A double is an IEEE754 double-precision floating point number, similar to a float but with a larger range and precision. IEEE754 single precision numbers have 32 bits (1 sign, 8 exponent and 23 mantissa bits) while double precision numbers have 64 bits (1 sign, 11 exponent and 52 mantissa bits).
The heart muscle, like every other organ or tissue in your body, needs oxygen-rich blood to survive. Blood is supplied to the heart by its own vascular system, called coronary circulation. The aorta (the main blood supplier to the body) branches off into two main coronary blood vessels (also called arteries). These coronary arteries branch off into smaller arteries, which supply oxygen-rich blood to the entire heart muscle. The right coronary artery supplies blood mainly to the right side of the heart.
The arteries are major blood vessels connected to your heart. 1  The pulmonary artery carries blood from the right side of the heart to the lungs to pick up a fresh supply of oxygen. 2  The aorta is the main artery that carries oxygen-rich blood from the left side of the heart to the body. The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function.