Setting density to invalid values does not return correct error message in language interfaces using Clib #1412
Description
Problem description
Setting density to a negative value in a language interface using Clib does not return the correct error message. Instead, it returns the latest Cantera error thrown by other methods.
Steps to reproduce
- In the Matlab interface for Cantera, comment the first three lines in
setTemperature.mandsetDensity.mso error messages are handled by Cantera not Matlab:
% if (t <= 0)
% error('The temperature must be positive.');
% end
- Using the Matlab interface for Cantera, run the following commands in Matlab command window:
a = Air
setTemperature(a, -100)
setDensity(a, -1)
Behavior
Matlab will report two errors, first for setting an invalid temperautre:
setTemperature(a, -100)
Error using ctmethods
*******************************************************************************
CanteraError thrown by Phase::setTemperature:
temperature must be positive. T = -100
*******************************************************************************
But the second error is the same message instead of setting invalid density:
setDensity(a, -1)
Error using ctmethods
*******************************************************************************
CanteraError thrown by Phase::setTemperature:
temperature must be positive. T = -100
*******************************************************************************
System information
- Cantera version: 2.6.0
- OS: Ubuntu 22.04 LTS
- Python/MATLAB/other software versions: MATLAB R2022b
Additional context
The bug is attributed to the function thermo_setDensity in clib/ct.cpp.
int thermo_setDensity(int n, double rho)
{
if (rho < 0.0) {
return -1;
}
try {
ThermoCabinet::item(n).setDensity(rho);
} catch (...) {
return handleAllExceptions(-1, ERR);
}
return 0;
}
The check for negative density at beginning is redundant since Phase::setDensity already does that:
void Phase::setDensity(const double density_)
{
assertCompressible("setDensity");
if (density_ > 0.0) {
m_dens = density_;
} else {
throw CanteraError("Phase::setDensity",
"density must be positive. density = {}", density_);
}
}
The same issue is present in thermo_setMolarDensity. After removing the negative density check, the issue is resolved.