Vector and Point
GRAPES can use vectors and points without decomposing them to their components or coordinate.
Preliminaries
There is no distinction between a point and a vector: all the points can be regarded as position vectors.
GRAPES treats any ordered pair of two real numbers as a vector.
Example: (2, 3)
If two elementary objects are written in juxtaposition, GRAPES treats this as a displacement vector.
Example: if you write PQ in an expression, this means a vector PQ. This is same as Q - P.
You can input a vector expression directly without decomposing it into components.
Example: the middle point of B and C can be input as (B + C) / 2.
Vector operation
Addition, subtraction, inner product, and scalar product are available.
Function having vectors as a value (The followings are principal functions)
The function giving the middle point or the point dividing a segment a : b.
The function defining a rotation.
The function giving the intersection of two lines.
The function giving the center of circumcircle.
Real-valued function having vector as an argument (The followings are principal functions)
|P|: the length of the vector (input "[P]", i.e. it's same as the absolute value).
The value of determinant.
The function giving the measure of an angle.
User function and vector
The user function can have vector as a function value.
The user function can take vector as an argument.
Real-valued functions of a vector variable can be differenciated, integrated from a to b, or summed up (sigma) over a finite number of vectors. The indefinite integral of such a function is not defined.