I’m pretty new to Root, so am not sure if I’m doing something wrong, but the following code is almost entirely copied from an example and runs fine on an online C++ Shell, however has an intermittent issue with the std::accumulate line when running in Root.
What is more confusing is that the same code worked when first tried in Root, and then having changed a copy of the code, closed and re-opened the terminal, it would not run?
The error that comes up is as follows: "Function accumulate(myvector.begin(),myvector.end(),0.0) is not defined in current scope ".
Any help would be appreciated.
Thanks,
Alistair.
{
#include <iostream>
#include <vector>
#include <numeric>
std::vector<int> myvector;
for (int i=1; i<=5; i++) myvector.push_back(i);
std::cout << "myvector contains:";
for (std::vector<int>::iterator it = myvector.begin() ; it != myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';
int tot = std::accumulate(myvector.begin(),myvector.end(),0.0);
std::cout << tot << std::endl;
return 0;
}```
___
_ROOT Version: 5.34/36
_Platform: Linux 2.6
_Compiler: Terminal
___
Hi Alistair,
I think the problem is that you have #includes inside the body of your function. More issues might be due to your ROOT version (please switch to v6 if possible, v5 has not been actively developed in years).
Thanks for the reply; I’ll try that, but I had a much longer function (not attached as it’s way too long) with the #includes outside and that still didn’t work?
I’ll try switching, but that may be difficult as I’m on a shared system - Any chance of a workaround for version 5?
Sure; I tried that this morning first thing and it still didn’t like it; first of all I got the “Note: File “iostream” already loaded” warning, which stopped the macro, and when deleting this line, the first time the macro runs with no errors, but no output either, the second time it repeats the same note for “vector”, and then “numeric”.
When I comment out all of the “#includes” it then starts displaying the original “Function accumulate is not defined” error!
This is the exact code I have in the macro; I realised I’d left “return 0;” in there from the original C++ example, but deleting this doesn’t change anything!
/*
#include <iostream>
#include <vector>
#include <numeric>
*/
{
std::vector<int> myvector;
for (int i=1; i<=5; i++) myvector.push_back(i);
std::cout << "myvector contains:";
for (std::vector<int>::iterator it = myvector.begin() ; it != myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';
int tot = std::accumulate(myvector.begin(),myvector.end(),0.0);
std::cout << tot << std::endl;
}
That’s the error, I’m running Scientific Linux 6.3 with GNOME 2.28.2. It’s a shared system and I’m just working out of the terminal - Is that the compiler information?
(Sorry, still very new to all of this!)
Let’s try to reduce this.
Save this code in macro.C and execute it with root -l -b -q macro.C. It should print 6.
I just tested it and it works with ROOT v6.14.
What do you get?
Code:
#include <numeric>
#include <vector>
void macro() {
std::vector<int> v{1,2,3};
int sum = std::accumulate(v.begin(), v.end(), 0);
std::cout << sum << std::endl;
return;
}
I understand that you can’t move away from ROOT v5, but please consider talking to your system administrator about it. v6 is actively being developed and has a better C++ interpreter (e.g. the macro above just works).
Cheers,
Enrico
P.S.
your compiler version is probably returned by gcc --version, unless you use clang in which it’s clang --version (it’s probably gcc ).
Alright, it’s saved, but as it’s a shared system I don’t have access to the original macro folder, so I use gROOT->SetMacroPath("[filepath]") every time I start Root. Is there a way I can execute it as you suggested while changing the file path?
According to your first post here, you are using ROOT 5.34. In this case, you MUST precompile your named macro with ACLiC (if you need “std::accumulate”, of course), e.g.: root [0] .x testfunc.cxx++
In the “Welcome to ROOT” box, it says version 5.34/38, and I’ve tried compiling it using ACLiC, but it either throws a set of errors that don’t otherwise pop up in my code (although admittedly not using std::accumulate). I’ve also tried that, but it with my current macros, but it doesn’t run. Do I need to save it as a .cxx file, as opposed to .C?
I’ve tried executing the macro as a .cxx++ and it produced the error “macro accumulatetest.cxx not found in path [filepath]”, with the correct path, and also runs up to the known error with the std::accumulate when executed as .x accumulatetest.C, hence why I was asking about the extension change!
is your compiler recent enough?)