From f3ae55de67780ae938b22b78f3e785eb3bef945d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?IOhannes=20m=20zm=C3=B6lnig?=
 <zmoelnig@users.sourceforge.net>
Date: Wed, 30 Mar 2005 12:07:31 +0000
Subject: fixed a bug with non-square matrices; added an argument to pivotize
 to a minimum trace (instead of a maximum)

svn path=/trunk/externals/iem/iemmatrix/; revision=2648
---
 src/mtx_pivot.c | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

(limited to 'src/mtx_pivot.c')

diff --git a/src/mtx_pivot.c b/src/mtx_pivot.c
index 1ac4804..8534021 100644
--- a/src/mtx_pivot.c
+++ b/src/mtx_pivot.c
@@ -26,6 +26,8 @@ typedef struct _mtx_pivot
   t_matrix m_post; // the post-multiply matrix
 
   t_outlet *pivo, *pre, *post;
+
+  t_int ascending;
   
 } t_mtx_pivot;
 
@@ -41,9 +43,20 @@ static void mtx_pivot_matrix(t_mtx_pivot *x, t_symbol *s, int argc, t_atom *argv
 
   int pivot_row, pivot_col;
 
-  if (argc<2){    post("mtx_pivot: crippled matrix");    return;  }
-  if ((col<1)||(row<1)) {    post("mtx_pivot: invalid dimensions");    return;  }
-  if (col*row>argc-2){    post("sparse matrix not yet supported : use \"mtx_check\"");    return;  }
+  int ascending=(x->ascending);
+
+  if (argc<2){    
+    post("mtx_pivot: crippled matrix");    
+    return;  
+  }
+  if ((col<1)||(row<1)){
+    post("mtx_pivot: invalid dimensions");    
+    return;  
+  }
+  if (col*row>argc-2){
+    post("sparse matrix not yet supported : use \"mtx_check\"");
+    return;  
+  }
 
   adjustsize(&x->m, row, col);
   adjustsize(&x->m_pre, row, row);
@@ -65,9 +78,9 @@ static void mtx_pivot_matrix(t_mtx_pivot *x, t_symbol *s, int argc, t_atom *argv
 
   /* do the pivot thing */
 
-  for (k=0; k<min_rowcol-1; k++){
+  for (k=0; k<min_rowcol; k++){
     // 1. find max_element
-    t_matrixfloat max = 0;
+    t_matrixfloat tmp = fabsf(buffer[k*(1+col)]);
     pivot_row = pivot_col = k;
 
     for(i=k; i<row; i++){
@@ -76,14 +89,14 @@ static void mtx_pivot_matrix(t_mtx_pivot *x, t_symbol *s, int argc, t_atom *argv
       j=col-k;
       while(j--){
 	t_matrixfloat f = fabsf(*buf++);
-	if (f>max) {
-	  max=f;
+	if ((ascending && f>tmp) || (!ascending && f<tmp)) {
+	  tmp=f;
 	  pivot_row = i;
 	  pivot_col = col-j-1;
 	}
       }
     }
-    // 2. move max el to [k,k]
+    // 2. move tmp el to [k,k]
     // 2a swap rows
     if (k-pivot_row) {
       t_matrixfloat *oldrow=buffer+col*k;
@@ -127,7 +140,9 @@ static void mtx_pivot_matrix(t_mtx_pivot *x, t_symbol *s, int argc, t_atom *argv
   }
   i=row;
   m_pre = x->m_pre.atombuffer+2;
-  while(i--)SETFLOAT(m_pre+i_pre[i]+i*col, 1);
+  while(i--){
+    SETFLOAT(m_pre+i_pre[i]+i*row, 1);
+  }
 
   
   outlet_anything(x->post, gensym("matrix"), 2+col*col, x->m_post.atombuffer);
@@ -142,7 +157,7 @@ static void mtx_pivot_free(t_mtx_pivot *x)
   matrix_free(&x->m_post);
 }
 
-static void *mtx_pivot_new(void)
+static void *mtx_pivot_new(t_floatarg f)
 {
   t_mtx_pivot *x = (t_mtx_pivot *)pd_new(mtx_pivot_class);
 
@@ -150,6 +165,8 @@ static void *mtx_pivot_new(void)
   x->pre  = outlet_new(&x->x_obj, 0);
   x->post = outlet_new(&x->x_obj, 0);
 
+  x->ascending = (f < 0.f)?0:1;
+
   x->m.atombuffer = x->m_pre.atombuffer = x->m_post.atombuffer = 0;
   x->m.row = x->m.col = x->m_pre.row = x->m_pre.col = x->m_post.row = x->m_post.col = 0;
 
@@ -159,7 +176,8 @@ static void *mtx_pivot_new(void)
 void mtx_pivot_setup(void)
 {
   mtx_pivot_class = class_new(gensym("mtx_pivot"), (t_newmethod)mtx_pivot_new, (t_method)mtx_pivot_free,
-			      sizeof(t_mtx_pivot), 0, 0, 0);
+			      sizeof(t_mtx_pivot), 0, 
+			      A_DEFFLOAT, 0);
   class_addmethod(mtx_pivot_class, (t_method)mtx_pivot_matrix, gensym("matrix"), A_GIMME, 0);
 
   class_sethelpsymbol(mtx_pivot_class, gensym("iemmatrix/mtx_transpose"));
-- 
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