Book 1: Double vs Float more explanation

[D-K-E]

It would be nice to have a small overview of pros and cons of using double or float for the end of first book section 3.1. The difference became relevant as I was implementing the second book in cuda.

• double: more numerical precision
• double: twice the memory use compared to float
• float: less numerical precision.
• float: cuts down the memory use by half compared to double

When I tested the final scene of the second book, I got out of ressources error from cuda, but everything worked fine with float.
Though obvious it is, it might be important to mention that.