Added functions to get the index of the minimum element of a pbqp matrix row/column.

[r25356]

diff --git a/matrix.c b/matrix.c
index b7016af..5dc33b6 100644 (file)
--- a/matrix.c
+++ b/matrix.c
@@ -149,6 +149,34 @@ num pbqp_matrix_get_col_min(pbqp_matrix *matrix, unsigned col_index, vector *fla
        return min;
 }
 
+unsigned pbqp_matrix_get_col_min_index(pbqp_matrix *matrix, unsigned col_index, vector *flags)
+{
+       unsigned row_index;
+       unsigned min_index;
+       num min = INF_COSTS;
+
+       assert(matrix);
+       assert(flags);
+       assert(matrix->rows == flags->len);
+
+       unsigned col_len = matrix->cols;
+       unsigned row_len = matrix->rows;
+
+       for (row_index = 0; row_index < row_len; ++row_index) {
+               /* Ignore virtual deleted columns. */
+               if (flags->entries[row_index].data == INF_COSTS) continue;
+
+               num elem = matrix->entries[row_index * col_len + col_index];
+
+               if (elem < min) {
+                       min = elem;
+                       min_index = row_index;
+               }
+       }
+
+       return min_index;
+}
+
 void pbqp_matrix_sub_col_value(pbqp_matrix *matrix, unsigned col_index,
                vector *flags, num value)
 {
@@ -201,6 +229,33 @@ num pbqp_matrix_get_row_min(pbqp_matrix *matrix, unsigned row_index, vector *fla
        return min;
 }
 
+unsigned pbqp_matrix_get_row_min_index(pbqp_matrix *matrix, unsigned row_index, vector *flags)
+{
+       unsigned col_index;
+       unsigned min_index;
+       num min = INF_COSTS;
+
+       assert(matrix);
+       assert(flags);
+       assert(matrix->cols == flags->len);
+
+       unsigned len = flags->len;
+
+       for (col_index = 0; col_index < len; ++col_index) {
+               /* Ignore virtual deleted columns. */
+               if (flags->entries[col_index].data == INF_COSTS) continue;
+
+               num elem = matrix->entries[row_index * len + col_index];
+
+               if (elem < min) {
+                       min = elem;
+                       min_index = col_index;
+               }
+       }
+
+       return min_index;
+}
+
 void pbqp_matrix_sub_row_value(pbqp_matrix *matrix, unsigned row_index,
                vector *flags, num value)
 {

diff --git a/matrix.h b/matrix.h
index aa19ae1..fb9dcf4 100644 (file)
--- a/matrix.h
+++ b/matrix.h
@@ -20,6 +20,9 @@ void pbqp_matrix_set(pbqp_matrix *mat, unsigned row, unsigned col, num value);
 num pbqp_matrix_get_col_min(pbqp_matrix *matrix, unsigned col_index, vector *flags);
 num pbqp_matrix_get_row_min(pbqp_matrix *matrix, unsigned row_index, vector *flags);
 
+unsigned pbqp_matrix_get_col_min_index(pbqp_matrix *matrix, unsigned col_index, vector *flags);
+unsigned pbqp_matrix_get_row_min_index(pbqp_matrix *matrix, unsigned row_index, vector *flags);
+
 void pbqp_matrix_set_col_value(pbqp_matrix *mat, unsigned col, num value);
 void pbqp_matrix_set_row_value(pbqp_matrix *mat, unsigned row, num value);