How to access pixel values of CV_32F/CV_64F Mat?

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I was working on homography and whenever I try to check the values of H matrix (type CV_64F) using H.at<float>(i, j) I get random numbers(sometimes garbage value). I want to access pixel values of float matrix. Is there any way to do it?

Mat A = Mat::eye(3, 3, CV_64F);
float B;
for(int i=0; i<A.rows; i++)
{
    for(int j=0; j<A.cols; j++)
    {
        printf("%f\n", A.at<float>(i, j));
    }
}

imshow("identity", A);
waitKey(0);

This shows correct image of an identity matrix but while trying to access pixel values, I get

0.000000 1.875000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000

Why is this so?