{ps,nl}solve: constify exported colloc grid

Reduces compiler warnings.

1 files changed, 1 insertions, 1 deletions

diff --git a/nlsolve.h b/nlsolve.h
index d0e3c38..3f3987c 100644
--- a/nlsolve.h
+++ b/nlsolve.h
@@ -82,7 +82,7 @@ typedef struct NLSolveContext {
      *
      * Set by the solver after tdi_nlsolve_context_init().
      */
-    double *(*colloc_grid)[2];
+    const double * const (*colloc_grid)[2];
 
     // solver parameters
     unsigned int maxiter;