From b45e563ddbc72c8f19267e85dd30d7c0283ab441 Mon Sep 17 00:00:00 2001
From: "Daniel R. Reynolds" <reynolds@smu.edu>
Date: Tue, 16 Jul 2024 13:29:04 -0500
Subject: [PATCH] Updated SPRKStep and LSRKStep to only request Lagrange
 interpolation (not to construct the Lagrange module directly).

---
 src/arkode/arkode_lsrkstep.c | 11 ++---------
 src/arkode/arkode_sprkstep.c |  2 +-
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/src/arkode/arkode_lsrkstep.c b/src/arkode/arkode_lsrkstep.c
index da389c9ac5..87d4d60992 100644
--- a/src/arkode/arkode_lsrkstep.c
+++ b/src/arkode/arkode_lsrkstep.c
@@ -147,15 +147,8 @@ void* LSRKStepCreate(ARKRhsFn fe, ARKRhsFn fi, sunrealtype t0, N_Vector y0,
     return (NULL);
   }
 
-  /* Specify Interpolation Type */
-  retval = ARKodeSetInterpolantType(ark_mem, ARK_INTERP_LAGRANGE);
-  if (retval != ARK_SUCCESS)
-  {
-    arkProcessError(ark_mem, retval, __LINE__, __func__, __FILE__,
-                    "Unable to specify interpolation type");
-    ARKodeFree((void**)&ark_mem);
-    return (NULL);
-  }
+  /* Specify preferred interpolation type */
+  ark_mem->interp_type = ARK_INTERP_LAGRANGE;
 
   return ((void*)ark_mem);
 }
diff --git a/src/arkode/arkode_sprkstep.c b/src/arkode/arkode_sprkstep.c
index 0ae21c2741..739e3ba885 100644
--- a/src/arkode/arkode_sprkstep.c
+++ b/src/arkode/arkode_sprkstep.c
@@ -151,7 +151,7 @@ void* SPRKStepCreate(ARKRhsFn f1, ARKRhsFn f2, sunrealtype t0, N_Vector y0,
 
   /* SPRKStep uses Lagrange interpolation by default, since Hermite is
      less compatible with these methods. */
-  ARKodeSetInterpolantType(ark_mem, ARK_INTERP_LAGRANGE);
+  ark_mem->interp_type = ARK_INTERP_LAGRANGE;
 
   /* Initialize main ARKODE infrastructure */
   retval = arkInit(ark_mem, t0, y0, FIRST_INIT);