# NAME

Math::VarRate - deal with linear, variable rates of increase

# VERSION

version 0.100000

# DESCRIPTION

Math::VarRate is a very, very poor man's calculus. A Math::VarRate object represents an accumulator that increases at a varying rate over time. The rate may change, it is always a linear, positive rate of change.

You can imagine the rate as representing "units gained per time." You can then interrogate the Math::VarRate object for the total units accumulated at any given offset in time, or for the time at which a given number of units will have first been accumulated.

# METHODS

## new

` my $varrate = Math::VarRate->new(\%arg);`

Valid arguments to `new`

are:

```
rate_changes - a hashref in which keys are offsets and values are rates
starting_value - the value at offset 0 (defaults to 0)
```

## starting_value

This method returns the value of the accumulator at offset 0.

## offset_for

` my $offset = $varrate->offset_for($value);`

This method returns the offset (positive, from 0) at which the given value is reached. If the given value will never be reached, undef will be returned.

## value_at

` my $value = $varrate->value_at($offset);`

This returns the value in the accumulator at the given offset.

# AUTHOR

Ricardo SIGNES <rjbs@cpan.org>

# COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Ricardo SIGNES.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.