/*
pA: the pointer of the Matrix A|b
rowMax,colMax:size of matirx
pX: solution vector
return value: -1 solving equation failed
1 resolve result successfully
*/
int gaussLesung(double *pA, int rowMax,int colMax, double *pX)
{
double *pMatrix = pA;
int i;
double product;
product = 1;
if((1+rowMax)!=colMax) return -1;
for(i = 0; i < rowMax; i++)
{
int l;
printf("%d,\n",i);
l = findMax(pMatrix, rowMax, colMax, i,i);
exchangeRow(pMatrix, rowMax, colMax, l, i);
eliminate(pMatrix, rowMax, colMax, i, i);
outputMatrix(pMatrix, rowMax, colMax);
}
for(i = 0; i < rowMax; i++)product = product * pMatrix[i*colMax+i];
if(product==0)return -1;
solveX(pMatrix, rowMax,colMax, pX);
return 1;
}
/*
input: A m x n matrix
output: A m x n matrix in reduced row echelon form.
*/
void rref(double **m, int row, int col){
double pivot;
int lead;
for(int i=0; i<row; i++){
lead = i; //lead will ALWAYS be >= i
pivot = m[i][lead];
//find a non-zero pivot in row
while(pivot == 0 && lead < col){
//perform exchange
if(exchangeRow(m, row, col, i)){
break;
}
else{
lead++; //new lead
pivot = m[i][lead]; //new pivot
}
}
if(lead < row) //reduce using row which has atleast 1 non-zero item
reduce(m, row, col, i, lead);
}
}