fields tests: Testing fields functions

Description

Some of the basic methods in feilds can be tested by directly implementing the linear algebra using matrix expressions. These comparisons are done in the the R source code test files in the tests subdirectory of fields. The function test.for.zero is useful for comparing the tests in a meaninful and documented way.

Usage

test.for.zero( xtest,xtrue,  tol= 1.0e-8, relative=TRUE, tag=NULL)

Arguments

Details

The scripts in the tests subdirectory are

[object Object],[object Object],[object Object],[object Object],[object Object]

To run the tests just attach the fields library and source the testing file. In the the fields source code these are in a subdirectory "tests".

test.for.zero is used to print out the result for each individual comparison. Failed tests are potentially very bad and are reported with a string beginning

"FAILED test value = ... "

If the object test.for.zero.flag exists ( it can have any value), all the tests that pass print text beginning,

" PASSED test at tolerance ..."

This startegy means that if all tests succeed nothing and the object test.for.zero.flag does not exist then nothing is printed in the test scripts. This is option simplifies the output scripts for running through the tests -- no news is good news.

FORM OF COMPARISON: The actual test done is the sum of absolute differnces:

test value = sum( abs(c(xtest) - c( xtrue) ) ) /denom

Where demon is either mean( abs(c(xtrue))) for relative error or 1.0 otherwise.

Note the use of "c" here to stack any structure in xtest and xtrue into a vector.