I want to determine that two vehicles are getting far away. I wrote my codes in handlepositionupdate method of TraCIDemo11p class but only half of my code runs correctly.
Coord senderPosition = mobility->getCurrentPosition();
double direction1=mobility->getAngleRad();
std::map<std::string, cModule*> availableCars = mobility->getManager()-
>getManagedHosts();
std::map<std::string, cModule*>::iterator it;
for(it = availableCars.begin(); it != availableCars.end(); it++)
{
TraCIMobility* mobility2 = TraCIMobilityAccess().get(it->second);
double direction2=mobility2->getAngleRad();
Coord receiverPosition = mobility2->getCurrentPosition();
if(direction2!=direction1){
std::cout<<"they move in opposite direction"<<endl;
}
double distance1=senderPosition.distance(receiverPosition);
WaveShortMessage* wsm = new WaveShortMessage();
scheduleAt(simTime()+1,wsm);
cArray array("array1");
int index = array.add(wsm);
double distance2=senderPosition.distance(receiverPosition);
if(distance2>distance1){
std::cout<<"they are getting far away"<<endl;
array.remove(index);
array.addAt(index, bsm);
}
}
}
when I run it ,it just presents they move in opposite direction and The rest of it is not presented.
therefore I want that my code determines which vehicles are getting far away.where is my problem?
I really appreciate any help.
I understood where is my mistake.
I calculate distance1 and distance2 at same time. However I should calculate them in different time.
for this purpose I consider getpositionAt() method instead of getcurrentposition().
simtime_t T=simTime()+60;
senderposition1=mobility->getpositionAt(T);
receiverposition1=mobility2->getpositionAt(T);
double distance2=senderposition1.Distance(receiverposition1);
Related
I have a vector holding 10 items (all of the same class for simplicity call it 'a'). What I want to do is to check that 'A' isn't either a) hiding the walls or b) hiding another 'A'. I have a collisions function that does this.
The idea is simply to have this looping class go though and move 'A' to the next position, if that potion is causing a collision then it needs to give itself a new random position on the screen. Because the screen is small, there is a good chance that the element will be put onto of another one (or on top of the wall etc). The logic of the code works well in my head - but debugging the code the object just gets stuck in the loop, and stay in the same position. 'A' is supposed to move about the screen, but it stays still!
When I comment out the Do while loop, and move the 'MoveObject()' Function up the code works perfectly the 'A's are moving about the screen. It is just when I try and add the extra functionality to it is when it doesn't work.
void Board::Loop(void){
//Display the postion of that Element.
for (unsigned int i = 0; i <= 10; ++i){
do {
if (checkCollisions(i)==true){
moveObject(i);
}
else{
objects[i]->ResetPostion();
}
}
while (checkCollisions(i) == false);
objects[i]->SetPosition(objects[i]->getXDir(),objects[i]->getYDir());
}
}
The class below is the collision detection. This I will expand later.
bool Board::checkCollisions(int index){
char boundry = map[objects[index]->getXDir()][objects[index]->getYDir()];
//There has been no collisions - therefore don't change anything
if(boundry == SYMBOL_EMPTY){
return false;
}
else{
return true;
}
}
Any help would be much appreciated. I will buy you a virtual beer :-)
Thanks
Edit:
ResetPostion -> this will give the element A a random position on the screen
moveObject -> this will look at the direction of the object and adjust the x and Y cord's appropriately.
I guess you need: do { ...
... } while (checkCollisions(i));
Also, if you have 10 elements, then i = 0; i < 10; i++
And btw. don't write if (something == true), simply if (something) or if (!something)
for (unsigned int i = 0; i <= 10; ++i){
is wrong because that's a loop for eleven items, use
for (unsigned int i = 0; i < 10; ++i){
instead.
You don't define what 'doesn't work' means, so that's all the help I can give for now.
There seems to be a lot of confusion here over basic language structure and logic flow. Writing a few very simple test apps that exercise different language features will probably help you a lot. (So will a step-thru debugger, if you have one)
do/while() is a fairly advanced feature that some people spend whole careers never using, see: do...while vs while
I recommend getting a solid foundation with while and if/else before even using for. Your first look at do should be when you've just finished a while or for loop and realize you could save a mountain of duplicate initialization code if you just changed the order of execution a bit. (Personally I don't even use do for that any more, I just use an iterator with while(true)/break since it lets me pre and post code all within a single loop)
I think this simplifies what you're trying to accomplish:
void Board::Loop(void) {
//Display the postion of that Element.
for (unsigned int i = 0; i < 10; ++i) {
while(IsGoingToCollide(i)) //check is first, do while doesn't make sense
objects[i]->ResetPosition();
moveObject(i); //same as ->SetPosition(XDir, YDir)?
//either explain difference or remove one or the other
}
}
This function name seems ambiguous to me:
bool Board::checkCollisions(int index) {
I'd recommend changing it to:
// returns true if moving to next position (based on inertia) will
// cause overlap with any other object's or structure's current location
bool Board::IsGoingToCollide(int index) {
In contrast checkCollisions() could also mean:
// returns true if there is no overlap between this object's
// current location and any other object's or structure's current location
bool Board::DidntCollide(int index) {
Final note: Double check that ->ResetPosition() puts things inside the boundaries.
I have a working solution for this, though I am convinced there must be a better implementation. In a nut shell the problem is this:
I am working on a connect>=3, bejewelled style puzzle game. When the state of the 'board' changes I group all the pieces such that if they are 'connected' horizontally or vertically they share an ID. This is how I do it currently:
[pseudo]
for all( array object* )
{
if !in_a_group() check_neighbours( this )
}
void check_neighbours( ID )
{
if ( check_is_same_type( left ) )
{
if !in_a_group() this.ID = ID ; check_neighbours( ID )
else if( in_a_group ) change_IDs(this.ID, ID )
}
same for right ...
up ...
down ...
}
That is a really dirty pseudo version of what I do.
I recursively call check_neighbours, passing the ID of the first branch piece forward (I use this pointer as an ID rather than generating one).
If I find a piece with a different ID that is connected I overwrite all pieces with that ID with new ID ( I have an ASSERT here cos it shouldn't actually happen. It hasn't so far in lots of testing)
I don't check_neighbours at the original branch unless the piece has no ID.
This works just fine, though my pseudo is probably missing some small logic.
My problem is that it has the potential to use many branches (which may be a problem on the hardware I am working on). I have worked on the problem so long now that I can't see another solution. Ever get the feeling you are missing something incredibly obvious?
Also I am new to stackoverflow, reasonably new to programming and any advice on etiquette etc is appreciated.
How would you suggest avoiding recursion?
As I understand it, your algorithm is basically a "flood fill" with a small twist.
Anyway, to avoid recursion, you need to allocate array to store coordinates of unprocessed items and use queue or fifo. Because you know dimensions of grid (and since it is bejeweled-style(?) game, you should be able to preallocate it pretty much anywhere.
pseudocode for any flood-fill-type recursive algorithm.
struct Coord{
int x, y;
}
typedef std::queue<Coord> CoordQueue;
bool validCoord(Coord coord){
return (coord.x >= 0) && (coord.y >= 0)
&& (coord.x < boardSizeX) && (coord.y < boardSizeY);
}
bool mustProcessCoord(Coord coord);
void processAll(){
CoordQueue coordQueue;
Coord startPoint = Coord(0, 0);
coordQueue.pushBack(startPoint);
while (!coordQueue.empty()){
const Coord &curCoord = coordQueue.front();
//do something with current coordinates.
processCoord(curCoord);
const int numOffsets = 4;
const int offsets[numOffsets][2] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
for (int offsetIndex = 0; offsetIndex < numOffsets; offsetIndex++){
Coord neighborCoord = Coord(curCoord.x + offsets[offsetIndex][0],
curCoord.y + offsets[offsetIndex][1]);
if (!isValidCoord(neighborCoord) || !mustProcessCoord(neighborCoord))
continue;
coordQueue.push_back(neighborCoord);
}
coordQueue.pop_front();
}
}
See ? no recursion, just a loop. Pretty much any recursive function can be unwrapped into something like that.
If your underlying platform is restrictive and you have no std::queue, use array (ring buffer implemented as array can act like fifo queue) instead. Because you know size of the board, you can precalculate size of array. The rest should be easy.
Okay, I have been set with the task of comparing this list of Photons using one method (IU) and comparing it with another (TSP). I need to take the first IU photon and compare distances with all of the TSP photons, find the smallest distance, and "pair" them (i.e. set them both in arrays with the same index). Then, I need to take the next photon in the IU list, and compare it to all of the TSP photons, minus the one that was chosen already.
I know I need to use a Boolean array of sorts, with keeping a counter. I can't seem to logic it out entirely.
The code below is NOT standard C++ syntax, as it is written to interact with ROOT (CERN data analysis software).
If you have any questions with the syntax to better understand the code, please ask. I'll happily answer.
I have the arrays and variables declared already. The types that you see are called EEmcParticleCandidate and that's a type that reads from a tree of information, and I have a whole set of classes and headers that tell that how to behave.
Thanks.
Bool_t used[2];
if (num[0]==2 && num[1]==2) {
TIter photonIterIU(mPhotonArray[0]);
while(IU_photon=(EEmcParticleCandidate_t*)photonIterIU.Next()){
if (IU_photon->E > thresh2) {
distMin=1000.0;
index = 0;
IU_PhotonArray[index] = IU_photon;
TIter photonIterTSP(mPhotonArray[1]);
while(TSP_photon=(EEmcParticleCandidate_t*)photonIterTSP.Next()) {
if (TSP_photon->E > thresh2) {
Float_t Xpos_IU = IU_photon->position.fX;
Float_t Ypos_IU = IU_photon->position.fY;
Float_t Xpos_TSP = TSP_photon->position.fX;
Float_t Ypos_TSP = TSP_photon->position.fY;
distance_1 = find distance //formula didnt fit here //
if (distance_1 < distMin){
distMin = distance_1;;
for (Int_t i=0;i<2;i++){
used[i] = false;
} //for
used[index] = true;
TSP_PhotonArray[index] = TSP_photon;
index++;
} //if
} //if thresh
} // while TSP
} //if thresh
} // while IU
Thats all I have at the moment... work in progress, I realize all of the braces aren't closed. This is just a simple logic question.
This may take a few iterations.
As a particle physicist, you should understand the importance of breaking things down into their component parts. Let's start with iterating over all TSP photons. It looks as if the relevant code is here:
TIter photonIterTSP(mPhotonArray[1]);
while(TSP_photon=(EEmcParticleCandidate_t*)photonIterTSP.Next()) {
...
if(a certain condition is met)
TSP_PhotonArray[index] = TSP_photon;
}
So TSP_photon is a pointer, you will be copying it into the array TSP_PhotonArray (if the energy of the photon exceeds a fixed threshold), and you go to a lot of trouble keeping track of which pointers have already been so copied. There is a better way, but for now let's just consider the problem of finding the best match:
distMin=1000.0;
while(TSP_photon= ... ) {
distance_1 = compute_distance_somehow();
if (distance_1 < distMin) {
distMin = distance_1;
TSP_PhotonArray[index] = TSP_photon; // <-- BAD
index++; // <-- VERY BAD
}
}
This is wrong. Suppose you find a TSP_photon with the smallest distance yet seen. You haven't yet checked all TSP photons, so this might not be the best, but you store the pointer anyway, and increment the index. Then if you find another match that's even better, you'll store that one too. Conceptually, it should be something like this:
distMin=1000.0;
best_photon_yet = NULL;
while(TSP_photon= ... ) {
distance_1 = compute_distance_somehow();
if (distance_1 < distMin) {
distMin = distance_1;
best_pointer_yet = TSP_photon;
}
}
// We've now finished searching the whole list of TSP photons.
TSP_PhotonArray[index] = best_photon_yet;
index++;
Post a comment to this answer, telling me if this makes sense; if so, we can proceed, if not, I'll try to clarify.
I've written my own code to parse an .obj model file - essentially just ASCII text. The file gets parsed and stored in the class correctly according to my tests. I can read back the values (from data members) just fine in the loading function.
The problem occurs when I try to read back the values in my main rendering loop. There is an access violation error on the line beginning "int v":
for(int i = 0; i<data.numFaces; i++){
for(int j = 0; j<3; j++){ //Assuming triangles for now.
int v = data.faceList[i].vertex[j]; // Access violation here.
double vX = data.vertexList[v].x;
double vY = data.vertexList[v].y;
double vZ = data.vertexList[v].z;
glVertex3d(vX, vY, vZ);
}
}
I'm not exactly sure why this happens, and I've checked everything I could possibly think of. I'm not very experienced in C++. Most of my programming experience is in Java, Python and PHP although I have previously written a medium sized project in C++.
I'm sure the problem is something basic related to memory allocation or pointers used for the dynamic arrays.
Here are the relevant parts of code in the obj loading class:
ObjData ObjLoader::LoadObj(std::string filename){
//... Initalization ...
// 1st pass: find number of elements so array sizes can be defined.
while(!file.eof()){
//...
}
//...close file...
_data.faceList = new ObjFace[_data.numFaces];
_data.vertexList = new ObjVert[_data.numVertices];
_data.uvList = new ObjUV[_data.numUVcoords];
_data.normalList = new ObjNormal[_data.numNormals];
//TODO: Make size dynamic according to each face. Just use the first 3 points for now.
for (int i = 0; i < _data.numFaces; i++){
_data.faceList[i].vertex = new int[3];
_data.faceList[i].normal = new int[3];
_data.faceList[i].uv = new int[3];
}
//... file stuff ...
// 2nd pass: read values into arrays.
while(!file.eof()){
//...
if(type=="v"){
_data.vertexList[currentVertex].x = atof(param1.c_str());
_data.vertexList[currentVertex].y = atof(param2.c_str());
_data.vertexList[currentVertex].z = atof(param3.c_str());
currentVertex++;
}else if(type=="vt"){
_data.uvList[currentUV].u = atof(param1.c_str());
_data.uvList[currentUV].v = atof(param2.c_str());
currentUV++;
}else if(type=="vn"){
_data.normalList[currentNormal].x = atof(param1.c_str());
_data.normalList[currentNormal].y = atof(param2.c_str());
_data.normalList[currentNormal].z = atof(param3.c_str());
currentNormal++;
}else if(type=="f"){
//...Within loop over each vertex in a single face ...
if(endPos != string::npos){
// Value before 1st "/" (Vertex index).
// ...find value in string...
_data.faceList[currentFace].vertex[i] = atoi(token.c_str()) -1; // File format begins indices from 1.
// Value between slashes (UV index).
// ...find value in string...
_data.faceList[currentFace].uv[i] = atoi(token.c_str()) -1;
// Value after 2nd "/" (Normal index).
// ...find value in string...
_data.faceList[currentFace].normal[i] = atoi(token.c_str()) -1;
}
//...End of loop over every vertex in a single face...
currentFace++;
}
}
return _data;
}
And the structs ObjFace, ObjVert, ObjUV and ObjNormal are defined as:
struct ObjVert{
float x, y, z;
};
struct ObjUV{
float u, v;
};
struct ObjNormal{
float x, y, z;
};
// Contains indexes.
struct ObjFace{
int* vertex;
int* uv;
int* normal;
};
Thanks for any help. Also, any good sources on avoiding these types of errors in future would be appreciated.
I had typed up some silly response which I realized wasn't right...but I had to keep thinking on it, and I came up with another idea.
Where is this object being assigned?
Your code isn't clear if data and _data are the same object or not, but I noticed that your method there seems to return _data as an object. I'm led to believe that perhaps you are using an assignment like ObjData data = LoadObj("myfilename"); somewhere?
If this is the case, I believe your problem may come from a lack of a copy constructor or overloaded assignment operator for your ObjData class. (I'm not a C++ guru, so I don't recall exactly which one this would fall under. Hopefully someone else can confirm if we're on the right track).
If your pointers are not being copied correctly during the copy and assignment (returning from LoadObj calls a copy constructor iirc, and then the obvious assignment to data), then even though you intended to already have an array of int at that location, you may in fact be accessing uninitialized memory, thus causing your Access Violation.
I'm not an expert with either copy constructors or overloaded assignment operators, but a quick way around this would be to return a pointer to an ObjData rather than to return an object itself.
At first glance I didn't see anything blatantly wrong. But if as you say it is exploding at int v = data.faceList[i].vertex[j]; then it seems very likely that the problem is either i or j or both are too big or too small.
Aside from the obvious approach of getting cozy with your debugger and flattening this bug out, the best approach to solving problems like these is probably to avoid them altogether. Certain things programmers do are more prone to errors than others. The list is long, but you do at least two of them, in spades, in your code.
1) You use dynamically-allocated arrays
2) You use hand-crafted loops
Try to avoid doing these things by using the tools that C++ gives you. Start with #1, and get rid of the dynamically-allocated arrays.
You have a struct:
struct ObjFace{
int* vertex;
int* uv;
int* normal;
};
...with 3 pointers-to-arrays-of-int. Instead of doing that, use a vector:
struct ObjFace{
vector<int> vertex;
vector<int> uv;
vector<int> normal;
};
...and then a whole lot of code you had to write before becomes much simpler now, and much less prone to mistakes:
// all this goes away
//_data.faceList = new ObjFace[_data.numFaces];
//_data.vertexList = new ObjVert[_data.numVertices];
//_data.uvList = new ObjUV[_data.numUVcoords];
//_data.normalList = new ObjNormal[_data.numNormals];
...and:
// now you ask the vector how many elements it really has
for(int i = 0; i<data.faceList.size(); i++){
for(int j = 0; j<data.faceList.size(); j++){ //Ask the vector instead of assuming triangles
int v = data.faceList[i].vertex[j]; // Access violation here.
double vX = data.vertexList[v].x;
double vY = data.vertexList[v].y;
double vZ = data.vertexList[v].z;
glVertex3d(vX, vY, vZ);
}
}
Now, look at that loop. Loops are a very common source of errors. The best loop is the loop you never have to write. So use the STL's algorithms instead. Add a function to ObjFace to execute glVertex3d on each of it's elements:
struct ObjFace{
//...
void do_vertex() const
{
typedef vector<int> ints;
for( ints::iterator it = vertex.begin(); it != vertex.end(); ++it )
glVertex3d(it->x, it->y, it->z);
}
};
...then go back and whittle down that original loop:
(psudocode, actual syntax is more complex)
typedef vector<ObjFace> ObjFaces;
for( ObjFaces::iterator it = data.faceList.begin(); it != data.faceList.end(); ++it )
it->do_vertex();
...or, with a little more effort:
for_each( data.faceList.begin(), data.faceList.end(), &ObjFace::do_vertex );
I am thinking of using wxMathPlot for plotting/graphing some data that arrives continuously. I want to draw "Real-time" plot/graph using it. Is that possible?
I.E. I don't want just a static graph of a one-time read of a file - I want the streaming data plotted and continued out to the right of the graph - (and let the left side fall off/scroll out of view)
EDIT
I still have not gotten an answer for this. There is an interesting class in the wxmathPlot library called mpFXYVector but that appears just to draw one plot from a vector of data. What I want is something that can be fed a stream and scroll the graph horizontally (and also resize the scale if needed)
Thanks ravenspoint...!! I did what you said.. It works flawless!
here is my AddData() function:
void mpFXYVector::AddData(float x, float y, std::vector<double> &xs, std::vector<double> &ys)
{
// Check if the data vectora are of the same size
if (xs.size() != ys.size()) {
wxLogError(_("wxMathPlot error: X and Y vector are not of the same length!"));
return;
}
//Delete first point if you need a filo buffer (i dont need it)
//xs.erase(xs.begin());
//xy.erase(xy.begin());
//Add new Data points at the end
xs.push_back(x);
ys.push_back(y);
// Copy the data:
m_xs = xs;
m_ys = ys;
// Update internal variables for the bounding box.
if (xs.size()>0)
{
m_minX = xs[0];
m_maxX = xs[0];
m_minY = ys[0];
m_maxY = ys[0];
std::vector<double>::const_iterator it;
for (it=xs.begin();it!=xs.end();it++)
{
if (*it<m_minX) m_minX=*it;
if (*it>m_maxX) m_maxX=*it;
}
for (it=ys.begin();it!=ys.end();it++)
{
if (*it<m_minY) m_minY=*it;
if (*it>m_maxY) m_maxY=*it;
}
m_minX-=0.5f;
m_minY-=0.5f;
m_maxX+=0.5f;
m_maxY+=0.5f;
}
else
{
m_minX = -1;
m_maxX = 1;
m_minY = -1;
m_maxY = 1;
}
}
in the Main() you only have to:
m_Vector->AddData(xPos,yPos,vectorX, vectorY);
m_plot->Fit();
I think mpFXYVector is the way to go.
The simplest way to deal with this might be to write a wrapper class for mpFXYVector which holds a FIFO buffer of recent data points. Each time a new datapoint arrives, add it to the FIFO buffer, which will drop the oldest point, then load mpFXYVector with the updated buffer. The wxMathPlot class mpWindow will look after the rest of what you need.
A more elegant approach would be a specialization of mpFXYVector which implements the FIFO buffer, using the simple vectors in mpFXYVector. The advantage of this would be that you are holding just one copy of the display data. Unless you are displaying many thousands of points, I doubt the advantage is worth the extra trouble of inheriting from mpFXYVector, rather than simply using the mpFXYVector documented interface.
After looking at the details, the only tricky bit is to replace mpFXYVector::SetData() with a new method Add() to add data points as they arrive. The new method needs to manage the mpFXYVector vectors as FIFO buffers, and to re-implement the code to update the bounding box ( which unfortunately was not written with inheritance in mind ).
The result is that specialization gives a solution with a smaller memory requirement and more flexibility than using a wrapper.
I know this is an old thread but I needed to plot a scrolling X axis with wxMathPlot.
I've done a simple modification to jayjo's code to make X axis scrolling work.
I hoe this helps.
void mpFXYVector::AddData(float x, float y, std::vector<double> &xs, std::vector<double> &ys)
{
// Check if the data vectora are of the same size
if (xs.size() != ys.size()) {
wxLogError(_("wxMathPlot error: X and Y vector are not of the same length!"));
return;
}
//After a certain number of points implement a FIFO buffer
//As plotting too many points can cause missing data
if (x > 300)
{
xs.erase(xs.begin());
ys.erase(ys.begin());
}
//Add new Data points at the end
xs.push_back(x);
ys.push_back(y);
// Copy the data:
m_xs = xs;
m_ys = ys;
// Update internal variables for the bounding box.
if (xs.size()>0)
{
m_minX = xs[0];
m_maxX = xs[0];
m_minY = ys[0];
m_maxY = ys[0];
std::vector<double>::const_iterator it;
for (it=xs.begin();it!=xs.end();it++)
{
if (*it<m_minX) m_minX=*it;
if (*it>m_maxX) m_maxX=*it;
}
for (it=ys.begin();it!=ys.end();it++)
{
if (*it<m_minY) m_minY=*it;
if (*it>m_maxY) m_maxY=*it;
}
m_minX-=0.5f;
m_minY-=0.5f;
m_maxX+=0.5f;
m_maxY+=0.5f;
}
else
{
m_minX = -1;
m_maxX = 1;
m_minY = -1;
m_maxY = 1;
}
}
I do not have any personal experience with wxMathPlot, but I have been working with wxWidgets for years and highly recommend it for cross platform gui programming in c++, with that said according to the wxWiki graphics page the Numerix Graphics Library can be used for real time data so maybe that can help you out. Good luck.
Maybe someone will have same problem and will need it... I needed very fast plotting for showing the data from oscilloscope.
I was getting the data in packets. I made few changes that made a code a lot of faster.
First thing is to change the if state in function SetData from if (xs.size()>0) to if (!xs.empty).
Then you should firstly add all of your data packet to the vector
Vector1_X.push_back(x);
Vector1_Y.push_back(y);
And after that you should fit and set data.
Vector1 ->SetData(Vector1_X,Vector1_Y); // add vectors to main vector
MathPlot1-> Fit(); //fit plot to the data
Vector1_X.clear(); //if you want to clear plot after every packet
Vector1_Y.clear(); //you should use it
Your code in main function will be longer but function will be faster because you add all data "at once".
We ended up using ChartDirector instead. It has a lot of capability and is fast.