我下了一个求解逆矩阵的函数,运行发现全是零,大家帮忙看一下在哪里出错了。下面是我的代码#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>double b[9];
double a[9]={1,0,0,0,1,4,4,0,1};int gaus(double a[],double b[],int n) { int *js,l,k,i,j,is,p,q;
double d,t;
js=(int *)malloc(n*sizeof(int));
l=1;
for (k=0;k<=n-2;k++)
{ d=0.0;
for (i=k;i<=n-1;i++)
for (j=k;j<=n-1;j++)
{ t=fabs(a[i*n+j]);
if (t>d) { d=t; js[k]=j; is=i;}
}
if (d+1.0==1.0) l=0;
else
{ if (js[k]!=k)
for (i=0;i<=n-1;i++)
{ p=i*n+k; q=i*n+js[k];
t=a[p]; a[p]=a[q]; a[q]=t;
}
if (is!=k)
{ for (j=k;j<=n-1;j++)
{ p=k*n+j; q=is*n+j;
t=a[p]; a[p]=a[q]; a[q]=t;
}
t=b[k]; b[k]=b[is]; b[is]=t;
}
}
if (l==0)
{ free(js); printf("fail\n");
return(0);
}
d=a[k*n+k];
for (j=k+1;j<=n-1;j++)
{ p=k*n+j; a[p]=a[p]/d;}
b[k]=b[k]/d;
for (i=k+1;i<=n-1;i++)
{ for (j=k+1;j<=n-1;j++)
{ p=i*n+j;
a[p]=a[p]-a[i*n+k]*a[k*n+j];
}
b[i]=b[i]-a[i*n+k]*b[k];
}
}
d=a[(n-1)*n+n-1];
if (fabs(d)+1.0==1.0)
{ free(js); printf("fail\n");
return(0);
}
b[n-1]=b[n-1]/d;
for (i=n-2;i>=0;i--)
{ t=0.0;
for (j=i+1;j<=n-1;j++)
t=t+a[i*n+j]*b[j];
b[i]=b[i]-t;
}
js[n-1]=n-1;
for (k=n-1;k>=0;k--)
if (js[k]!=k)
{ t=b[k]; b[k]=b[js[k]]; b[js[k]]=t;}
free(js);
return(1);
}void main()
{
int i;
memset(b,0,9 * sizeof(double));
gaus(a,b,3);
for(i=1;i<10;i++)
{
printf("%d ",b[i-1]);
if((i%3)==0)
printf("\n");
}
}
#include <math.h>
#include <stdlib.h>
#include <string.h>double b[9];
double a[9]={1,0,0,0,1,4,4,0,1};int gaus(double a[],double b[],int n) { int *js,l,k,i,j,is,p,q;
double d,t;
js=(int *)malloc(n*sizeof(int));
l=1;
for (k=0;k<=n-2;k++)
{ d=0.0;
for (i=k;i<=n-1;i++)
for (j=k;j<=n-1;j++)
{ t=fabs(a[i*n+j]);
if (t>d) { d=t; js[k]=j; is=i;}
}
if (d+1.0==1.0) l=0;
else
{ if (js[k]!=k)
for (i=0;i<=n-1;i++)
{ p=i*n+k; q=i*n+js[k];
t=a[p]; a[p]=a[q]; a[q]=t;
}
if (is!=k)
{ for (j=k;j<=n-1;j++)
{ p=k*n+j; q=is*n+j;
t=a[p]; a[p]=a[q]; a[q]=t;
}
t=b[k]; b[k]=b[is]; b[is]=t;
}
}
if (l==0)
{ free(js); printf("fail\n");
return(0);
}
d=a[k*n+k];
for (j=k+1;j<=n-1;j++)
{ p=k*n+j; a[p]=a[p]/d;}
b[k]=b[k]/d;
for (i=k+1;i<=n-1;i++)
{ for (j=k+1;j<=n-1;j++)
{ p=i*n+j;
a[p]=a[p]-a[i*n+k]*a[k*n+j];
}
b[i]=b[i]-a[i*n+k]*b[k];
}
}
d=a[(n-1)*n+n-1];
if (fabs(d)+1.0==1.0)
{ free(js); printf("fail\n");
return(0);
}
b[n-1]=b[n-1]/d;
for (i=n-2;i>=0;i--)
{ t=0.0;
for (j=i+1;j<=n-1;j++)
t=t+a[i*n+j]*b[j];
b[i]=b[i]-t;
}
js[n-1]=n-1;
for (k=n-1;k>=0;k--)
if (js[k]!=k)
{ t=b[k]; b[k]=b[js[k]]; b[js[k]]=t;}
free(js);
return(1);
}void main()
{
int i;
memset(b,0,9 * sizeof(double));
gaus(a,b,3);
for(i=1;i<10;i++)
{
printf("%d ",b[i-1]);
if((i%3)==0)
printf("\n");
}
}
下面是我用C#写的~
using System;
using System.Collections.Generic;public class MyClass
{
public static void Main()
{
int [,] a = new int[4,4]{ {1,1,1,1},{2,2,2,2},{3,3,3,3},{4,4,4,4} };
//a={ 1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4 };
for (int i=0;i<4;i++)
{
for(int j=i+1;j<4;j++)
{
int temp;
temp=a[i,j];
a[i,j]=a[j,i];
a[j,i]=temp;
}
}
for(int i=0;i<4;i++)
{
for(int j=0;j<4;j++)
{
Console.Write("{0}",a[i,j]);
}
Console.WriteLine();
}
Console.ReadLine();
}
#region Helper methods private static void WL(object text, params object[] args)
{
Console.WriteLine(text.ToString(), args);
}
private static void RL()
{
Console.ReadLine();
}
private static void Break()
{
System.Diagnostics.Debugger.Break();
} #endregion
}