avutil: reintroduce lls1 as the 52 ABI needs it

lls1 taken from ff130d7

This is incompatible with libavcodec version
55.18.100 to 55.43.100 except 55.39.101
This incompatibility is caused by these libavcodec versions depending on
a libavutil 52 which is ABI incompatible with the previous ABI 52

you can avoid this incompatibility by upgrading your libavcodec so it
does no longer depend on the invalid ABI

See: 502ab21af0ca68f76d6112722c46d2f35c004053
See: cc6714bb16b1f0716ba43701d47273dbe9657b8b
See: 41578f70cf8aec8e7565fba1ca7e07f3dc46c3d2
See: Ticket3136
Tested-by: marillat
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit b382d09d29be90e0947295a70cdcbaa60b9030b8)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

4 files changed, 239 insertions, 0 deletions

diff --git a/libavutil/Makefile b/libavutil/Makefile
index ba759f07c0..26e8d37e1c 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -89,6 +89,7 @@ OBJS = adler32.o                                                        \
        intfloat_readwrite.o                                             \
        intmath.o                                                        \
        lfg.o                                                            \
+       lls1.o                                                           \
        lls2.o                                                           \
        log.o                                                            \
        log2_tab.o                                                       \
@@ -142,6 +143,7 @@ TESTPROGS = adler32                                                     \
             fifo                                                        \
             hmac                                                        \
             lfg                                                         \
+            lls1                                                        \
             lls2                                                        \
             md5                                                         \
             murmur3                                                     \
diff --git a/libavutil/lls1.c b/libavutil/lls1.c
new file mode 100644
index 0000000000..c452d82334
--- /dev/null
+++ b/libavutil/lls1.c
@@ -0,0 +1,180 @@
+/*
+ * linear least squares model
+ *
+ * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * linear least squares model
+ */
+
+#include <math.h>
+#include <string.h>
+
+#include "attributes.h"
+#include "version.h"
+#include "lls1.h"
+
+#if FF_API_LLS1
+
+av_cold void avpriv_init_lls(LLSModel *m, int indep_count)
+{
+    memset(m, 0, sizeof(LLSModel));
+    m->indep_count = indep_count;
+}
+
+void avpriv_update_lls(LLSModel *m, double *var, double decay)
+{
+    int i, j;
+
+    for (i = 0; i <= m->indep_count; i++) {
+        for (j = i; j <= m->indep_count; j++) {
+            m->covariance[i][j] *= decay;
+            m->covariance[i][j] += var[i] * var[j];
+        }
+    }
+}
+
+void avpriv_solve_lls(LLSModel *m, double threshold, unsigned short min_order)
+{
+    int i, j, k;
+    double (*factor)[MAX_VARS + 1] = (void *) &m->covariance[1][0];
+    double (*covar) [MAX_VARS + 1] = (void *) &m->covariance[1][1];
+    double *covar_y                = m->covariance[0];
+    int count                      = m->indep_count;
+
+    for (i = 0; i < count; i++) {
+        for (j = i; j < count; j++) {
+            double sum = covar[i][j];
+
+            for (k = i - 1; k >= 0; k--)
+                sum -= factor[i][k] * factor[j][k];
+
+            if (i == j) {
+                if (sum < threshold)
+                    sum = 1.0;
+                factor[i][i] = sqrt(sum);
+            } else {
+                factor[j][i] = sum / factor[i][i];
+            }
+        }
+    }
+
+    for (i = 0; i < count; i++) {
+        double sum = covar_y[i + 1];
+
+        for (k = i - 1; k >= 0; k--)
+            sum -= factor[i][k] * m->coeff[0][k];
+
+        m->coeff[0][i] = sum / factor[i][i];
+    }
+
+    for (j = count - 1; j >= min_order; j--) {
+        for (i = j; i >= 0; i--) {
+            double sum = m->coeff[0][i];
+
+            for (k = i + 1; k <= j; k++)
+                sum -= factor[k][i] * m->coeff[j][k];
+
+            m->coeff[j][i] = sum / factor[i][i];
+        }
+
+        m->variance[j] = covar_y[0];
+
+        for (i = 0; i <= j; i++) {
+            double sum = m->coeff[j][i] * covar[i][i] - 2 * covar_y[i + 1];
+
+            for (k = 0; k < i; k++)
+                sum += 2 * m->coeff[j][k] * covar[k][i];
+
+            m->variance[j] += m->coeff[j][i] * sum;
+        }
+    }
+}
+
+double avpriv_evaluate_lls(LLSModel *m, double *param, int order)
+{
+    int i;
+    double out = 0;
+
+    for (i = 0; i <= order; i++)
+        out += param[i] * m->coeff[order][i];
+
+    return out;
+}
+
+#if FF_API_LLS_PRIVATE
+av_cold void av_init_lls(LLSModel *m, int indep_count)
+{
+    avpriv_init_lls(m, indep_count);
+}
+void av_update_lls(LLSModel *m, double *param, double decay)
+{
+    avpriv_update_lls(m, param, decay);
+}
+void av_solve_lls(LLSModel *m, double threshold, int min_order)
+{
+    avpriv_solve_lls(m, threshold, min_order);
+}
+double av_evaluate_lls(LLSModel *m, double *param, int order)
+{
+    return avpriv_evaluate_lls(m, param, order);
+}
+#endif /* FF_API_LLS_PRIVATE */
+
+#endif /* FF_API_LLS1 */
+
+#ifdef TEST
+
+#include <stdio.h>
+#include <limits.h>
+#include "lfg.h"
+
+int main(void)
+{
+    LLSModel m;
+    int i, order;
+    AVLFG lfg;
+
+    av_lfg_init(&lfg, 1);
+    avpriv_init_lls(&m, 3);
+
+    for (i = 0; i < 100; i++) {
+        double var[4];
+        double eval;
+
+        var[0] = (av_lfg_get(&lfg) / (double) UINT_MAX - 0.5) * 2;
+        var[1] = var[0] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
+        var[2] = var[1] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
+        var[3] = var[2] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
+        avpriv_update_lls(&m, var, 0.99);
+        avpriv_solve_lls(&m, 0.001, 0);
+        for (order = 0; order < 3; order++) {
+            eval = avpriv_evaluate_lls(&m, var + 1, order);
+            printf("real:%9f order:%d pred:%9f var:%f coeffs:%f %9f %9f\n",
+                   var[0], order, eval, sqrt(m.variance[order] / (i + 1)),
+                   m.coeff[order][0], m.coeff[order][1],
+                   m.coeff[order][2]);
+        }
+    }
+    return 0;
+}
+
+#endif
diff --git a/libavutil/lls1.h b/libavutil/lls1.h
new file mode 100644
index 0000000000..c785d44421
--- /dev/null
+++ b/libavutil/lls1.h
@@ -0,0 +1,54 @@
+/*
+ * linear least squares model
+ *
+ * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_LLS_H
+#define AVUTIL_LLS_H
+
+#include "version.h"
+
+#define MAX_VARS 32
+
+//FIXME avoid direct access to LLSModel from outside
+
+/**
+ * Linear least squares model.
+ */
+typedef struct LLSModel {
+    double covariance[MAX_VARS + 1][MAX_VARS + 1];
+    double coeff[MAX_VARS][MAX_VARS];
+    double variance[MAX_VARS];
+    int indep_count;
+} LLSModel;
+
+void avpriv_init_lls(LLSModel *m, int indep_count);
+void avpriv_update_lls(LLSModel *m, double *param, double decay);
+void avpriv_solve_lls(LLSModel *m, double threshold, unsigned short min_order);
+double avpriv_evaluate_lls(LLSModel *m, double *param, int order);
+
+#if FF_API_LLS_PRIVATE
+void av_init_lls(LLSModel *m, int indep_count);
+void av_update_lls(LLSModel *m, double *param, double decay);
+void av_solve_lls(LLSModel *m, double threshold, int min_order);
+double av_evaluate_lls(LLSModel *m, double *param, int order);
+#endif /* FF_API_LLS_PRIVATE */
+
+#endif /* AVUTIL_LLS_H */
diff --git a/libavutil/version.h b/libavutil/version.h
index b03aa4a871..369d8cc93a 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -132,6 +132,9 @@
 #ifndef FF_API_LLS_PRIVATE
 #define FF_API_LLS_PRIVATE              (LIBAVUTIL_VERSION_MAJOR < 53)
 #endif
+#ifndef FF_API_LLS1
+#define FF_API_LLS1                     (LIBAVUTIL_VERSION_MAJOR < 53)
+#endif
 #ifndef FF_API_AVFRAME_LAVC
 #define FF_API_AVFRAME_LAVC             (LIBAVUTIL_VERSION_MAJOR < 53)
 #endif