Sgn is short for sign. Sgn is defined as follows:
x & gt0，sgnx= 1 .
x=0，sgnx=0 .
If the number of return values is greater than 0, Sgn returns 1, which is equal to 0; If it is less than 0, the sign of the-1 parameter determines the return value of the Sgn function, that is, x>0, sgnx= 1, x=0, sgnx=0.
Advanced mathematics:
Higher mathematics refers to a more complicated part of mathematical objects and methods compared with elementary mathematics and secondary mathematics. Algebra, geometry and simple set theory in middle school are called middle school mathematics, which is regarded as the transition between elementary mathematics in primary and secondary schools and higher mathematics in universities.
Generally speaking, advanced mathematics is a basic subject formed by calculus, algebra, geometry and their intersection. The main contents include: series, limit, calculus, spatial analytic geometry and linear algebra, series, ordinary differential equations. Basic subjects for postgraduate examinations in engineering, science and engineering and finance.
Refer to the above content: Baidu Encyclopedia-Advanced Mathematics