I am trying some codes from ITK in Qt4 now, just as a IDE.
One interesting thing is after typedef the object cannot auto complete the possible properties.
// Declare the image
typedef itk::Image<short, 3> ImageType;
ImageType::SizeType imSize = {{256, 256, 10}};
ImageType::Pointer im = ImageType::New();
im->SetRegions(imSize);
im->Allocate();
Here im-> has the trouble. Everytime I have to fill by hand.
I guess this is not a bug?
Related
So I tried using code from another post around here to see if I could use it, it was a code meant to utilize a potentiometer to move a servo motor, but when I attempted to compile it is gave the error above saying No operator "=" matches these operands in "Servo_Project.cpp". How do I go about fixing this error?
Just in case ill say this, the boards I was trying to compile the code were a NUCLEO-L476RG, the board from the post I mentioned utilized Nucleo L496ZG board and a Tower Pro Micro Servo 9G.
#include "mbed.h"
#include "Servo.h"
Servo myservo(D6);
AnalogOut MyPot(A0);
int main() {
float PotReading;
PotReading = MyPot.read();
while(1) {
for(int i=0; i<100; i++) {
myservo = (i/100);
wait(0.01);
}
}
}
This line:
myservo = (i/100);
Is wrong in a couple of ways. First, i/100 will always be zero - integer division truncates in C++. Second, there's not an = operator that allows an integer value to be assigned to a Servo object. YOu need to invoke some kind of Servo method instead, likely write().
myservo.write(SOMETHING);
The SOMETHING should be the position or speed of the servo you're trying to get working. See the Servo class reference for an explanation. Your code tries to use fractions from 0-1 and thatvisn't going to work - the Servo wants a position/speed between 0 and 180.
You should look in the Servo.h header to see what member functions and operators are implemented.
Assuming what you are using is this, it does have:
Servo& operator= (float percent);
Although note that the parameter is float and you are passing an int (the parameter is also in the range 0.0 to 1.0 - so not "percent" as its name suggests - so be wary, both the documentation and the naming are poor). You should have:
myservo = i/100.0f;
However, even though i / 100 would produce zero for all i in the loop, that does not explain the error, since an implicit cast should be possible - even if clearly undesirable. You should look in the actual header you are using to see if the operator= is declared - possibly you have the wrong file or a different version or just an entirely different implementation that happens to use teh same name.
I also notice that if you look in the header, there is no documentation mark-up for this function and the Servo& operator= (Servo& rhs); member is not documented at all - hence the confusing automatically generated "Shorthand for the write and read functions." on the Servo doc page when the function shown is only one of those things. It is possible it has been removed from your version.
Given that the documentation is incomplete and that the operator= looks like an after thought, the simplest solution is to use the read() / write() members directly in any case. Or implement your own Servo class - it appears to be only a thin wrapper/facade of the PwmOut class in any case. Since that is actually part of mbed rather than user contributed code of unknown quality, you may be on firmer ground.
I'm trying to do the aggregate insertion of x-monotone polylines, but I get the following error:
terminate called after throwing an instance of 'CGAL::Precondition_exception'
what(): CGAL ERROR: precondition violation!
Expr: i != INVALID_INDEX
File: /home/vladimir/lib-cgal/include/CGAL/Arr_polycurve_basic_traits_2.h
Line: 727
And have no clue why it happens. Do I miss something? Is my input wrong? Or is it a bug? Here is a code snippet resulting in this behavior:
#include <vector>
#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
#include <CGAL/Arr_segment_traits_2.h>
#include <CGAL/Arr_polyline_traits_2.h>
#include <CGAL/Arrangement_2.h>
typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;
typedef Kernel::Point_2 Point_2;
typedef CGAL::Arr_segment_traits_2<Kernel> Segment_traits_2;
typedef CGAL::Arr_polyline_traits_2<Segment_traits_2> Geom_traits_2;
typedef CGAL::Arrangement_2<Geom_traits_2> Arrangement_2;
int main()
{
Arrangement_2 arr;
std::vector<Geom_traits_2::X_monotone_curve_2> segments;
{
auto ctor = arr.geometry_traits()->construct_x_monotone_curve_2_object();
typedef std::vector<Point_2> Line;
std::vector<Line> lines = {
{{0,0}, {8,0}},
{{2,0}, {7,0}},
{{4,2}, {6,3}},
{{1,1}, {3,0}, {5,0}},
};
for (auto &line: lines) {
segments.push_back(ctor(line.begin(), line.end()));
}
}
insert(arr, segments.begin(), segments.end());
return 0;
}
CGAL version I'm using is 4.7, but I have tried it with 4.5.2 and the lates git version (81d638341) with the same result.
The lines are intersecting, but that should be fine as I understand. I have observed that changing {{1,1}, {3,0}, {5,0}} to {{2,1}, {3,0}, {5,0}} results in no error. And splitting {{1,1}, {3,0}, {5,0}} into two segments {{1,1}, {3,0}}, {{3,0}, {5,0}} results in no error as well.
I have also noticed another thread (link) with similar problem which was fixed, but I don't see this fix in the version 4.7. Probably it's fixed somewhere else in the code, or perhaps this fix got lost somehow.? Anyway, it looks like it's not related to my problem, but one never knows.
I was able to reproduce the problem and at first glance it looks like a bug. We are looking into it, but for now you have 2 options to work around the problem:
1. Use incremental insertion. The incremental insertion is based on a completely different algorithm.
2. Break each polyline into segments and construct an arrangement of segments instead of an arrangement of polylines. I've tested it with the minimal example that produces the problem you provided (that you, by the way for that) and it works fine.
BW, the link you mentioned is unrelated.
The idea is to setup several fixed CGPoint values with macros, and read them in code flexibly (randomly or with provided integer value)
I have a header file defining several CGPoints value like this:
#define kSpawnPoint1 {550,20}
#define kSpawnPoint2 {550,80}
#define kSpawnPoint3 {200,175}
I'm generating a random integer in my code between 1 to 3, and plan to read the CGPoint value in the macro according to the integer value. But don't know how to do it. After learning other tutorials about preprocessors, I write my code like following.
#define kSpawnPoint1 {550,20}
#define kSpawnPoint2 {550,80}
#define kSpawnPoint3 {200,175}
#define kSpawnPoint(x) kSpawnPoint##x
in the m file:
int tempInt = 1;
CGPoint tempSpawnPoint = kSpawnPoint(temInt);
However it doesn't work.(with warning: undeclared identifier 'kSpawnPointspawnPoint') How can I make this right? And is it the right way to pre-define several CGPoint? I think I must use the preprocessor to achieve this considering future multi-screen resolution support would be easier to implement in macro too, and my kSpawnPoints would not be the same with different screen resolution.
Macros only operate on text, not the values of variables. When you write kSpawnPoint(an_int), the preprocessor takes the literal string "an_int" and then pastes it, so you end up with kSpawnPointan_int. Thus, you would have to put a literal number as the argument in order to end up with one of your points: kSpawnPoint(1) -> kSpawnPoint1 -> {550, 20}
To choose randomly among your macros, you will have to put them into a structure that will exist at runtime, like an array or a switch statement.
I have a simple c program for printing n Fibonacci numbers and I would like to compile it to ELF object file. Instead of setting the number of fibonacci numbers (n) directly in my c code, I would like to set them in the registers since I am simulating it for an ARM processor.How can I do that?
Here is the code snippet
#include <stdio.h>
#include <stdlib.h>
#define ITERATIONS 3
static float fib(float i) {
return (i>1) ? fib(i-1) + fib(i-2) : i;
}
int main(int argc, char **argv) {
float i;
printf("starting...\n");
for(i=0; i<ITERATIONS; i++) {
printf("fib(%f) = %f\n", i, fib(i));
}
printf("finishing...\n");
return 0;
}
I would like to set the ITERATIONS counter in my Registers rather than in the code.
Thanks in advance
The register keyword can be used to suggest to the compiler that it uses a registers for the iterator and the number of iterations:
register float i;
register int numIterations = ITERATIONS;
but that will not help much. First of all, the compiler may or may not use your suggestion. Next, values will still need to be placed on the stack for the call to fib(), and, finally, depending on what functions you call within your loop, code in the procedure are calling could save your register contents in the stack frame at procedure entry, and restore them as part of the code implementing the procedure return.
If you really need to make every instruction count, then you will need to write machine code (using an assembly language). That way, you have direct control over your register usage. Assembly language programming is not for the faint of heart. Assembly language development is several times slower than using higher level languages, your risk of inserting bugs is greater, and they are much more difficult to track down. High level languages were developed for a reason, and the C language was developed to help write Unix. The minicomputers that ran the first Unix systems were extremely slow, but the reason C was used instead of assembly was that even then, it was more important to have code that took less time to code, had fewer bugs, and was easier to debug than assembler.
If you want to try this, here are the answers to a previous question on stackoverflow about resources for ARM programming that might be helpful.
One tactic you might take is to isolate your performance-critical code into a procedure, write the procedure in C, the capture the generated assembly language representation. Then rewrite the assembler to be more efficient. Test thoroughly, and get at least one other set of eyeballs to look the resulting code over.
Good Luck!
Make ITERATIONS a variable rather than a literal constant, then you can set its value directly in your debugger/simulator's watch or locals window just before the loop executes.
Alternatively as it appears you have stdio support, why not just accept the value via console input?
I'm writing a program that updates flash memory. While I'm erasing/writing flash I would like to be executing from RAM. Ideally I'd link my code to an execution region that's stored in flash that on startup I would copy to the RAM location to which it is linked.
I don't include any of the normal generated C/C++ initialization code so I can't just tag my function as __ram.
If I could do the above then the debuggers symbols would be relevant for the copied to RAM code and I'd be able to debug business as usual.
I'm thinking that something along the lines of OVERLAY/RELOC might help but I'm not sure.
Thanks,
Maybe your application code can do it manually. Something like
pSourceAddr = &FunctionInFlash;
pDestAddr = &RamReservedForFunction;
while(pSourceAddr <= (&FunctionInFlash+FunctionSize))
{ *pDestAddr++ = *pSourceAddr++;
};
typedef int (*RamFuncPtr)(int arg1); //or whatever the signature is..
result = ((RamFuncPtr)&RamReservedForFunction)(argument1);
You should be able to get the linker definition file to export symbols for the FunctionInFlash and RamReservedForFunction addresses.