Designing Games with Game Maker - YoYo Games

andom_set_seed(seed) Sets the seed (an integer) that is used for the
random number generation. Can be used to repeat the same random
sequence. (Note though that also some actions and the system itself uses
random numbers.
random_get_seed() Returns the current seed.
randomize() Sets the seed to a random number.
choose(val1,val2,val3,...) Returns one of the arguments choosen
randomly. The function can have up to 16 arguments.
abs(x) Returns the absolute value of x.
sign(x) Returns the sign of x (-1, 0 or 1).
round(x) Returns x rounded to the nearest integer.
floor(x) Returns the floor of x, that is, x rounded down to an integer.
ceil(x) Returns the ceiling of x, that is, x rounded up to an integer.
frac(x) Returns the fractional part of x, that is, the part behind the decimal
dot.
sqrt(x) Returns the square root of x. x must be non-negative.
sqr(x) Returns x*x.
power(x,n) Returns x to the power n.
exp(x) Returns e to the power x.
ln(x) Returns the natural logarithm of x.
log2(x) Returns the log base 2 of x.
log10(x) Returns the log base 10 of x.
logn(n,x) Returns the log base n of x.
sin(x) Returns the sine of x (x in radians).
cos(x) Returns the cosine of x (x in radians).
tan(x) Returns the tangent of x (x in radians).
arcsin(x) Returns the inverse sine of x.
arccos(x) Returns the inverse cosine of x.
arctan(x) Returns the inverse tangent of x.
arctan2(y,x) Calculates arctan(Y/X), and returns an angle in the correct
quadrant.
degtorad(x) Converts degrees to radians.
radtodeg(x) Converts radians to degrees.
min(val1,val2,val3,...) Returns the minimum of the values. The
function can have up to 16 arguments. They must either be all real or all
strings.