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-rw-r--r--gsl-1.9/sort/sortvec_source.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/gsl-1.9/sort/sortvec_source.c b/gsl-1.9/sort/sortvec_source.c
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+/*
+ * Implement Heap sort -- direct and indirect sorting
+ * Based on descriptions in Sedgewick "Algorithms in C"
+ *
+ * Copyright (C) 1999 Thomas Walter
+ *
+ * 18 February 2000: Modified for GSL by Brian Gough
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This source is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+static inline void FUNCTION (my, downheap) (BASE * data, const size_t stride, const size_t N, size_t k);
+
+static inline void
+FUNCTION (my, downheap) (BASE * data, const size_t stride, const size_t N, size_t k)
+{
+ BASE v = data[k * stride];
+
+ while (k <= N / 2)
+ {
+ size_t j = 2 * k;
+
+ if (j < N && data[j * stride] < data[(j + 1) * stride])
+ {
+ j++;
+ }
+
+ if (!(v < data[j * stride])) /* avoid infinite loop if nan */
+ {
+ break;
+ }
+
+ data[k * stride] = data[j * stride];
+
+ k = j;
+ }
+
+ data[k * stride] = v;
+}
+
+void
+TYPE (gsl_sort) (BASE * data, const size_t stride, const size_t n)
+{
+ size_t N;
+ size_t k;
+
+ if (n == 0)
+ {
+ return; /* No data to sort */
+ }
+
+ /* We have n_data elements, last element is at 'n_data-1', first at
+ '0' Set N to the last element number. */
+
+ N = n - 1;
+
+ k = N / 2;
+ k++; /* Compensate the first use of 'k--' */
+ do
+ {
+ k--;
+ FUNCTION (my, downheap) (data, stride, N, k);
+ }
+ while (k > 0);
+
+ while (N > 0)
+ {
+ /* first swap the elements */
+ BASE tmp = data[0 * stride];
+ data[0 * stride] = data[N * stride];
+ data[N * stride] = tmp;
+
+ /* then process the heap */
+ N--;
+
+ FUNCTION (my, downheap) (data, stride, N, 0);
+ }
+}
+
+void
+TYPE (gsl_sort_vector) (TYPE (gsl_vector) * v)
+{
+ TYPE (gsl_sort) (v->data, v->stride, v->size) ;
+}
+