Remove use of diagnum in solver

PiperOrigin-RevId: 759021147
Change-Id: I9e5c85b6542380780fc487781398f406ddaad51b

doc/includes/references.h

@@ -392,7 +392,6 @@ struct mjData_ {
   mjtNum* iacc_smooth;       // unconstrained acceleration                       (nidof x 1)
   int*    iM_rownnz;         // inertia: non-zeros in each row                   (nidof x 1)
   int*    iM_rowadr;         // inertia: address of each row in iM_colind        (nidof x 1)
-  int*    iM_diagnum;        // inertia: num of consecutive diagonal elements    (nidof x 1)
   int*    iM_colind;         // inertia: column indices of non-zeros             (nC x 1)
   mjtNum* iM;                // total inertia (sparse)                           (nC x 1)
   mjtNum* iLD;               // L'*D*L factorization of M (sparse)               (nC x 1)

include/mujoco/mjdata.h

@@ -420,7 +420,6 @@ struct mjData_ {
   mjtNum* iacc_smooth;       // unconstrained acceleration                       (nidof x 1)
   int*    iM_rownnz;         // inertia: non-zeros in each row                   (nidof x 1)
   int*    iM_rowadr;         // inertia: address of each row in iM_colind        (nidof x 1)
-  int*    iM_diagnum;        // inertia: num of consecutive diagonal elements    (nidof x 1)
   int*    iM_colind;         // inertia: column indices of non-zeros             (nC x 1)
   mjtNum* iM;                // total inertia (sparse)                           (nC x 1)
   mjtNum* iLD;               // L'*D*L factorization of M (sparse)               (nC x 1)

include/mujoco/mjxmacro.h

@@ -758,7 +758,6 @@
     X( mjtNum,  iacc_smooth,       MJ_D(nidof),    1 ) \
     X( int,     iM_rownnz,         MJ_D(nidof),    1 ) \
     X( int,     iM_rowadr,         MJ_D(nidof),    1 ) \
-    X( int,     iM_diagnum,        MJ_D(nidof),    1 ) \
     X( int,     iM_colind,         MJ_M(nC),       1 ) \
     X( mjtNum,  iM,                MJ_M(nC),       1 ) \
     X( mjtNum,  iLD,               MJ_M(nC),       1 ) \

python/mujoco/introspect/structs.py

@@ -6024,14 +6024,6 @@ STRUCTS: Mapping[str, StructDecl] = dict([
                  doc='inertia: address of each row in iM_colind',
                  array_extent=('nidof',),
              ),
-             StructFieldDecl(
-                 name='iM_diagnum',
-                 type=PointerType(
-                     inner_type=ValueType(name='int'),
-                 ),
-                 doc='inertia: num of consecutive diagonal elements',
-                 array_extent=('nidof',),
-             ),
              StructFieldDecl(
                  name='iM_colind',
                  type=PointerType(

src/engine/engine_island.c

@@ -544,25 +544,6 @@ void mj_island(const mjModel* m, mjData* d) {
                       d->iM, d->M);
   mju_gather(d->iLDiagInv, d->qLDiagInv, d->map_idof2dof, nidof);
 
-  // compute iM_diagnum (dof_simplenum per island)
-  int count = 0;
-  int dof_next = d->map_idof2dof[nidof-1];
-  for (int i=nidof-1; i >= 0; i--) {
-    // check if island boundary was crossed
-    int dof = d->map_idof2dof[i];
-    int island_boundary = (d->dof_island[dof] != d->dof_island[dof_next]);
-    dof_next = dof;
-
-    // accumulate and set simple dof (diagonal row) counter
-    if (m->dof_simplenum[dof] && !island_boundary) {
-      count++;    // increment counter
-    } else {
-      count = 0;  // reset
-    }
-    d->iM_diagnum[i] = count;
-  }
-
-
 
   // ------------------------------------- constraints ---------------------------------------------
 

src/engine/engine_solver.c

@@ -786,7 +786,6 @@ struct _mjCGContext {
   // inertia
   const int* M_rownnz;
   const int* M_rowadr;
-  const int* M_diagnum;
   const int* M_colind;
   const mjtNum* M;
   const mjtNum* qLD;
@@ -888,7 +887,6 @@ static void CGpointers(const mjModel* m, const mjData* d, mjCGContext* ctx, int
     // inertia
     ctx->M_rownnz         = d->M_rownnz;
     ctx->M_rowadr         = d->M_rowadr;
-    ctx->M_diagnum        = m->dof_simplenum;
     ctx->M_colind         = d->M_colind;
     ctx->M                = d->M;
     ctx->qLD              = d->qLD;
@@ -937,7 +935,6 @@ static void CGpointers(const mjModel* m, const mjData* d, mjCGContext* ctx, int
     // inertia
     ctx->M_rownnz         = d->iM_rownnz         + idofadr;
     ctx->M_rowadr         = d->iM_rowadr         + idofadr;
-    ctx->M_diagnum        = d->iM_diagnum        + idofadr;
     ctx->M_colind         = d->iM_colind;
     ctx->M                = d->iM;
     ctx->qLD              = d->iLD;

unity/Runtime/Bindings/MjBindings.cs

@@ -5004,7 +5004,6 @@ public unsafe struct mjData_ {
   public double* iacc_smooth;
   public int* iM_rownnz;
   public int* iM_rowadr;
-  public int* iM_diagnum;
   public int* iM_colind;
   public double* iM;
   public double* iLD;