double * multipleLinearRegression(double **X, double *y, int n, int m){
double **A, **XT, **B, *b, *x, **Y;
/* int i,j; */
Y=vectorToMatrix(y,m,1);
x=allocateDoubleVector(n);
XT=trasposeMatrix(X,n,m);
/* XT.X.x = XT.b */
A=multiplyMatrix(XT,X,m,n,n);
B=multiplyMatrix(XT,Y,m,n,1);
b=matrixToVector(B,n,1);
/* for (i=0; i<n; i++){
for (j=0; j<n; j++){
fprintf(stdout,"%f ",A[i][j]);
}
fprintf(stdout,"\n");
}
for(i=0;i<n;i++) fprintf(stdout,"%f ",b[i]);
fprintf(stdout,"\n"); */
x = gaussianElimination (n, A, b);
return x;
}
void transpose (Real **b, int size, int *len, int *disp, int rank, int m){
int i, *sendcounts, *rdispls;
Real *sendbuf, *recvbuf;
sendbuf = createRealArray (m * len[rank]);
recvbuf = createRealArray (m * len[rank]);
sendcounts = calloc(size,sizeof(int));
rdispls = calloc(size,sizeof(int));
matrixToVector(b,sendbuf,len,disp, size, rank);
int index = 0;
for (int i = 0; i < size; ++i)
{
sendcounts[i]= len[rank]*len[i];
rdispls[i]=index;
index=index+sendcounts[i];
}
MPI_Alltoallv(sendbuf, sendcounts, rdispls, MPI_DOUBLE, recvbuf, sendcounts, rdispls, MPI_DOUBLE, MPI_COMM_WORLD);
vectorToMatrix(b,recvbuf,len,disp, size, rank);
}
