Need help naming a class that represents a value and its linear variation

Question

When doing some refactoring, I found that I often use a pair or float to represent the initial value and how much this value changes linearly over time. I want to create a structure to hold both fields, but I just cannot find the correct name for it.

It should look something like this:

struct XXX
{
    float Value;
    float Slope; // or Delta? or Variation? 
}

Any suggestions would be highly appreciated.

Answer 1

Since you have an initial value and a value indicating how “something” evolves, you can go with something like “Linear function”.

I would also add the necessary member functions:

struct LinearFunction {
    float constant;
    float slope;
    float increment( float delta ) const { return constant + delta*slope; }
    void add( const LinearFunction& other ) { constant += other.constant; slope += other.slope; }
    LinearFunction invert() const { 
        LinearFunction inv = { -constant/slope, 1./slope; };
        return inv;
    }
};

Or do I want here?

Answer 2

, :

struct ValueDeltaDuplet
{
    float Value;
    float Delta;    
}

Answer 3

+ : ?

Answer 4

I like "Scale" ...

struct ValueScale
{
    float Value;
    float Slope;
}

or maybe

struct ScalableValue
{
    float Value;
    float Slope;
}

Answer 5

It's like an arithmetic progression (or arithmetic sequence)

struct sequence_num_t {
    float value;
    float delta;
};

or

struct SequencePoint
{
   float Value;
   float Delta;
};

Answer 6

struct ValueSlopePair
{
    float Value;
    float Slope;    
}

Answer 7

struct FloatPair
{
    float Value;
    float Slope;    
}