average_sd.c

来自「vc的源代码程序的基于最小特征向量的元素的集合方法的程序源代码」· C语言 代码 · 共 105 行

/*************************************************************************/
/*                                                                       */
/*        Average results for training and test sets                     */
/*         and gives the standard deviation                              */
/*        ------------------------------------------                     */
/*                                                                       */
/*        This is a generic program that averages any numbers found on   */
/*        a set of lines of the same pattern.                            */
/*                                                                       */
/*************************************************************************/


#include <stdio.h>
#include <stdlib.h>

#define MAXLINE    200        /* max line length */
#define MAXVALS    10        /* max values to be averaged */

float value[2][MAXLINE/2][MAXVALS];

float sqr(float v)
{
	return v*v;
}

double std(int N, int col, int TrainTest, float mean)
{
	float var = 0;
	int i;
	for(i = 0; i<N; i++)
		var += sqr(value[TrainTest][i][col]);

	/* calculate the most efficient estimator */
	if(N>1) return sqrt((var-(float)N*sqr(mean))/(N-1));
	return 0;
}

main()
{
	char Line[MAXLINE], *p1, *p2;
	int Numbers=0, Lines=0, i, TrainTest;
	float Val, Sum[2][MAXVALS]; 
	float var, /* variance */
		mean; /* mean value */
	double strtod();

	for ( i = 0 ; i < MAXVALS ; i++ )
		Sum[0][i] = Sum[1][i] = 0;

	while ( fgets(Line, MAXLINE, stdin) )
	{
		int vLines = Lines / 2;
		i = 0;
		TrainTest = Lines % 2;

		/*  Count the numbers appearing on the line  */

		for ( p1 = Line ; *p1 != '\n' ; p1++ )
		{
			if ( *p1 < '0' || *p1 > '9' ) continue;

			Val = strtod(p1, &p2);
			value[TrainTest][vLines][i] = Val; 
/*			printf("%g ", value[TrainTest][vLines][i]);*/
			Sum[TrainTest][i++] += Val;
			p1 = p2-1;
		}

		/*  The number of numbers must match any previous lines  */

		printf("%s", Line);
		if ( Lines )
		{
			if ( i != Numbers ) exit(1);
		}
		else
			Numbers = i;
		Lines++;
	}

	putchar('\n');
	for ( TrainTest = 0 ; TrainTest <= 1 ; TrainTest++ )
	{
		i = 0;
/*		printf("%s:\t", TrainTest ? "test" : "train");*/

		for ( p1 = Line ; *p1 != '\n' ; p1++ )
		{
			if ( *p1 < '0' || *p1 > '9' )
			{
				putchar(*p1);
			}
			else
			{
				mean = Sum[TrainTest][i] * 2 / Lines;
				var = std(Lines/2, i++, TrainTest, mean);
				printf("%.1f+-%.1f", mean, var);
				strtod(p1, &p2);
				p1 = p2-1;
			}
		}
		putchar('\n');
	}
}