chore: remove dead code, add source file comments, fix comment style

Dead code removed:
- Remove commented-out un_normalize_a_p() from scs_matrix.c (25 lines)
  and its commented-out declaration from scs_matrix.h
- Remove duplicate cumsum() declaration from scs_matrix.h (already in
  csparse.h)

Source file doc comments added:
- exp_cone.c, rw.c, linalg.c, normalize.c, util.c

Comment style consistency:
- Convert // C++ comments to /* */ C comments in cones.h and
  util_spectral_cones.h to match the rest of the codebase

Co-Authored-By: Claude Opus 4.6 <[email protected]>

Author: bodono

include/cones.h

@@ -12,9 +12,9 @@ extern "C" {
 #include <string.h>
 
 #ifdef USE_SPECTRAL_CONES
-#include "util_spectral_cones.h" // for newton_stats
+#include "util_spectral_cones.h" /* for Newton_stats */
 
-// macro for time measurements of SpectralSCS
+/* macro for time measurements of SpectralSCS */
 #ifdef SPECTRAL_TIMING_FLAG
 #define SPECTRAL_TIMING(action) action
 #else
@@ -55,7 +55,7 @@ struct SCS_CONE_WORK {
   Value_index *work_ell1;
   scs_float *work_ell1_proj;
 
-  // used for timing spectral vector cone and spectral matrix cone projections
+  /* used for timing spectral vector cone and spectral matrix cone projections */
   SPECTRAL_TIMING(scs_float tot_time_mat_cone_proj;)
   SPECTRAL_TIMING(scs_float tot_time_vec_cone_proj;)
 

include/util_spectral_cones.h

@@ -23,7 +23,7 @@ void non_neg_proj(const scs_float *src, scs_float *dst, scs_int n);
 scs_float sum_log(const scs_float *x, scs_int n);
 scs_float min_vec(const scs_float *vec, scs_int n);
 
-// used for sorting in ell1-norm cone and sum of largest cone.
+/* used for sorting in ell1-norm cone and sum of largest cone. */
 typedef struct {
   scs_float value;
   int index;
@@ -32,10 +32,10 @@ typedef struct {
 typedef struct {
   int iter;
 
-  // if plain Newton computed the projection or if an IPM was used
+  /* if plain Newton computed the projection or if an IPM was used */
   int newton_success;
 
-  // dual_res, pri_res, complementarity for the projection problem
+  /* dual_res, pri_res, complementarity for the projection problem */
   scs_float residuals[3];
 } Newton_stats;
 

linsys/scs_matrix.c

@@ -456,30 +456,3 @@ ScsScaling *SCS(normalize_a_p)(ScsMatrix *P, ScsMatrix *A, ScsConeWork *cone) {
   return scal;
 }
 
-/*
-void SCS(un_normalize_a_p)(ScsMatrix *A, ScsMatrix *P, const ScsScaling *scal) {
-  scs_int i, j;
-  scs_float *D = scal->D;
-  scs_float *E = scal->E;
-  for (i = 0; i < A->n; ++i) {
-    SCS(scale_array)
-    (&(A->x[A->p[i]]), 1. / E[i], A->p[i + 1] - A->p[i]);
-  }
-  for (i = 0; i < A->n; ++i) {
-    for (j = A->p[i]; j < A->p[i + 1]; ++j) {
-      A->x[j] /= D[A->i[j]];
-    }
-  }
-  if (P) {
-    for (i = 0; i < P->n; ++i) {
-      SCS(scale_array)
-      (&(P->x[P->p[i]]), 1. / E[i], P->p[i + 1] - P->p[i]);
-    }
-    for (i = 0; i < P->n; ++i) {
-      for (j = P->p[i]; j < P->p[i + 1]; ++j) {
-        P->x[j] /= E[P->i[j]];
-      }
-    }
-  }
-}
-*/

linsys/scs_matrix.h

@@ -20,20 +20,13 @@ extern "C" {
  * boundaries */
 ScsScaling *SCS(normalize_a_p)(ScsMatrix *P, ScsMatrix *A, ScsConeWork *cone);
 
-/* unnormalizes A matrix, unnormalizes by w->D and w->E */
-/* void SCS(un_normalize_a_p)(ScsMatrix *A, ScsMatrix *P, const ScsScaling
- * *scal);
- */
-
 /* to free the memory allocated in a ScsMatrix (called on A and P at finish) */
 void SCS(free_scs_matrix)(ScsMatrix *A);
 
 /* copies A (instead of in-place normalization), returns 0 for failure,
  * allocates memory for dstp	*/
 scs_int SCS(copy_matrix)(ScsMatrix **dstp, const ScsMatrix *src);
 
-scs_float SCS(cumsum)(scs_int *p, scs_int *c, scs_int n);
-
 /**
  * Validate the linear system inputs, returns < 0 if not valid inputs.
  *

src/exp_cone.c

@@ -1,3 +1,8 @@
+/*
+ * Exponential cone projection via Newton's method.
+ * Handles both primal and dual exponential cones using Moreau decomposition.
+ */
+
 #include "cones.h"
 #include "glbopts.h"
 #include "linalg.h"

src/linalg.c

@@ -1,3 +1,9 @@
+/*
+ * Dense linear algebra operations: norms, dot products, scaling, axpy.
+ * Has two implementations: a plain C fallback and an optimized BLAS version
+ * (selected at compile time via USE_LAPACK).
+ */
+
 #include "linalg.h"
 #include "scs_blas.h"
 #include <math.h>

src/normalize.c

@@ -1,3 +1,9 @@
+/*
+ * Problem data normalization (equilibration) of b and c vectors,
+ * and solution normalization/un-normalization routines.
+ * Matrix normalization (A, P) is in linsys/scs_matrix.c.
+ */
+
 #include "normalize.h"
 
 #include "linalg.h"

src/rw.c

@@ -1,3 +1,8 @@
+/*
+ * Read/write routines for serializing SCS problem data to binary files
+ * and logging solve progress to CSV. Compiled as no-ops when NO_READ_WRITE=1.
+ */
+
 #include "rw.h"
 
 #include <errno.h>

src/util.c

@@ -1,3 +1,8 @@
+/*
+ * Utility functions: platform-specific timers, deep copy helpers for
+ * ScsData/ScsSettings, memory deallocation, and default settings.
+ */
+
 #include "util.h"
 
 #include "glbopts.h"