How do you plot this program(fortran) in vector form in gnuplot?? the command:
call execute_command_line("gnuplot plotvel.txt") does not seem to work. Nothing happens
And what does using 1:2:3:4 mean?? in " plot "file.dat" using 1:2:3:4 with vectors filled head lw 3 "
call execute_command_line("gnuplot plotvel.txt")
First of all, you are making a data file plotdata.txt at the beginning of the program, while trying to plot file.dat later, so that Gnuplot cannot find the latter. After fixing this, you can attach -persist option to keep the graph on the screen as
call execute_command_line("gnuplot -persist plotvel.txt")
Otherwise the graph disappears instantly and you cannot see the picture. Also, using 1:2:3:4 means that you plot the 1st, 2nd, 3rd, and 4th columns in your data file. For vectors, the first two represent the starting point of each vector and the last two the vector to be plotted. It is also OK to just omit using 1:2:3:4 because it is the default for vectors. (In the graph below, I removed xrange and yrange to plot all the vectors.)
Related
I have a CGAL surface_mesh of triangles with some self-intersecting triangles which I'm trying to remove to create a continuous 2-manifold shell, ultimately for printing.
I've attempted to use remove_self_intersection() and autorefine_and_remove_self_intersections() from this answer. The first only removes a few self-intersections while the second completely removes my mesh.
So, I'm trying my own approach - I'm finding the self-intersections and then attempting to delete them. I've tried using the low level remove_face but the borders are not detectable afterwards so I'm unable to fill the resulting holes. This answer refers to using the higher level Euler remove_face but this method, and make_hole seem to discard my mesh entirely.
Here is an extract (I'm using break to see if I can get at least one triangle removed, and I'm just trying with the first of the pair):
vector<pair<face_descriptor, face_descriptor> > intersected_tris;
PMP::self_intersections(mesh, back_inserter(intersected_tris));
for (pair<face_descriptor, face_descriptor> &p : intersected_tris) {
CGAL::Euler::remove_face(mesh.halfedge(get<0>(p)), mesh);
break;
}
My approach to removing self-intersecting triangles is to aggressively delete the intersecting faces, along with nearby faces and fill the resulting holes. Thanks to #sloriot 's comment I realised that the Euler::remove_face function was failing due to duplicate faces in the set returned from both the self_intersections and expand_face_selection functions.
A quick way to remove duplicate faces from the vector result of those two functions is:
std::set<face_descriptor> s(selected_faces.begin(), selected_faces.end());
selected_faces.assign(s.begin(), s.end());
This code converts the vector of faces into a set (sets contain no duplicates) and then converting the set back again.
Once the duplicates were removed, the Euler::remove_face function worked correctly, including updating the borders so that the triangulate_hole function could be used on the result producing a final surface with no self-intersections.
So this question has been asked a few times, but I think my C++ skills are too deficient to really appreciate the answers. What I need is a way to start with an HEVC encoded video and end with CSV that has all the motion vectors. So far, I've compiled and run the reference decoder, everything seems to be working fine. I'm not sure if this matters, but I'm interested in the motion vectors as a convenient way to analyze motion in a video. My plan at first is to average the MVs in each frame to just get a value expressing something about the average amount of movement in that frame.
The discussion here tells me about the TComDataCU class methods I need to interact with to get the MVs and talks about how to iterate over CTUs. But I still don't really understand the following:
1) what information is returned by these MV methods and in what format? With my limited knowledge, I assume that there are going to be something like 7 values associated with the MV: the frame number, an index identifying a macroblock in that frame, the size of the macroblock, the x coordinate of the macroblock (probably the top left corner?), the y coordinate of the macroblock, the x coordinate of the vector, and the y coordinate of the vector.
2) where in the code do I need to put new statements that save the data? I thought there must be some spot in TComDataCU.cpp where I can put lines in that print the data I want to a file, but I'm confused when the values are actually determined and what they are. The variable declarations look like this:
// create motion vector fields
m_pCtuAboveLeft = NULL;
m_pCtuAboveRight = NULL;
m_pCtuAbove = NULL;
m_pCtuLeft = NULL;
But I can't make much sense of those names. AboveLeft, AboveRight, Above, and Left seem like an asymmetric mix of directions?
Any help would be great! I think I would most benefit from seeing some example code. An explanation of the variables I need to pay attention to would also be very helpful.
At TEncSlice.cpp, you can access every CTU in loop
for( UInt ctuTsAddr = startCtuTsAddr; ctuTsAddr < boundingCtuTsAddr; ++ctuTsAddr )
then you can choose exact CTU by using address of CTU.
pCtu(TComDataCU class)->getCtuRsAddr().
After that,
pCtu->getCUMvField()
will return CTU's motion vector field. You can extract MV of CTU in that object.
For example,
TComMvField->getMv(g_auiRasterToZscan[y * 16 + x])->getHor()
returns specific 4x4 block MV's Horizontal element.
You can save these data after m_pcCuEncoder->compressCtu( pCtu ) because compressCtu determines all data of CTU such as CU partition and motion estimation, etc.
I hope this information helps you and other people!
I'm trying to do edge detection with SimpleCV on a RasPi by first finding all the lines in an image and then filtering items set based on location, intersect angle and color. I have the filtering figured out, but am having difficulty displaying the image with the filtered lines drawn in.
Currently I am can draw the full line set with
handle_lin = my_lines_full.draw()
handle_img = some_image.show()
and the filtered line set independently with
handle_lin = my_lines_filtered.draw()
handle_img = some_image.show()
but since this method also displays the full line set, no difference is seen when I do them in the same script. Whats the best way to erase the layer that stores the line drawings or selectively remove elements of the drawing?
Sovled(-ish):
Seems as though the some_lines.draw() command toggles line sets so by repeating the .draw() command before updating the lines set I can clear the layer that is displayed on the image.
I have an array - 2D(100 x 100 in this case) with some states limited within borders as shown on picture:
http://tinypic.com/view.php?pic=mimiw5&s=5#.UkK8WIamiBI
Each cell has its own id(color, for example green is id=1) and flag isBorder(marked as white on pic if true). What I am trying to do is exclude set of cell with one state limited with borders(Grain) so i could work on each grain separately which means i would need to store all indexes for each grain.
Any one got an idea how to solve it?
Now that I've read your question again... The algorithm is essentially the same as filling the contiguous area with color. The most common way to do it is a BFS algorithm.
Simply start within some point you are sure lays inside the current area, then gradually move in every direction, selecting traversed fields and putting them into a vector.
// Edit: A bunch of other insights, made before I understood the question.
I can possibly imagine an algorithm working like this:
vector<2dCoord> result = data.filter(DataType::Green);
for (2dCoord in result) {
// do some operations on data[2dCoord]
}
The implementation of filter in a simple unoptimized way would be to scan the whole array and push_back matching fields to the vector.
If you shall need more complicated queries, lazily-evaluated proxy objects can work miracles:
data.filter(DataType::Green)
.filter_having_neighbours(DataType::Red)
.closest(/*first*/ 100, /*from*/ 2dCoord(x,y))
.apply([](DataField& field) {
// processing here
});
Is there a way to get the number of lines currently on a matplotlib plot? I find myself setting colors in a colormap using a counter and multiplier to step through the color values--which seems rather un-pythonic.
All the Line2D objects in an axes are stored into a list
ax.lines
If you use only simple line plots, the lenght of the above list is enough.
If you use plt.errorbar the situation is a bit more complicated, as it creates multiple Line2D objects (central lines, vertical and horizontal error bars and their caps).
If you want to automatise the colours to assign to lines you can create a cycle like this
import itertools as it
colors = it.cycle(list of colors)
and then call the next color with colors.next() and restart from the first after it gets to the last