1 /* $NetBSD: mra.c,v 1.4 2006/10/09 10:43:01 peter Exp $ */ 2 3 /* 4 * Copyright (c) 1999 Shin Takemura All rights reserved. 5 * Copyright (c) 1999 PocketBSD Project. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 */ 29 30 #include <sys/cdefs.h> 31 __KERNEL_RCSID(0, "$NetBSD: mra.c,v 1.4 2006/10/09 10:43:01 peter Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 36 extern int mra_Y_AX1_BX2_C(const int *, int, 37 const int *, int, const int *, int, int, int, 38 int *, int *, int *); 39 40 /* 41 * multiple regression analysis 42 * Y = AX1 + BX2 + C 43 */ 44 int 45 mra_Y_AX1_BX2_C(const int *y, int ys, 46 const int *x1, int x1s, const int *x2, int x2s, 47 int n, int scale, 48 int *a, int *b, int *c) 49 { 50 int i; 51 int64_t X1a, X2a, Ya; 52 int64_t X1X1s, X2X2s, X1X2s; 53 int64_t YYs, X1Ys, X2Ys; 54 int64_t S11, S22, S12; 55 int64_t SYY, S1Y, S2Y; 56 int64_t A, B, C, M; 57 #define AA(p, s, i) (*((const long *)(((const char *)(p)) + (s) * (i)))) 58 #define X1(i) AA(x1, x1s, i) 59 #define X2(i) AA(x2, x2s, i) 60 #define Y(i) AA(y, ys, i) 61 62 /* 63 * get avarage and sum 64 */ 65 X1a = 0; X2a = 0; Ya = 0; 66 X1X1s = 0; X2X2s = 0; X1X2s = 0; 67 X1Ys = 0; X2Ys = 0; YYs = 0; 68 for (i = 0; i < n; i++) { 69 X1a += X1(i); 70 X2a += X2(i); 71 Ya += Y(i); 72 73 X1X1s += X1(i) * X1(i); 74 X2X2s += X2(i) * X2(i); 75 X1X2s += X1(i) * X2(i); 76 77 X1Ys += X1(i) * Y(i); 78 X2Ys += X2(i) * Y(i); 79 YYs += Y(i) * Y(i); 80 } 81 X1a /= n; X2a /= n; Ya /= n; 82 83 S11 = X1X1s - n * X1a * X1a; 84 S22 = X2X2s - n * X2a * X2a; 85 S12 = X1X2s - n * X1a * X2a; 86 87 SYY = YYs - n * Ya * Ya; 88 S1Y = X1Ys - n * X1a * Ya; 89 S2Y = X2Ys - n * X2a * Ya; 90 91 #if 0 92 printf("X1a=%d X2a=%d Ya=%d\n", (int)X1a, (int)X2a, (int)Ya); 93 printf("X1X1s=%d X2X2s=%d X1X2s=%d\n", (int)X1X1s, (int)X2X2s, (int)X1X2s); 94 printf("X1Ys=%d X2Ys=%d YYs=%d\n", (int)X1Ys, (int)X2Ys, (int)YYs); 95 printf("S11=%d S22=%d S12=%d\n", (int)S11, (int)S22, (int)S12); 96 printf("SYY=%d S1Y=%d S2Y=%d\n", (int)SYY, (int)S1Y, (int)S2Y); 97 #endif 98 99 M = (S11 * S22 - S12 * S12); 100 if (M == 0) { 101 /* error */ 102 return -1; 103 } 104 105 A = (S1Y * S22 - S2Y * S12) * scale / M; 106 B = (S2Y * S11 - S1Y * S12) * scale / M; 107 C = Ya - (A * X1a + B * X2a) / scale; 108 109 #if 0 110 printf("A=%d B=%d C=%d\n", (int)A, (int)B, (int)C); 111 #endif 112 *a = A; 113 *b = B; 114 *c = C; 115 116 return (0); 117 } 118