理学试验直接法求解线性方程组.pptx

试验3解线性方程组的直接法/*DirectMethodforSolvingLinearSystems*/求解§1高斯消元法/*GaussianElimination*/高斯消元法:思路首先将A化为上三角阵/*upper-triangularmatrix*/,再回代求解/*backwardsubstitution*/。=,b,=1:|P|<=TOL则停止,输出无解信息,#include<>#include<>#include<>#include<>#defineN4#defineEPS1e-5voidGuass(doubleA[][N+1]){inti,j,k=0,I,t;doublew=0,p,b;for(k=0;k<N-1;k++){/*选主元*/ p=A[k][k]; I=k; for(i=k+1;i<N;i++) if(fabs(A[i][k])>fabs(p)) {p=A[i][k]; I=i; }if(fabs(p)<EPS){printf("thenumberiserror!i=%d,k=%d\n",i,k);exit(0);}/*换行*/if(I!=k)for(j=0;j<N+1;j++){b=A[k][j];A[k][j]=A[I][j]; A[I][j]=b;}for(i=k+1;i<N;i++){/*行乘数*/A[i][k]=A[i][k]/A[k][k];for(j=k+1;j<N+1;j++)A[i][j]=A[i][j]-A[i][k]*A[k][j];}}/*输出变换后的矩阵*/printf("TheMatrix:\n");for(i=0;i<N;i++){for(j=0;j<N+1;j++)printf("A[%d][%d]=%",i,j,A[i][j]);printf("\n");}if(fabs(A[N-1][N-1])<