Sparse ten_J and ten_J_colind memory

PiperOrigin-RevId: 868834376
Change-Id: Iec92d9e09e3134666895e54a78cb02439d74a4de

python/mujoco/introspect/structs.py

@@ -1242,11 +1242,6 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  type=ValueType(name='mjtSize'),
                  doc='number of non-zeros in sparse actuator_moment matrix',
              ),
-             StructFieldDecl(
-                 name='nJten',
-                 type=ValueType(name='mjtSize'),
-                 doc='number of non-zeros in sparse ten_J matrix',
-             ),
              StructFieldDecl(
                  name='ngravcomp',
                  type=ValueType(name='mjtSize'),
@@ -5834,7 +5829,7 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                      inner_type=ValueType(name='int'),
                  ),
                  doc='column indices in sparse Jacobian',
-                 array_extent=('nJten',),
+                 array_extent=('ntendon', 'nv'),
              ),
              StructFieldDecl(
                  name='ten_J',
@@ -5842,7 +5837,7 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                      inner_type=ValueType(name='mjtNum'),
                  ),
                  doc='tendon Jacobian',
-                 array_extent=('nJten',),
+                 array_extent=('ntendon', 'nv'),
              ),
              StructFieldDecl(
                  name='ten_length',

python/mujoco/structs_wrappers.cc

@@ -747,6 +747,7 @@ void MjDataWrapper::Serialize(std::ostream& output) const {
 
   // Write buffer and arena contents
   {
+    MJDATA_POINTERS_PREAMBLE((this->model_->get()))
 
 #define X(type, name, nr, nc)    \
   WriteBytes(output, ptr_->name, \
@@ -826,6 +827,7 @@ MjDataWrapper MjDataWrapper::Deserialize(std::istream& input) {
 
   // Read buffer and arena contents
   {
+    MJDATA_POINTERS_PREAMBLE((&m))
 
 #define X(type, name, nr, nc) \
   ReadBytes(input, d->name, sizeof(type) * (m.nr) * (nc));