1 /* vm: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
2
3 /*
4 * gog-polynom-reg.c :
5 *
6 * Copyright (C) 2005 Jean Brefort (jean.brefort@normalesup.org)
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) version 3.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
21 * USA
22 */
23
24 #include <goffice/goffice-config.h>
25 #include "gog-polynom-reg.h"
26 #include <goffice/graph/gog-reg-curve.h>
27 #include <goffice/math/go-math.h>
28 #include <goffice/math/go-regression.h>
29 #include <glib/gi18n-lib.h>
30
31 #include <gsf/gsf-impl-utils.h>
32
33 #define UNICODE_MINUS_SIGN_C 0x2212
34 static int minus_utf8_len;
35 static char minus_utf8[6];
36
37 static GogObjectClass *gog_polynom_reg_curve_parent_klass;
38
39 static int
gog_polynom_reg_curve_build_values(GogLinRegCurve * rc,double const * x_vals,double const * y_vals,int n)40 gog_polynom_reg_curve_build_values (GogLinRegCurve *rc, double const *x_vals,
41 double const *y_vals, int n)
42 {
43 double x, y, xx;
44 double xmin, xmax;
45 int i, j, used;
46
47 gog_reg_curve_get_bounds (&rc->base, &xmin, &xmax);
48 if (rc->x_vals == NULL)
49 rc->x_vals = g_new0 (double*, rc->dims);
50 for (i = 0; i < rc->dims; i++) {
51 g_free (rc->x_vals[i]);
52 rc->x_vals[i] = g_new (double, n);
53 }
54 g_free (rc->y_vals);
55 rc->y_vals = g_new (double, n);
56 for (i = 0, used = 0; i < n; i++) {
57 x = (x_vals)? x_vals[i]: i + 1;
58 y = y_vals[i];
59 if (!go_finite (x) || !go_finite (y)) {
60 if (rc->base.skip_invalid)
61 continue;
62 used = 0;
63 break;
64 }
65 if (x < xmin || x > xmax)
66 continue;
67 xx = 1.;
68 for (j = 0; j < rc->dims; j++) {
69 xx *= x;
70 rc->x_vals[j][used] = xx;
71 }
72 rc->y_vals[used] = y;
73 used++;
74 }
75 return (used > rc->dims)? used: 0;
76 }
77
78 static double
gog_polynom_reg_curve_get_value_at(GogRegCurve * curve,double x)79 gog_polynom_reg_curve_get_value_at (GogRegCurve *curve, double x)
80 {
81 GogLinRegCurve *lin = GOG_LIN_REG_CURVE (curve);
82 double result = curve->a[0] + curve->a[1] * x, xx = x;
83 int i;
84 for (i = 1; i < lin->dims;) {
85 xx *= x;
86 i++;
87 result += xx * curve->a[i];
88 }
89 return result;
90 }
91
92 static const char *const exponent[10] = {
93 "\xE2\x81\xB0",
94 "\xC2\xB9",
95 "\xC2\xB2",
96 "\xC2\xB3",
97 "\xE2\x81\xB4",
98 "\xE2\x81\xB5",
99 "\xE2\x81\xB6",
100 "\xE2\x81\xB7",
101 "\xE2\x81\xB8",
102 "\xE2\x81\xB9"
103 };
104
105 /* Add an exponent, i.e., a super-scripted number. */
106 static void
append_exponent(GString * res,unsigned int i)107 append_exponent (GString *res, unsigned int i)
108 {
109 if (i >= 10) {
110 append_exponent (res, i / 10);
111 i %= 10;
112 }
113 g_string_append (res, exponent[i]);
114 }
115
116
117 static void
append_number(GString * res,double c,gboolean suppress1)118 append_number (GString *res, double c, gboolean suppress1)
119 {
120 size_t prelen = res->len;
121
122 g_string_append_printf (res, "%g", c);
123
124 if (suppress1 && res->len == prelen + 1 && res->str[prelen] == '1')
125 g_string_truncate (res, prelen);
126 else {
127 /* Handle the minuses as in -1.2222e-3. */
128 size_t i;
129 for (i = prelen; i < res->len; i++)
130 if (res->str[i] == '-') {
131 res->str[i] = minus_utf8[0];
132 g_string_insert_len (res, i + 1, minus_utf8 + 1, minus_utf8_len - 1);
133 i += minus_utf8_len - 1;
134 }
135 }
136 }
137
138
139 static gchar const*
gog_polynom_reg_curve_get_equation(GogRegCurve * curve)140 gog_polynom_reg_curve_get_equation (GogRegCurve *curve)
141 {
142 if (!curve->equation) {
143 GogLinRegCurve *lin = GOG_LIN_REG_CURVE (curve);
144 GString *str = g_string_new ("y =");
145 int i, lasti = (lin->affine ? 0 : 1), j = 0;
146
147 for (i = lin->dims; i >= lasti; i--) {
148 double c_i = curve->a[i];
149
150 if (c_i == 0.) /* a very rare event */
151 continue;
152
153 /* Break after every three terms present. */
154 if (j > 0 && j % 3 == 0)
155 g_string_append_c (str, '\n');
156 j++;
157
158 g_string_append_c (str, ' ');
159 if (j != 1) {
160 if (c_i >= 0)
161 g_string_append_c (str, '+');
162 else {
163 g_string_append_len (str, minus_utf8, minus_utf8_len);
164 c_i = -c_i;
165 }
166 g_string_append_c (str, ' ');
167 }
168
169 append_number (str, c_i, i >= 1);
170
171 if (i >= 1) {
172 g_string_append_c (str, 'x');
173 if (i > 1)
174 append_exponent (str, i);
175 }
176 }
177 if (j == 0) {
178 /* Nothing whatsoever. */
179 g_string_append (str, " 0");
180 }
181
182 curve->equation = g_string_free (str, FALSE);
183 }
184 return curve->equation;
185 }
186
187 #ifdef GOFFICE_WITH_GTK
188 #include <gtk/gtk.h>
189 static void
order_changed_cb(GtkSpinButton * btn,GObject * obj)190 order_changed_cb (GtkSpinButton *btn, GObject *obj)
191 {
192 g_object_set (obj, "dims", gtk_spin_button_get_value_as_int (btn), NULL);
193 }
194
195 static void
gog_polynom_reg_curve_populate_editor(GogRegCurve * reg_curve,gpointer table)196 gog_polynom_reg_curve_populate_editor (GogRegCurve *reg_curve, gpointer table)
197 {
198 GtkWidget *l, *w;
199 GogLinRegCurve *lin = GOG_LIN_REG_CURVE (reg_curve);
200
201 ((GogRegCurveClass*) gog_polynom_reg_curve_parent_klass)->populate_editor (reg_curve, table);
202 l = gtk_label_new (_("Order:"));
203 gtk_misc_set_alignment (GTK_MISC (l), 0., 0.5);
204 gtk_label_set_justify (GTK_LABEL (l), GTK_JUSTIFY_LEFT);
205 gtk_widget_show (l);
206 gtk_grid_attach_next_to (table, l, NULL, GTK_POS_BOTTOM, 1, 1);
207 w = gtk_spin_button_new_with_range (2, 10, 1);
208 gtk_spin_button_set_digits (GTK_SPIN_BUTTON (w), 0);
209 gtk_widget_show (w);
210 gtk_grid_attach_next_to (table, w, l, GTK_POS_RIGHT, 1, 1);
211 gtk_spin_button_set_value (GTK_SPIN_BUTTON (w), lin->dims);
212 g_signal_connect (G_OBJECT (w), "value-changed", G_CALLBACK (order_changed_cb), lin);
213 }
214 #endif
215
216 static char const *
gog_polynom_reg_curve_type_name(G_GNUC_UNUSED GogObject const * item)217 gog_polynom_reg_curve_type_name (G_GNUC_UNUSED GogObject const *item)
218 {
219 /* xgettext : the base for how to name scatter plot objects
220 * eg The 2nd plot in a chart will be called
221 * Polynomial regression2 */
222 return N_("Polynomial regression");
223 }
224
225 static void
gog_polynom_reg_curve_class_init(GogRegCurveClass * reg_curve_klass)226 gog_polynom_reg_curve_class_init (GogRegCurveClass *reg_curve_klass)
227 {
228 GogLinRegCurveClass *lin_reg_klass = (GogLinRegCurveClass *) reg_curve_klass;
229 GogObjectClass *gog_object_klass = (GogObjectClass *) reg_curve_klass;
230
231 gog_polynom_reg_curve_parent_klass = g_type_class_peek_parent (reg_curve_klass);
232
233 lin_reg_klass->build_values = gog_polynom_reg_curve_build_values;
234 lin_reg_klass->max_dims = 10;
235
236 reg_curve_klass->get_value_at = gog_polynom_reg_curve_get_value_at;
237 reg_curve_klass->get_equation = gog_polynom_reg_curve_get_equation;
238 #ifdef GOFFICE_WITH_GTK
239 reg_curve_klass->populate_editor = gog_polynom_reg_curve_populate_editor;
240 #endif
241
242 gog_object_klass->type_name = gog_polynom_reg_curve_type_name;
243
244 minus_utf8_len = g_unichar_to_utf8 (UNICODE_MINUS_SIGN_C, minus_utf8);
245 }
246
247 static void
gog_polynom_reg_curve_init(GogLinRegCurve * model)248 gog_polynom_reg_curve_init (GogLinRegCurve *model)
249 {
250 GogRegCurve *curve = GOG_REG_CURVE (model);
251 g_free (curve->a);
252 curve->a = g_new (double, 3);
253 curve->a[0] = curve->a[1] = curve->a[2] = go_nan;
254 model->dims = 2;
255 }
256
257 GSF_DYNAMIC_CLASS (GogPolynomRegCurve, gog_polynom_reg_curve,
258 gog_polynom_reg_curve_class_init, gog_polynom_reg_curve_init,
259 GOG_TYPE_LIN_REG_CURVE)
260