title: Python float precision float
body: <p>I need to implement a Dynamic Programming algorithm to solve the Traveling Salesman problem in time that beats Brute Force Search for computing distances between points. For this I need to index subproblems by size and the value of each subproblem will be a float (the length of the tour). However holding the array in memory will take about 6GB RAM if I use python floats (which actually have double precision) and so to try and halve that amount (I only have 4GB RAM) I will need to use single precision floats. However I do not know how I can get single precision floats in Python (I am using Python 3). Could someone please tell me where I can find them (I was not able to find much on this on the internet). Thanks.</p>
  
  <p><strong>EDIT</strong>: I notice that numpy also has a float16 type which will allow for even more memory savings. The distances between points are around 10000 and there are 25 unique points and my answer needs to be to the nearest integer. Will float16 provide enought accuracy or do I need to use float32?</p>