fptest-0.2.1.0: README.md

# IEEE754 conformance tests for Haskell

This project contains floating point conformance tests in Haskell.

There are two sets of tests so far:

##QTrial##
**QTrial** is the floating point benchmark described in *IEEE Standard 754 for Binary Floating-Point Arithmetic* by Prof. W. Kahan [Download link](http://www.eecs.berkeley.edu/~wkahan/ieee754status/IEEE754.PDF)

You should just be able to `cabal run` from the main directory or `runhaskell QTrial.hs` from `src`.

An extract from the result is:


```
Principal Tests:

Results for Float:
r = 4098.0 produces 12.0 and 12.0 sig. bits
r = 4098.25 fails: root 0.99989897 isn't at least 1
r = 4097.004 produces 12.0 and 11.999298 sig. bits
r =1.6777218e7 is too big for qtrail
r =1.6777218e7 is too big for qtrail
r =1.677722e7 is too big for qtrail
r =9.4906264e7 is too big for qtrail
r =9.4906264e7 is too big for qtrail
r =2.6843546e8 is too big for qtrail
r =2.6843546e8 is too big for qtrail
r =2.6843546e8 is too big for qtrail
r =2.6843546e8 is too big for qtrail
r =2.6843546e8 is too big for qtrail
r =4.2949673e9 is too big for qtrail
r =4.2949673e9 is too big for qtrail
Worst accuracy is 11.999298 sig. bits


Results for Double:
r = 4098.0 produces Infinity and Infinity sig. bits
r = 4098.25 produces Infinity and 53.0 sig. bits
r = 4097.00390625 produces Infinity and 53.451178091541244 sig. bits
r = 1.6777218e7 produces Infinity and Infinity sig. bits
r = 1.677721825e7 produces Infinity and 75.0 sig. bits
r = 1.6777219e7 produces Infinity and 71.0 sig. bits
r = 9.4906267e7 produces 26.499999994288153 and 26.499999986733027 sig. bits
r = 9.490626725e7 fails: root 0.999999995635551 isn't at least 1
r = 2.684354505e8 produces 28.0 and 27.999999919383132 sig. bits
r = 2.684354515e8 produces 28.0 and 27.99999993013205 sig. bits
r = 2.68435458e8 produces 28.0 and 28.0 sig. bits
r = 2.6843545825e8 produces 28.0 and 28.00000000268723 sig. bits
r = 2.6843545700000006e8 produces 28.0 and 27.999999989251084 sig. bits
r = 4.294967298e9 produces 32.0 and 32.0 sig. bits
r = 4.29496729825e9 produces 32.0 and 32.00000000016795 sig. bits
Worst accuracy is 26.499999986733027 sig. bits
```

This is fine for the Float cases, but the test illustrates an issue with the Double case.

##FPTest##

** FPTest is being refactored so that it can be run in cabal **

**FPTest** runs a sequence of floating point test vectors generated by IBM's [FPGen Floating-Point Test Generator](https://www.research.ibm.com/haifa/projects/verification/fpgen/).

This is done in two ways:

* By interpreting the tests
* By translating the tests into a Haskell HUnit test suite script that can just be run using `runhaskell`

The IBM test vectors are contained in the `test_suite` directory, but you will want to get the latest version from the link above.

You will, most likely, want the binary tests unless you have a decimal machine.  Only 32-bit float tests are provided (not 64-bit double ones).


The syntax of the test vectors can be found [here](https://www.research.ibm.com/haifa/projects/verification/fpgen/syntax.txt) or in Chapter 4 of [Floating-Point Test-Suite for IEEE](https://www.research.ibm.com/haifa/projects/verification/fpgen/papers/ieee-test-suite-v2.pdf)

The test suite that IBM supplies actually stretches the spec somewhat.  For example, it also uses lower case versions of some specification elements.