Support for GNU Scientific Library

loopy/target/c/__init__.py

@@ -846,6 +846,36 @@
             yield ("08_c_math", "#include <math.h>")
 
 
+class GSLCallable(ScalarCallable):
+    @override
+    def with_types(self,
+                   arg_id_to_dtype: Mapping[int | str, LoopyType],
+                   clbl_inf_ctx: CallablesInferenceContext,
+               ) -> tuple[Self, CallablesInferenceContext]:
+        name = self.name
+
+        for id in arg_id_to_dtype:
+            if not isinstance(id, int):
+                raise LoopyError(f"'{name}' can take only positional arguments")
+
+        arg_num_to_dtype = {cast("int", id): t for id, t in arg_id_to_dtype.items()}
+        arg_num_to_dtype[-1] = arg_num_to_dtype[max(arg_num_to_dtype)]
+
+        name_in_target = f"gsl_sf_{name}"
+        return (self.copy(name_in_target=name_in_target,
+                          arg_id_to_dtype=constantdict(arg_num_to_dtype)),
+                clbl_inf_ctx)
+
+    def generate_preambles(self, target):
+        # Base GSL math header
+        yield ("40_c_gsl_math", "#include <gsl/gsl_math.h>")
+
+        # Function-specific headers for GSL special functions
+        if self.name == "hyperg_2F1":
+            # gsl_sf_hyperg_2F1 is declared in <gsl/gsl_sf_hyperg.h>
+            yield ("41_c_gsl_sf_hyperg", "#include <gsl/gsl_sf_hyperg.h>")
+
+
 def get_c_callables():
     """
     Returns an instance of :class:`InKernelCallable` if the function
@@ -866,6 +896,14 @@
     func_ids = ["bessel_jn", "bessel_yn"]
     return {id_: GNULibcCallable(id_) for id_ in func_ids}
 
+
+def get_gsl_callables():
+    # Support special functions from
+    # https://www.gnu.org/software/gsl/doc/html/specfunc.html
+    func_ids = ["hyperg_2F1"]
+    return {id_: GSLCallable(id_) for id_ in func_ids}
+
+
 # }}}
 
 
@@ -1612,6 +1650,7 @@
     def known_callables(self):
         callables = super().known_callables
         callables.update(get_gnu_libc_callables())
+        callables.update(get_gsl_callables())
         return callables