1 /* $NetBSD: mra.c,v 1.1 2004/05/28 17:52:06 tsarna 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 REGENTS 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 REGENTS 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 1.1 2004/05/28 17:52:06 tsarna Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 36 int mra_Y_AX1_BX2_C(int *, int, int *, int, int *, int, int, int, int *, 37 int *, int *); 38 39 /* 40 * multiple regression analysis 41 * Y = AX1 + BX2 + C 42 */ 43 int 44 mra_Y_AX1_BX2_C(int *y, int ys, int *x1, int x1s, int *x2, int x2s, int n, 45 int scale, int *a, int *b, int *c) 46 { 47 int i; 48 int64_t X1a, X2a, Ya; 49 int64_t X1X1s, X2X2s, X1X2s; 50 int64_t YYs, X1Ys, X2Ys; 51 int64_t S11, S22, S12; 52 int64_t SYY, S1Y, S2Y; 53 int64_t A, B, C, M; 54 #define AA(p, s, i) (*((long*)(((char*)(p)) + (s) * (i)))) 55 #define X1(i) AA(x1, x1s, i) 56 #define X2(i) AA(x2, x2s, i) 57 #define Y(i) AA(y, ys, i) 58 59 /* 60 * get avarage and sum 61 */ 62 X1a = 0; X2a = 0; Ya = 0; 63 X1X1s = 0; X2X2s = 0; X1X2s = 0; 64 X1Ys = 0; X2Ys = 0; YYs = 0; 65 for (i = 0; i < n; i++) { 66 X1a += X1(i); 67 X2a += X2(i); 68 Ya += Y(i); 69 70 X1X1s += X1(i) * X1(i); 71 X2X2s += X2(i) * X2(i); 72 X1X2s += X1(i) * X2(i); 73 74 X1Ys += X1(i) * Y(i); 75 X2Ys += X2(i) * Y(i); 76 YYs += Y(i) * Y(i); 77 } 78 X1a /= n; X2a /= n; Ya /= n; 79 80 S11 = X1X1s - n * X1a * X1a; 81 S22 = X2X2s - n * X2a * X2a; 82 S12 = X1X2s - n * X1a * X2a; 83 84 SYY = YYs - n * Ya * Ya; 85 S1Y = X1Ys - n * X1a * Ya; 86 S2Y = X2Ys - n * X2a * Ya; 87 88 #if 0 89 printf("X1a=%d X2a=%d Ya=%d\n", (int)X1a, (int)X2a, (int)Ya); 90 printf("X1X1s=%d X2X2s=%d X1X2s=%d\n", (int)X1X1s, (int)X2X2s, (int)X1X2s); 91 printf("X1Ys=%d X2Ys=%d YYs=%d\n", (int)X1Ys, (int)X2Ys, (int)YYs); 92 printf("S11=%d S22=%d S12=%d\n", (int)S11, (int)S22, (int)S12); 93 printf("SYY=%d S1Y=%d S2Y=%d\n", (int)SYY, (int)S1Y, (int)S2Y); 94 #endif 95 96 M = (S11 * S22 - S12 * S12); 97 if (M == 0) { 98 /* error */ 99 return -1; 100 } 101 102 A = (S1Y * S22 - S2Y * S12) * scale / M; 103 B = (S2Y * S11 - S1Y * S12) * scale / M; 104 C = Ya - (A * X1a + B * X2a) / scale; 105 106 #if 0 107 printf("A=%d B=%d C=%d\n", (int)A, (int)B, (int)C); 108 #endif 109 *a = A; 110 *b = B; 111 *c = C; 112 113 return (0); 114 } 115