[Octave-bug-tracker] [bug #34567] Ridges in smooth plot

[anonymous]

Follow-up Comment #2, bug #34567 (project octave):

"octave:7> [x,y] = meshgrid(-2*pi:.2:2*pi);
octave:8> z = e**(x).*cos(y);
octave:9> surf(x,y,z)
octave:10> print -dpng bad_figure.png"

I noticed when I looked at the code again that I forgot to use elemental
exponentiation for the e^x term. The correct plot looked nice. 

I don't know enough about how these are supposed to work to know if the graph
I accidentally produced is right or not, so the ridges are probably just the
result of some operation I don't understand. I'm sorry about that if it turns
out to be a goose chase.

I still observed the bug with certain tiles on the surface being transparent
to some degree. I attached two examples of this:

"octave:12> [x,y] = meshgrid(-2*pi:1:2*pi);
octave:13> z=e.**(x).*cos(y)
octave:14> surf(x,y,z)
octave:15> z=e**(x).*cos(y)
octave:16> surf(x,y,z)
octave:17> view 
Display all 2138 possibilities? (y or n)
octave:17> help view
`view' is a function from the file /usr/share/octave/3.2.4/m/plot/view.m

 -- Function File:  view (AZIMUTH, ELEVATION)
 -- Function File:  view (DIMS)
 -- Function File: [AZIMUTH, ELEVATION] = view ()
     Set or get the viewpoint for the current axes.


Additional help for built-in functions and operators is
available in the on-line version of the manual.  Use the command
`doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at http://www.octave.org and via the address@hidden
mailing list.
octave:18> view(50)
error: view: expecting single argument to be 2 or 3
error: called from:
error:   /usr/share/octave/3.2.4/m/plot/view.m at line 43, column 2
octave:18> view(50,25)
octave:19> view(40,25)
octave:20> view(30,25)
octave:21> view(20,25)
octave:22> view(-5,25)
octave:23> hold on; print -dpng bad_figure2.png
octave:24> view(53,160)

gnuplot> set view -70, 53;
                         ^
         line 0: rot_x must be in [0:180] degrees range; view unchanged

octave:25> view(160,53)
octave:26> view(160,54)
octave:27> hold on; print -dpng bad_figure3.png"


(file #24160, file #24161, file #24162)
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Additional Item Attachment:

File name: bad_figure.png                 Size:283 KB
File name: bad_figure2.png                Size:125 KB
File name: bad_figure3.png                Size:160 KB


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