unable to fplot with RcppOctave

[iembry-USGS]

Hi, I am attempting to follow some examples of fplot in GNU Octave with RcppOctave. Although there are errors in GNU Octave, all 3 of the plots are drawn, but none of them are drawn in R.

in R 3.2.4 (there are no plots)

library(RcppOctave)
o_source(text = "
fplot('2*sin(theta)+2', [0 2*pi]); % page 443 Brockman
fplot("[cos(x), sin(x)]", [0 2*pi])
fplot(@cos, [0, 2*pi])
")

In addition, in R, this is the error message that appears:

Error: unexpected string constant in:
" fplot(@cos, [0, 2*pi])
""

in GNU Octave 3.8.1 (although I have the errors, all 3 of the attempted plots are drawn)

octave:1> fplot('2*sin(theta)+2', [0 2*pi]); % page 443 Brockman
error: invalid value = northeast
error: set: invalid value for radio property "location" (value = northeast)
error: called from:
error:   /usr/share/octave/3.8.1/m/plot/appearance/legend.m at line 995, column 11
error:   /usr/share/octave/3.8.1/m/plot/draw/fplot.m at line 176, column 7
octave:1> 
octave:1> fplot("[cos(x), sin(x)]", [0 2*pi])
error: invalid value = northeast
error: set: invalid value for radio property "location" (value = northeast)
error: called from:
error:   /usr/share/octave/3.8.1/m/plot/appearance/legend.m at line 995, column 11
error:   /usr/share/octave/3.8.1/m/plot/draw/fplot.m at line 181, column 7
octave:1> 
octave:1> fplot(@cos, [0, 2*pi])
error: invalid value = northeast
error: set: invalid value for radio property "location" (value = northeast)
error: called from:
error:   /usr/share/octave/3.8.1/m/plot/appearance/legend.m at line 995, column 11
error:   /usr/share/octave/3.8.1/m/plot/draw/fplot.m at line 176, column 7
octave:1> 

Thank you.

Irucka

[git-steb]

Hi Irucka,

With a slight correction, your code works for me without error.
First change is to use only single quotes '...' inside your script text, which itself is quoted using "..."; that removes the error.

Second change, is to add print -dpng at the end of your script. Without this, you won't see the figure.
I'm suspecting this works, because it writes a file somewhere temporarily, that RcppOctave automatically picks up and shows.

I'm using

R version 3.3.3 (2017-03-06) -- "Another Canoe"
GNU Octave, version 4.0.2
on Ubuntu 16.04

Here is a new version of your example:

library(RcppOctave)
o_source(text = "
clf;
hold on;
fplot('2*sin(theta)+2', [0 2*pi]); % page 443 Brockman
fplot('[cos(x), sin(x)]', [0 2*pi])
fplot(@cos, [0, 2*pi])
grid on
set(findobj(gca, 'Type', 'Line'), 'LineWidth', 2);
set(gca,'fontsize',14);
title('Waves');
xlabel time
ylabel something
print -dpng
")

Output:

Cheers,
Steven

PS: The RcppOctave team has done a great job with this interface!

PPS: An afterthought: Since o_source(text="close all") can be used to close the figure window, I'm not sure whether it shows up because of the temporary .png file, or whether print does something else that brings the initially hidden Octave figure window to the screen.

[renozao]

@iembry-USGS, which version of RcppOctave are you using?
I added better support for plots when fixing issue #10 (dfd3e0f and 29e5e23).
This is available from the develop branch. Please let me know if this solves your problem.

[git-steb]

I've tried version 18.03 in the development branch. After fixing a minor compilation issue in pull request #17, the package installs and plots show up without needing the print command, I used in the last line of my example above.

I'm not the original poster, but my problem with this is solved. Thanks!

[iembry-USGS]

@renozao, I'm sorry for my delayed response: RcppOctave 0.18.1. Thank you for your continued development of this package.

@git-steb, I too am sorry for my delayed response. Thank you for your suggestions. I have tried your code unsuccessfully.

I am using:

R version 3.4.0 (2017-04-21) -- "You Stupid Darkness"
RcppOctave 0.18.1 - Unsuccessfully tried to install development version (see new issue)
GNU Octave 3.8.1
Trisquel 7.0 (Ubuntu 14.04)

The R code:

library(RcppOctave)

o_source(text = "
+ clf;
+ hold on;
+ fplot('2*sin(theta)+2', [0 2*pi]); % page 443 Brockman
+ fplot('[cos(x), sin(x)]', [0 2*pi])
+ fplot(@cos, [0, 2*pi])
+ grid on
+ set(findobj(gca, 'Type', 'Line'), 'LineWidth', 2);
+ set(gca,'fontsize',14);
+ title('Waves');
+ print -dpng
+ ")

# Error below:

Error in .CallOctave("source", file) : 
  RcppOctave - error in Octave function `source`:
  invalid value = northeast
set: invalid value for radio property "location" (value = northeast)
called from:
  /usr/share/octave/3.8.1/m/plot/appearance/legend.m at line 995, column 11
  /usr/share/octave/3.8.1/m/plot/draw/fplot.m at line 176, column 7
  /tmp/RtmpAkNtud/mfile_150849a05703 at line 4, column 1

Thank you.

Irucka