value == matrix).
Then, notice that in your code, you are applying find() to MaxEYY, which is a single value, that is, a scalar, a 1-by-1 matrix. When you do that, you can only get (1,1) or [] as results.
Now, combining these two informations, this what you should've done:
[a, b] = find(EYY == MaxEYY);
Also, there is a quicker way to get this indices: max() can also return the indices of the maximum value by doing
[MaxEYY, inds] = max(EYY);
And the same goes for min().
This is my first time trying to complete work in Octave. I have attempted to complete "for loops" to get the mean of each and then subtract this to centre the results in the 25 samples of the 5 items. I get the right figures, however I also get an out of bounds error (indicated below). Can anyone help me please?
error: TrialPartB: A(I,J): row index out of bounds; value 6 out of bound 5
You have populated your G_all structure with only 5 data members, but then, when you calculate the mean, you loop i=1:25. There are only 5 members, so when it gets to member 6, it fails with the 'row index out of bounds' error.
You need to limit the for loop to be just the size of the data, perhaps using rows(G_all) instead of 25 as the limit of the loop.
As rolfl already explained you are trying to access row 1..25 but G_all only has 5 rows.
But apart that problem you shouldn't calculate mean in a for loop but use the function "mean" instead.
a=[4 1 6];
mean(a)
ans = 3.6667
If you want to remove the mean from an vector just use "detrend":
detrend(a, 0)
ans =
0.33333 -2.66667 2.33333
I have been trying to convert my level-1 S-function to level-2 but I got stuck at calling another subfunction at function Output(block) trying to look for other threads but to no avail, do you mind to provide related links?
My output depends on a lot processing with the inputs, this is the reason I need to call the sub-function in order to calculate and then return output values, all the examples that I can see are calculating their outputs directly in "function Output(block)", in my case I thought it is not possible.
I then tried to use Interpreted Matlab Function block but failed due to the output dimension is NOT the same as input dimension, also it does not support the return of more than ONE output................
Dear Sir/Madam,
I read in S-function documentation that "S-function level-1 supports vector inputs and outputs. DOES NOT support multiple input and output ports".
Does the second sentence mean the input and output dimension MUST BE SAME?
I have been using S-function level-1 to do the following:
[a1, b1] = choose_cells(c, d);
where a1 and b1 are outputs, c and d are inputs. All the variables are having a single value, except d is an array with 6 values.
Referring to the image attached, we all know that in S-function block, the input dimension must be SAME as output dimension, else we will get error, in this case, the input dimension is 7 while the output dimension is 2, so I have to include the "Terminator" blocks in the diagram for it to work perfectly, otherwise, I will get an error.
My problem is, when the system gets bigger, the array d could contain hundreds of variables, using this method, it means I would have to add hundreds of "Terminator" blocks in order to get this work, this definitely does not sound practical.
Could you please suggest me a wise way to implement this?
Thanks in advance.
http://imgur.com/ib6BTTp
http://imageshack.us/content_round.php?page=done&id=4tHclZ2klaGtl66S36zY2KfO5co