Merge pull request #664 from stan-dev/bugfix/elementwise-pow

Bugfix/elementwise pow and empty matrices

Author: rok-cesnovar

src/middle/Stan_math_signatures.ml

@@ -1079,11 +1079,18 @@ let () =
   add_unqualified ("is_nan", ReturnType UInt, [UReal]) ;
   add_binary "lbeta" ;
   add_binary "lchoose" ;
-  add_unqualified
-    ("linspaced_array", ReturnType (UArray UReal), [UInt; UReal; UReal]) ;
-  add_unqualified
-    ("linspaced_row_vector", ReturnType URowVector, [UInt; UReal; UReal]) ;
-  add_unqualified ("linspaced_vector", ReturnType UVector, [UInt; UReal; UReal]) ;
+  add_qualified
+    ( "linspaced_array"
+    , ReturnType (UArray UReal)
+    , [(DataOnly, UInt); (DataOnly, UReal); (DataOnly, UReal)] ) ;
+  add_qualified
+    ( "linspaced_row_vector"
+    , ReturnType URowVector
+    , [(DataOnly, UInt); (DataOnly, UReal); (DataOnly, UReal)] ) ;
+  add_qualified
+    ( "linspaced_vector"
+    , ReturnType UVector
+    , [(DataOnly, UInt); (DataOnly, UReal); (DataOnly, UReal)] ) ;
   add_unqualified ("lkj_corr_cholesky_log", ReturnType UReal, [UMatrix; UReal]) ;
   add_unqualified ("lkj_corr_cholesky_lpdf", ReturnType UReal, [UMatrix; UReal]) ;
   add_unqualified ("lkj_corr_cholesky_rng", ReturnType UMatrix, [UInt; UReal]) ;

src/stan_math_backend/Expression_gen.ml

@@ -219,8 +219,7 @@ and gen_operator_app = function
       fun ppf es ->
         pp_scalar_binary ppf "(%a@ /@ %a)" "elt_divide(@,%a,@ %a)" es
   | Pow -> fun ppf es -> pp_binary_f ppf "pow" es
-  | EltPow ->
-      fun ppf es -> pp_scalar_binary ppf "(%a@ *@ %a)" "pow(@,%a,@ %a)" es
+  | EltPow -> fun ppf es -> pp_binary_f ppf "pow" es
   | Equals -> fun ppf es -> pp_binary_f ppf "logical_eq" es
   | NEquals -> fun ppf es -> pp_binary_f ppf "logical_neq" es
   | Less -> fun ppf es -> pp_binary_f ppf "logical_lt" es
@@ -358,11 +357,16 @@ and pp_user_defined_fun ppf (f, es) =
 and pp_compiler_internal_fn ut f ppf es =
   let pp_array_literal ppf es =
     let pp_add_method ppf () = pf ppf ")@,.add(" in
-    pf ppf "stan::math::array_builder<%a>()@,.add(%a)@,.array()"
-      pp_unsizedtype_local
-      (promote_adtype es, promote_unsizedtype es)
-      (list ~sep:pp_add_method pp_expr)
-      es
+    if List.length es = 0 then
+      pf ppf "stan::math::array_builder<%a>()@,.add(0)@,.array()"
+        pp_unsizedtype_local
+        (promote_adtype es, promote_unsizedtype es)
+    else
+      pf ppf "stan::math::array_builder<%a>()@,.add(%a)@,.array()"
+        pp_unsizedtype_local
+        (promote_adtype es, promote_unsizedtype es)
+        (list ~sep:pp_add_method pp_expr)
+        es
   in
   match Internal_fun.of_string_opt f with
   | Some FnMakeArray -> pp_array_literal ppf es

src/stan_math_backend/Stan_math_code_gen.ml

@@ -724,7 +724,8 @@ using stan::model::index_min_max;
 using stan::model::index_multi;
 using stan::model::index_omni;
 using stan::model::nil_index_list;
-using namespace stan::math; |}
+using namespace stan::math;
+using stan::math::pow; |}
 
 (** Functions needed in the model class not defined yet in stan math.
  FIXME: Move these to the Stan repo when these repos are joined. 

test/integration/good/code-gen/cl.expected

@@ -54,7 +54,8 @@ using stan::model::index_min_max;
 using stan::model::index_multi;
 using stan::model::index_omni;
 using stan::model::nil_index_list;
-using namespace stan::math; 
+using namespace stan::math;
+using stan::math::pow; 
 
 static int current_statement__ = 0;
 static const std::vector<string> locations_array__ = {" (found before start of program)",