My code is the following, I would like a to assume iteratives values like '3' , '4' and so on. My code is like:
a=2
#perform some basic operation like:
b=a*2
#convert it to string
c=str(b)
p path1 u 1:($1<=0?$#c:1/0) w filledcurves y=0
The solution proposed on similar topic here so far did not work.
You should use this syntax
c=''.b
c will be equal to 'b'
gnuplot provides both sprintf (as in the C language routine) and a private implementation gprintf that offers formatting options beyond the normal ones provided by the C language. The full details with all supported format options are in the gnuplot documentation. A very simple use would be:
c = sprintf("%8.3f", b)
However, it makes no sense to convert the value to a string if your intent is to use it in a plot command that expects a number. There is no iteration in the pseudo-code you show so I can't guess exactly where you are headed with this but note that the operation #c to evaluate c as a macro expansion inside an iteration will always yield the content of c as it was prior to the iteration. So using the # operator inside an iteration is almost always wrong.
If I correctly understand your minimal incomplete non-working example, I can only guess what you probably wanted to do, i.e. limit the plot of a dataset in a certain column which is selected by some variable. Correct? If my guess is true, I would do it the following way, no need for string conversion and the use of macros. Check help column.
a=2
# perform some basic operation like:
b=a*2
plot path1 u 1:($1<=0 ? column(b) : NaN) w filledcurves y=0
Related
I very often plot two types of results - e.g. prediction vs measurement - into a figure for a document, where the look of the corresponding lines/scatters should be match each other in different plots, but at the beginning of the writing/plotting the final look is not decided. I would like to define a bunch of plot options for every such curve, to make it possible to replot them very efficiently.
For example a would like to define the styles like:
s_theory = [linestyle="--", color="grey", marker=None, label="simulation"]
s_measurement = [linestyle=":", color="black", marker="s", markersize="5",label="measurement"]
I would like to apply these magically on plt.plot():
plt.plot(xt,yt,**s_theory)
plt.plot(xm,ym,**s_measurement)
How can I do that? What is the magic word I did not found during my search for this task? I am pretty sure there is a very simple to do that.
Based on the comment of ImportanceOfBeingErnest:
style_sim = {"linestyle":"--", "color":"grey", "marker":"None", "label":"simulation"}
style_meas = {"linestyle":":", "color":"black", "marker":"s", "markersize":5, "label":"measurement"}
plt.plot(xt,yt,**style_sim)
plt.plot(xm,ym,**style_meas)
If you find it useful, please vote up the comment of ImportanceOfBeingErnest!
I'm trying to do some simple fits using Gnuplot and encountering an error which somehow I'm not able to explain. Seems that I'm doing something terribly wrong with the definition of my function.
I first started with a fit of some functions. The functional form of these is not important as the fits work pretty well, but since they are involved later I'm reporting them as well.
evap(x)=(x>x_fc)?A*qnet(x)/wm2_to_mmh:(x<x_wp)?0:(A*qnet(x)/wm2_to_mmh)*(x-x_wp)/(x_fc-x_wp)
fit evap(x) './fluxes_da_1p0.txt' using 1:2 via A, x_fc, x_wp
sensible(x)=( (qnet(x)/wm2_to_mmh)-evap(x) ) / (1+B)+C
fit sensible(x) './fluxes_da_1p0.txt' using 1:3 via B,C
Then I defined
deltasensible(x)=abs(sensible(x)-sensible(0.454))
deltalatent(x)=abs(evap(x)-evap(0.454))
period_adv=18.0
g(x)=m*deltalatent(x)*period_adv*(deltasensible(x))**e
If I impose
m=3.8
e=0.5
and just plot the function g(x) superimposed on the data it seems to work pretty well.
However if I try to fit it using the parameters
fit g(x) './advection_da_1p0.txt' using 5:2 via m,e
I get the following error
iter chisq delta/lim lambda m e
0 4.2471983038e+00 0.00e+00 5.51e+00 3.800000e+00 5.000000e-01
1 3.7149813491e+00 -1.43e+04 5.51e-01 3.573384e+00 4.843345e-01
Current data point
=========================
# = 8 out of 8
x = 0.0178156
z = 0.0309726
Current set of parameters
=========================
m = 0.0178156
e = -0.0583802
"rain_estimate.gpl", line 52: Undefined value during function evaluation
For some reason Gnuplot is trying out really strange values for m,e, although I provided their initial values. If I remove the deltalatent(x) dependency everything is working fine. Am I missing something simple?
So I think I figured it out the problem by myself. Given my data a line was the best fit for Gnuplot so that it was trying to remove the exponential dependency on deltasensible by choosing a really small coefficient. Seems more an "error" with the data than with Gnuplot itself.
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
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)
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'.