Describe the bug
ADIOS2 seems to fundamentally support variables that change their shape across steps. This includes changes in dimensionality:
> bpls sample.bp5/ -dt
Step 0:
int32_t /data/meshes/theta {5}
(0) 0 1 2 3 4
Step 1:
int32_t /data/meshes/theta {10}
(0) 0 1 2 3 4 5
(6) 6 7 8 9
Step 2:
int32_t /data/meshes/theta {2, 5}
(0,0) 0 1 2 3 4 5
(1,1) 6 7 8 9
This dataset can be read with adios2::Mode::Read, but not adios2::Mode::ReadRandomAccess:
To Reproduce
#include <adios2.h>
#include <numeric>
static void create_file()
{
adios2::ADIOS adios;
auto IO = adios.DeclareIO("IO");
IO.SetEngine("bp5");
auto engine = IO.Open("sample.bp5", adios2::Mode::Write);
auto variable = IO.DefineVariable<int>("/data/meshes/theta", {5}, {0}, {5});
std::vector<int> data(10);
std::iota(data.begin(), data.end(), 0);
engine.BeginStep();
engine.Put(variable, data.data());
engine.EndStep();
engine.BeginStep();
variable.SetShape({10});
variable.SetSelection({{0}, {10}});
engine.Put(variable, data.data());
engine.EndStep();
engine.BeginStep();
variable.SetShape({2, 5});
variable.SetSelection({{0, 0}, {2, 5}});
engine.Put(variable, data.data());
engine.EndStep();
engine.Close();
}
static void read_file()
{
adios2::ADIOS adios;
auto IO = adios.DeclareIO("IO");
auto engine = IO.Open("sample.bp5", adios2::Mode::ReadRandomAccess);
auto variable = IO.InquireVariable<int>("/data/meshes/theta");
auto print_shape = [&](std::string const &comment) {
auto shape = variable.Shape();
std::cout << comment << ":\t";
if (shape.size() == 0)
{
std::cout << "[]\n";
}
else
{
auto it = shape.begin();
std::cout << "[" << *it++;
for (; it != shape.end(); ++it)
{
std::cout << ", " << *it;
}
std::cout << "]\n";
}
};
std::vector<int> data(10);
print_shape("After opening file");
variable.SetStepSelection({0, 1});
print_shape("Step 0");
variable.SetSelection({{0}, {5}});
variable.SetStepSelection({1, 1});
print_shape("Step 1");
variable.SetSelection({{0}, {10}});
variable.SetStepSelection({2, 1});
print_shape("Step 2");
variable.SetSelection({{0, 0}, {2, 5}});
engine.Close();
}
int main(int argsc, char **argsv)
{
create_file();
read_file();
}Produces the file printed at the top. When executed:
> ./main
After opening file: [5]
Step 0: [5]
Step 1: [10]
Step 2: [2, 5]
terminate called after throwing an instance of 'std::invalid_argument'
what(): [Tue Mar 11 14:54:44 2025] [ADIOS2 EXCEPTION] <Core> <VariableBase> <SetSelection> : count and start must be the same size as shape for variable /data/meshes/theta, in call to SetSelection
Aborted (core dumped)
The error is thrown from this line:
|
helper::Throw<std::invalid_argument>("Core", "VariableBase", "SetSelection", |
While
variable.Shape() in the reproducer correctly produces the current extent
[2, 5], gdb shows the internal value of
m_Shape as
[5], i.e. the shape from step 0.
Expected behavior
Either of the following:
- Varying dimensionality is not supported: In this case, the error should be clearer
- Varying dimensionality is supported: No error
Desktop (please complete the following information):
- OS/Platform: Ubuntu 24.04
- Build: gcc 13.3.0
- ADIOS2 v2.10.2 as well as current master a290f4e
Additional context
Add any other context about the problem here.
Following up
Was the issue fixed? Please report back.
Describe the bug
ADIOS2 seems to fundamentally support variables that change their shape across steps. This includes changes in dimensionality:
This dataset can be read with
adios2::Mode::Read, but notadios2::Mode::ReadRandomAccess:To Reproduce
Produces the file printed at the top. When executed:
The error is thrown from this line:
ADIOS2/source/adios2/core/VariableBase.cpp
Line 211 in a290f4e
While
variable.Shape()in the reproducer correctly produces the current extent[2, 5], gdb shows the internal value ofm_Shapeas[5], i.e. the shape from step 0.Expected behavior
Either of the following:
Desktop (please complete the following information):
Additional context
Add any other context about the problem here.
Following up
Was the issue fixed? Please report back.