From 540db2108e93dcf1ba7bb19dd502828b4fe5c8ff Mon Sep 17 00:00:00 2001
From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Tue, 8 Jun 2021 19:36:52 -0700
Subject: [PATCH] remove unused SparseMatrix_page_rank

---
 lib/sparse/SparseMatrix.c | 108 --------------------------------------
 lib/sparse/SparseMatrix.h |   3 --
 2 files changed, 111 deletions(-)

diff --git a/lib/sparse/SparseMatrix.c b/lib/sparse/SparseMatrix.c
index 03deca89b..8e7b5c17e 100644
--- a/lib/sparse/SparseMatrix.c
+++ b/lib/sparse/SparseMatrix.c
@@ -3346,111 +3346,3 @@ SparseMatrix SparseMatrix_distance_matrix_khops(int khops, SparseMatrix D0, int
   return D;
 
 }
-
-void SparseMatrix_page_rank(SparseMatrix A, real teleport_probablity, int weighted, real epsilon, real **page_rank){
-  /* A(i,j)/Sum_k A(i,k) gives the probablity of the random surfer walking from i to j
-     A: n x n  square matrix
-     weighted: whether to use the wedge weights (matrix entries)
-     page_rank: array of length n. If *page_rank was null on entry, will be assigned.
-
- */
-  int n = A->n;
-  int i, j;
-  int *ia = A->ia, *ja = A->ja;
-  real *x, *y, *diag, res;
-  real *a = NULL;
-  int iter = 0;
-
-  assert(A->m == n);
-  assert(teleport_probablity >= 0);
-
-  if (weighted){
-    switch (A->type){
-    case MATRIX_TYPE_REAL:
-      a = (real*) A->a;
-      break;
-    case MATRIX_TYPE_COMPLEX:/* take real part */
-      a = MALLOC(sizeof(real)*n);
-      for (i = 0; i < n; i++) a[i] = ((real*) A->a)[2*i];
-      break;
-    case MATRIX_TYPE_INTEGER:
-      a = MALLOC(sizeof(real)*n);
-      for (i = 0; i < n; i++) a[i] = ((int*) A->a)[i];
-      break;
-    case MATRIX_TYPE_PATTERN:
-    case MATRIX_TYPE_UNKNOWN:
-    default:
-      weighted = FALSE;
-      break;
-    }
-  }
-
-
-  if (!(*page_rank)) *page_rank = MALLOC(sizeof(real)*n);
-  x = *page_rank;
-
-  diag = MALLOC(sizeof(real)*n);
-  for (i = 0; i < n; i++) diag[i] = 0;
-  y = MALLOC(sizeof(real)*n);
-
-  for (i = 0; i < n; i++) x[i] = 1./n;
-
-  /* find the column sum */
-  if (weighted){
-    for (i = 0; i < n; i++){
-      for (j = ia[i]; j < ia[i+1]; j++){
-	if (ja[j] == i) continue;
-	diag[i] += fabs(a[j]);
-      }
-    }
-  } else {
-    for (i = 0; i < n; i++){
-      for (j = ia[i]; j < ia[i+1]; j++){
-	if (ja[j] == i) continue;
-	diag[i]++;
-      }
-    }
-  }
-  for (i = 0; i < n; i++) diag[i] = 1./MAX(diag[i], MACHINEACC);
-
-  /* iterate */
-  do {
-    iter++;
-    for (i = 0; i < n; i++) y[i] = 0;
-    if (weighted){
-      for (i = 0; i < n; i++){
-	for (j = ia[i]; j < ia[i+1]; j++){
-	  if (ja[j] == i) continue;
-	  y[ja[j]] += a[j]*x[i]*diag[i];
-	}
-      }
-    } else {
-      for (i = 0; i < n; i++){
-	for (j = ia[i]; j < ia[i+1]; j++){
-	  if (ja[j] == i) continue;
-	  y[ja[j]] += x[i]*diag[i];
-	}
-      }
-    }
-    for (i = 0; i < n; i++){
-      y[i] = (1-teleport_probablity)*y[i] + teleport_probablity/n;
-    }
-
-    /*
-    fprintf(stderr,"\n============\nx=");
-    for (i = 0; i < n; i++) fprintf(stderr,"%f,",x[i]);
-    fprintf(stderr,"\nx=");
-    for (i = 0; i < n; i++) fprintf(stderr,"%f,",y[i]);
-    fprintf(stderr,"\n");
-    */
-
-    res = 0;
-    for (i = 0; i < n; i++) res += fabs(x[i] - y[i]);
-    if (Verbose) fprintf(stderr,"page rank iter -- %d, res = %f\n",iter, res);
-    memcpy(x, y, sizeof(real)*n);
-  } while (res > epsilon);
-
-  FREE(y);
-  FREE(diag);
-  if (a && a != A->a) FREE(a);
-}
diff --git a/lib/sparse/SparseMatrix.h b/lib/sparse/SparseMatrix.h
index 24aa9817a..d90de1540 100644
--- a/lib/sparse/SparseMatrix.h
+++ b/lib/sparse/SparseMatrix.h
@@ -132,9 +132,6 @@ void SparseMatrix_khair_decomposition(SparseMatrix A, int *hairness_max0, int **
 
 SparseMatrix SparseMatrix_from_dense(int m, int n, real *x);
 
-void SparseMatrix_page_rank(SparseMatrix A, real teleport_probablity, int weighted, real epsilon, real **page_rank);
-
-
 #define SparseMatrix_set_undirected(A) set_flag((A)->property, MATRIX_UNDIRECTED)
 #define SparseMatrix_set_symmetric(A) set_flag((A)->property, MATRIX_SYMMETRIC)
 #define SparseMatrix_set_pattern_symmetric(A) set_flag((A)->property, MATRIX_PATTERN_SYMMETRIC)
-- 
2.40.0