Fixing conversion issues

src/core/math/ParserOMP.cpp

@@ -51,7 +51,7 @@ void FunctionParserOMP::parse(const std::string & eq)
    #ifdef _OPENMP
    #pragma omp parallel for schedule(static)
    #endif
-   for (int t = 0; t < omp_get_max_threads(); ++t)
+   for (uint_t t = 0; t < omp_get_max_threads(); ++t)
    {
       parser_[t].parse(eq);
    }
@@ -61,7 +61,7 @@ double FunctionParserOMP::evaluate(const std::map<std::string,double> & symbolTa
 {
    WALBERLA_ASSERT_EQUAL(omp_get_max_threads(), num_parsers_);
 
-   return parser_[omp_get_thread_num()].evaluate(symbolTable);
+   return parser_[uint_c(omp_get_thread_num())].evaluate(symbolTable);
 }