Fix termination reason string logic and missing Python bindings

[ZedongPeng]

Description

1. There is a logic error in the termination_reason_tToString and termination_reason_to_string functions. The case for TERMINATION_REASON_UNSPECIFIED lacks a return statement or a break, causing it to fall through to the next case, which is FEAS_POLISH_SUCCESS. These two functions appear to be duplicated code.

cuPDLPx/src/utils.cu

Lines 198 to 218 in 4ff479e

	const char *termination_reason_to_string(termination_reason_t reason)
	{
	switch (reason)
	{
	case TERMINATION_REASON_OPTIMAL:
	return "OPTIMAL";
	case TERMINATION_REASON_PRIMAL_INFEASIBLE:
	return "PRIMAL_INFEASIBLE";
	case TERMINATION_REASON_DUAL_INFEASIBLE:
	return "DUAL_INFEASIBLE";
	case TERMINATION_REASON_TIME_LIMIT:
	return "TIME_LIMIT";
	case TERMINATION_REASON_ITERATION_LIMIT:
	return "ITERATION_LIMIT";
	case TERMINATION_REASON_UNSPECIFIED:
	case TERMINATION_REASON_FEAS_POLISH_SUCCESS:
	return "FEAS_POLISH_SUCCESS";
	default:
	return "UNSPECIFIED";
	}
	}

cuPDLPx/src/cli.c

Lines 29 to 49 in 4ff479e

	const char *termination_reason_tToString(termination_reason_t reason)
	{
	switch (reason)
	{
	case TERMINATION_REASON_OPTIMAL:
	return "OPTIMAL";
	case TERMINATION_REASON_PRIMAL_INFEASIBLE:
	return "PRIMAL_INFEASIBLE";
	case TERMINATION_REASON_DUAL_INFEASIBLE:
	return "DUAL_INFEASIBLE";
	case TERMINATION_REASON_TIME_LIMIT:
	return "TIME_LIMIT";
	case TERMINATION_REASON_ITERATION_LIMIT:
	return "ITERATION_LIMIT";
	case TERMINATION_REASON_UNSPECIFIED:
	case TERMINATION_REASON_FEAS_POLISH_SUCCESS:
	return "FEAS_POLISH_SUCCESS";
	default:
	return "UNSPECIFIED";
	}
	}

2. Missing Case in Python Bindings: The Python binding implementation is missing the case for FEAS_POLISH_SUCCESS.
   

   cuPDLPx/python_bindings/_core_bindings.cpp

   Lines 163 to 181 in 4ff479e

   	static const char *status_to_str(termination_reason_t r)
   	{
   	switch (r)
   	{
   	case TERMINATION_REASON_OPTIMAL:
   	return "OPTIMAL";
   	case TERMINATION_REASON_PRIMAL_INFEASIBLE:
   	return "PRIMAL_INFEASIBLE";
   	case TERMINATION_REASON_DUAL_INFEASIBLE:
   	return "DUAL_INFEASIBLE";
   	case TERMINATION_REASON_TIME_LIMIT:
   	return "TIME_LIMIT";
   	case TERMINATION_REASON_ITERATION_LIMIT:
   	return "ITERATION_LIMIT";
   	case TERMINATION_REASON_UNSPECIFIED:
   	default:
   	return "UNSPECIFIED";
   	}
   	}