How should I find out what the default value of Accuracy and Precision is in the NDSolve? I have a pde that when I asked it to solve for me the equation with a special Accuracy and precision it gave me back an error, but if I live the NDSolve with its default. It would solve it. I don't know how to find the value of accuracy and precision. another basic question which have is about the meaning of the Accuracy and precision. I know the meaning in general from high school, but the problem is that I do not know the meaning of Accuracy->15, does it calculate it for 15 decimal number or what?
Following @Nasser's comment, both defaults are
$MachinePrecision/2, 7.97729 in my case.