I've been puzzled by the speed of MTL, please help me!

Dear sirs:
I've done some test on the speed of mtl, comparing to my c code. 
unfortunately, my mtl code runs more slowly than my c code. I'm sure I have 
misused the mtl library, but, I cannot overcome it. please give some guide.
my tests is about the speed of "Multiply matrix A times vector x", my 
compiler is visual c++ 6.0, I've compiled the code to be release version, so 
I think I've enable the option of optimisition.

I present some of my code below:
1)the mtl code:
typedef matrix< double,
              rectangle<>,
              dense<>,
              row_major>::type Matrix;
typedef dense1D<double> Vector;

const int M=1000;
const int N=1000;

void mtl_mult_vec()
{
	Matrix A(M, N);
	Vector B(N), C(M);

	for(int i=0;i<M;i++)
		for(int j=0;j<N;j++)
		{
			A(i,j) = i*N+j;
		}
	for(i=0;i<N;i++)
	{
			B[i] = i;
	}

//I'm desired in the running time of "mult"
	mult(A, B, C);
}

2)my c code

const int M=1000;
const int N=1000;
double 	A[M][N], B[N], C[M];

void c_mult_vec()
{
	for(int i=0;i<M;i++)
		for(int j=0;j<N;j++)
		{
			A[i][j] = i*N+j;
		}
	for(i=0;i<N;i++)
		{
			B[i] = i;
		}

//I'm desired in the running time of the code following.
	for(i=0;i<M;i++)
		for(int k=0;k<N;k++)
			C[i]+=A[i][k]*B[k];
}

according to my test, the running time of the two senarios is as following:
mtl      438ms
c code   63ms

I don't know why the speed of mtl is so slow, please give me some advice.


sincerely yours
hartor
2003.6.4

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