star-line

commit d22920c3f0f714d80ddaf777517fb27a2043be6b
parent 7b34ed7cc0268d32267ef232c9f3cb8535ef07f1
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 26 May 2022 12:37:27 +0200

Add the sln_mesh_eval function

Diffstat:
M
src/sln.h
 | 
5
+++++
M
src/sln_line.c
 | 
2
+-
M
src/sln_tree.c
 | 
45
+++++++++++++++++++++++++++++++++++++++++++++
M
src/sln_tree_build.c
 | 
2
+-

4 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/src/sln.h b/src/sln.h
@@ -276,6 +276,11 @@ sln_node_get_mesh
    const struct sln_node* node,
    struct sln_mesh* mesh);
 
+SLN_API float
+sln_mesh_eval
+  (const struct sln_mesh* mesh,
+   const float wavenumber); /* In cm^-1 */
+
 SLN_API res_T
 sln_tree_write
   (const struct sln_tree* tree,
diff --git a/src/sln_line.c b/src/sln_line.c
@@ -634,7 +634,7 @@ line_mesh
   darray_double_init(tree->mixture->sln->allocator, &wavenumbers);
 
   /* Adjust the hint on the number of vertices. This is not actually the real
-   * number of vertices but a adjusted hint on it. This new value ensures that
+   * number of vertices but an adjusted hint on it. This new value ensures that
    * it is a power of 2 included in [MIN_NVERTICES_HINT, MAX_NVERTICES_HINT] */
   nvertices_adjusted = CLAMP
     (nvertices_hint, MIN_NVERTICES_HINT, MAX_NVERTICES_HINT);
diff --git a/src/sln_tree.c b/src/sln_tree.c
@@ -23,6 +23,8 @@
 #include "sln_tree_c.h"
 
 #include <star/shtr.h>
+
+#include <rsys/algorithm.h>
 #include <rsys/cstr.h>
 
 /*******************************************************************************
@@ -109,6 +111,16 @@ store_input_args
   return RES_OK;
 }
 
+static INLINE int
+cmp_nu_vtx(const void* key, const void* item)
+{
+  const float nu = *((const float*)key);
+  const struct sln_vertex* vtx = item;
+  if(nu < vtx->wavenumber) return -1;
+  if(nu > vtx->wavenumber) return +1;
+  return 0;
+}
+
 static void
 release_tree(ref_T* ref)
 {
@@ -317,6 +329,39 @@ sln_node_get_mesh
   return RES_OK;
 }
 
+float
+sln_mesh_eval(const struct sln_mesh* mesh, const float nu)
+{
+  const struct sln_vertex* vtx0 = NULL;
+  const struct sln_vertex* vtx1 = NULL;
+  size_t n; /* #vertices */
+  float u; /* Linear interpolation paraeter */
+  ASSERT(mesh && nu >= 0);
+
+  n = mesh->nvertices;
+
+  /* Handle special cases */
+  if(n == 0) return 0;
+  if(n == 1) return mesh->vertices[0].ka;
+  if(nu <= mesh->vertices[0].wavenumber) return mesh->vertices[0].ka;
+  if(nu >= mesh->vertices[n-1].wavenumber) return mesh->vertices[n-1].ka;
+
+  /* Dichotomic search of the mesh vertex whose wavenumber is greater than the
+   * submitted wavenumber 'nu' */
+  vtx1 = search_lower_bound(&nu, mesh->vertices, n, sizeof(*vtx1), cmp_nu_vtx);
+  vtx0 = vtx1 - 1;
+  ASSERT(vtx1); /* A vertex is necessary found ...*/
+  ASSERT(vtx1 > mesh->vertices); /* ... and it cannot be the first one */
+
+  /* Compute the linear interpolation parameter */
+  u = (nu - vtx0->wavenumber) / (vtx1->wavenumber - vtx0->wavenumber);
+  u = CLAMP(u, 0, 1); /* Handle numerical imprecisions */
+
+  if(u == 0) return vtx0->ka;
+  if(u == 1) return vtx1->ka;
+  return u*(vtx1->ka - vtx0->ka) + vtx0->ka;
+}
+
 res_T
 sln_tree_write(const struct sln_tree* tree, FILE* stream)
 {
diff --git a/src/sln_tree_build.c b/src/sln_tree_build.c
@@ -294,7 +294,7 @@ partition_lines
       const size_t split = NODE(inode)->range[0] + (nlines + 1/*ceil*/)/2;
 
       /* Compute the index toward the 2 children (first is the left child,
-       * followed by the righ child) */
+       * followed by the right child) */
       size_t ichildren = darray_node_size_get(&tree->nodes);
 
       ASSERT(NODE(inode)->range[0] <= split);