Problems using matlab to print a histogram to a file - linux

I am trying to create a histogram of numbers in an array. I am using Matlab to do this. I am connecting via ssh so I can only use Matlab in the terminal on my Linux computer. I am trying to create a histogram of the data in the array and save it as a .png. I know that in order for me to save this I need to use the print function. So far my attempt has been the following:
h=hist(array)
print(h,'-dpng','hist1.png')
which told me that there is no variable defined as -dpng but I thought that the point of that was to specify the file type.
Then I just deleted the -dpng and ran it as
print(h,'hist1.png')
to which it told me "Handle must be scalar, vector, or cell-array of vectors"
At this point I don't quite know what to do next. I would like for someone to help me figure out how to print this histogram to a .png file. Thank you.


hist does not return a figure handle, you could to do something similar to:
h = figure;
hist(array);
print(h, '-dpng', 'hist1.png');
to save the histogram.


By itself, the function hist(array) plots a histogram. If you assign the output to a variable, it returns the binned values of array, not the handle to your plot.
f = figure;
hist(array)
saveas(f,'hist.png')


you may would like to output the array to a csv file.
fid = fopen('file.csv','wt');
for i=1:size(arr)
fprintf(fid, '%s,%d,%d\n','element number' ,i ,arr(i));
end
fclose(fid);
See this link, you should be able to change the answers there to your needs: Outputing cell array to CSV file ( MATLAB )


You don't need to use figure handle unless you want to print not current figure. By default print uses gcf that returns handle for current figure.
So you just can do:
hist(array)
print('-dpng','hist1.png')
You got an error that there is no variable defined as -dpng probably because you forgot one quote symbol and used -dpng'.

Related

Is there a way to compare the format in which a line of a text file was written in Fortran?

I'm developing a Fortran program that must obtain some data from a text file and generate another text file using specific data from the first one.
The input file have many lines written in several specific formats which I know of. Although I know the formats, the lines in this file are generated in a "random way".
It would be much easier to generate the output file if I could compare the format in which each line was written, then I would know exactly what data I can get from that line of the input file to use it in the output file.
What I need is something like, for example, knowing that the format of the line read and stored in the LINHA variable is described in the FORMATO variable, do something like:
    
IF (FORMATO = '(1X, 15,3F8.1,2 (5A, 1X))') THEN
READ (LINHA, '(6X, F8.1)') my_variable
END IF
Because there might be another format such as
'(6A, 2F8.1, F8.6,2 (6A))'
in which, if I use the same READ statement, I will read an F8.1 variable in my_variable, however this value is not the correct one.

A (not so elegant) work-around that I can think of is to read the entire line using the advance = no option of read() and parse each character in the line separately. While doing so, you may count white spaces or other specific characters that you know of and then identify the different formats from there.
It would be helpful if you could give more specifications of the nature of the task.

The best option is to read without format, keeping each line in a character array. Then read the line variable as an internal file with the required format using the variable IOSTAT in order to check if the format is the correct.
INT max_size = 80
CHARACTER(LEN=max_size) :: line
READ(*,*) line
READ(line,'(1X, 15,3F8.1,2 (5A, 1X))',IOSTAT=ios) var1, var2, ...

Problem solved using a mixture of some of the suggestions posted.
I read each of the lines of the input file in an internal variable (RLINFILE) in the format '(A165)'. After that, I read all the contents of the string that I put in this internal variable in several dummy variables, using the format I knew of the lines from where I wanted to get some information (read all the information of the line in the desired and get IOSTAT = 0 guarantee that this is the correct line), so if the result of the reading is ok (IOSTAT = 0), it is because the line I just read was the correct one for the information I wanted, so I store the contents of some of the dummy variables that represent the values that interest me. In the code, the solution looked something like this:
OPEN(UNIT=LU1,FILE=RlinName,STATUS='OLD')
ilin = 0
formato = '(14X,A,1X,F7.1,1X,F7.1,5X,A,1X,A,1X,A,5X,A,I5,1X,A,I3,3F8.1,A,A,A,1X,A,2(1X,F8.2),1X,A,1X,A)'
DO WHILE (.TRUE.)
READ(LU1,'(A165)',END=300) RLINFILE
READ(RLINFILE,formato,IOSTAT=linhaok) dum2_a1,dum2_f1,dum2_f2,dum2_a2,dum2_a3,dum2_a4,dum2_a5,dum2_i1,dum2_a6,dum2_i2,dum2_f3,dum2_f4,dum2_f5,dum2_a7,dum2_a8,dum2_a9,dum2_a10,dum2_f6,dum2_f7,dum2_a11,dum2_a12
IF(linhaok.EQ.0) THEN
ilin = ilin+1
rlin_lshu(ilin) = dum2_a4
rlin_nbpa(ilin) = dum2_i1
rlin_ncir(ilin) = dum2_i2
rlin_ppij(ilin) = dum2_f3
rlin_pqij(ilin) = dum2_f4
rlin_tapn(ilin) = dum2_a7
END IF
END DO
300 CLOSE(UNIT=LU1)

The description of the problem you are trying to solve is a bit vague to me, but the simplest solutions that comes to my mind, given the description of the problem, is to modify the original code that generates the input data file, to write the used Fortran READ format before the data line in the input file. This way, you can read the format as a string and use it in the subsequent data IO in your second code.
If you describe the specific task your tryting to accomplish in more details, perhaps more experienced Fortranners could help.

Using bessel functions in MATLAB

I'm trying to put all of my functions from Excel workbook into MATLAB. I'm having an issue using bessel functions in MATLAB. I'm simply not getting the same results from MATLAB as I do in excel.
For example, in excel if I execute
=0.32*BESSELI(0.32,0)/2/BESSELI(0.32,1)
I get 1.012.
When I use the same approach in MATLAB
0.32*besseli(0.32,0)/2/besseli(0.32,1)
I simply get zero.
Can someone please help me integrate bessel functions into my MATLAB script so that they provide the same answer as they do when used in excel?

MATLAB and Excel have the arguments of the besseli function in a different order.
The following expression (note the order of arguments changed):
0.32*besseli(0, 0.32)/2/besseli(1, 0.32)
will yield:
> ans = 1.0127
in MATLAB.

The documentation shows the formulae and show that if you use Z=0, which you have in your first besseli, you should get 0, which you do. The second call to besseli should not get you zero, and indeed it does not:
besseli(0.32,1)
ans =
1.0744
I copied the following from the aforementioned documentation:
This shows that unless your nu (that Greek thing that looks like a v) is zero, your modified Bessel function of the first kind at Z=0 will be, in fact zero.
On a side note: why are you doubly dividing and not simply writing
0.32*besseli(0.32,0)*besseli(0.32,1)/2

How to save strings in matrixes in matlab

I want to have a matrix/cell, that has strings inside that I can access and use later as strings.
For instance, I have one variable (MyVar) and one cell (site) with names inside:
MyVar=-9999;
site={'New_York'; 'Lisbon'; 'Sydney'};
Then I want to do something like:
SitePosition=strcat(site{1},'_101'}
and then do this
save(sprintf('SitePosition%d',MyVar),);
This doesn't work at all! Is there a way to have strings in a matrix and access them in order to keep working with them if they were a string?

This:
MyVar=-9999; site={'New_York'; 'Lisbon'; 'Sydney'};
SitePosition = strcat(site{1},'_101');
save(sprintf('SitePosition%d',MyVar));
Works fine and yields SitePosition-9999.mat, note the syntax changes in lines 2 and 3.
Is there something else you're expecting?
EDIT: Based on your comment
Check out the documentation for save regarding saving specific variables
New example:
MyVar=-9999;
site={'New_York'; 'Lisbon'; 'Sydney'};
SitePosition = strcat(site{1},'_101');
save(SitePosition,'MyVar');
Creates New_York_101.mat with only the variable MyVar in it.

Same for loop, giving out two different results using .write()

this is my first time asking a question so let me know if I am doing something wrong (post wise)
I am trying to create a function that writes into a .txt but i seem to get two very different results between calling it from within a module, and writing the same loop in the shell directly. The code is as follows:
def function(para1, para2): #para1 is a string that i am searching for within para2. para2 is a list of strings
with open("str" + para1 +".txt", 'a'. encoding = 'utf-8') as file:
#opens a file with certain naming convention
n = 0
for word in para2:
if word == para1:
file.write(para2[n-1]+'\n')
print(para2[n-1]) #intentionally included as part of debugging
n+=1
function("targetstr". targettext)
#target str is the phrase I am looking for, targettext is the tokenized text I am
#looking through. this is in the form of a list of strings, that is the output of
#another function, and has already been 'declared' as a variable
when I define this function in the shell, I get the correct words appearing. However, when i call this same function through a module(in the shell), nothing appears in the shell, and the text file shows a bunch of numbers (eg: 's93161), and no new lines.
I have even gone to the extent of including a print statement right after declaration of the function in the module, and commented everything but the print statement, and yet nothing appears in the shell when I call it. However, the numbers still appear in the text file.
I am guessing that there is a problem with how I have defined the parameters or how i cam inputting the parameters when I call the function.
As a reference, here is the desired output:
‘She
Ashley
there
Kitty
Coates
‘Let
let
that
PS: Sorry if this is not very clear as I have very limited knowledge on speaking python

I have found the solution to issue. Turns out that I need to close the shell and restart everything before the compiler recognizes the changes made to the function in the module. Thanks to those who took a look at the issue, and those who tried to help.

Use stats inside Gnuplot inline functions

I can't figure out if it is possible to do something like
f_L0(FL)=(stats FL using ($8) name "L", \
L = L_mean, \
1)
Gnuplot keeps complaining: ')' expected and points to FL inside the function.
Any ideas how to define some function like this?
p.s. my gnuplot is 4.6 (Feb2014).
UPDATE:
since this is not possible, it seems, i would just do some analysis in Octave and output it to the file :)

No, you cannot use stats inside of inline funcitons. Gnuplot functions are very basic and can contain only 'regular' mathematical function which compute a single numerical value. You cannot get access to data files inside of functions.
The stats command is command, which is the only command besides plot and splot which has access to data files.
The use of stats is as follows: You must use it as standalone command like
stats 'filename' using 8 name "L"
after which you have access to many variables which contain results from calculations on your data (column 8 in file filename). L_mean is one of those variables, for more see show variables after having executed stats.
However, you can do many calculations inside the using statement. To subtract the mean from you data, use e.g.:
stats 'filename' using 8 name "L"
plot 'filename' using ($8-L_mean)

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