Algorithmic Solutions > LEDA > LEDA Guide > Number Types > Floating Point Filter

## Floating Point Filter

The data type floatf provides a clean and efficient way to compute approximately with large integers.

Floating Point Filter encapsulates the conversion of operands to double and uses floating point arithmetic for computation. A `floatf` is represented by a double (its value) and an error bound. An operation on Floating Point Filter performs the operation on the values and also computes the error bound for the result.

### Strengths

• computes an error bound for the result of a computation
• more efficient than arbitrary precision integer arithmetic
• special function `Sign(x)` that computes the sign of x as +/-1, 0 or NO_IDEA. If Sign(x)!=NO_IDEA, the sign is guaranteed to be correct

• about 4 times slower than corresponding operations on doubles

### Tips

Use Floating Point Filter to speed up your computations with large integers, and recompute with `integer` if the result is not unique.

Integers of Arbitrary Length

Algebraic Real Numbers

Rational Numbers

Interval Arithmetic

Vectors and Matrices with Integer Entries

Vectors and Matrices with Double Entries

Rational Vectors

Functions of numerical analysis

Manual Page Floating Point Filter