Adk44: Created page with "==Introduction== The GMIN SANITY module is intended to contain basic sanity check functions which can be used to help us check that we aren't doing anything stupid - for e..."

2019-05-10T17:22:50Z

Created page with "==Introduction== The GMIN SANITY module is intended to contain basic sanity check functions which can be used to help us check that we aren't doing anything stupid - for e..."

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==Introduction==
The [[GMIN]] SANITY module is intended to contain basic sanity check functions which can be used to help us check that we aren't doing anything stupid - for example trying to make a Cartesian displacement in an angle-axis system. You can find it here:

<pre>
~/svn/GMIN/source/sanity.f90
</pre>

It contains functions which return .TRUE. if the test is passed, and as a result should be called as follows:

<pre>
! Sanity check - are the coordinates in XYZ Cartesian?
! Check if the SIZE is a multiple of 3
TEST=.FALSE.
TEST=CHECK_DIMENSION(SIZE(XYZ),3)
IF (.NOT.TEST) THEN
STOP 'Coordinates in a non-Cartesian basis passed to ROTATION_ABOUT_AXIS'
ENDIF
</pre>

In this way, we can print helpful error messages from the routines where the check fails to aid in debugging problems, without having to recode the entire check each time.

==Coding principles==
[[Image:Coding.jpg|thumb|A useful way of thinking while coding|400px|right]]

In order to make these checks as easy to use as possible, you must adhere to a few basic coding principles when adding such checks

* all check functions must return .TRUE. if the check is passed
* code blocks must be indented in a manner consistent with the rest of the module (3 spaces)
* variable names must be understandable e.g. MAX_STEP rather than S
* avoid using GOTOs!
* all functions must be fully commented (in English)
* all arguments must be fully explained
* check functions should NOT print anything - printing should come from where the function is called. See the example call above - printing is done within the STOP command if the check fails.

==Example: CHECK_DIMENSION==
The call above comes from the [[GMIN MOVES module]]. We are using CHECK_DIMENSION to make sure that the coordinate array XYZ being used for moves assuming a Cartesian basis are indeed Cartesian:

<pre>
FUNCTION CHECK_DIMENSION(ARRAYSIZE, EXPECTED)
! Function to check the dimension of the ARRAY passed in.
! Returns .TRUE. if the dimension is as EXPECTED.
!
! Arguments:
!
! ARRAYSIZE: The size of the array to be checked
! EXPECTED: The expected dimension of the ARRAY
IMPLICIT NONE
INTEGER, INTENT(IN) :: EXPECTED
INTEGER, INTENT(IN) :: ARRAYSIZE
LOGICAL :: CHECK_DIMENSION

CHECK_DIMENSION=.FALSE.

IF (MODULO(ARRAYSIZE, EXPECTED) == 0) THEN
CHECK_DIMENSION=.TRUE.
ENDIF
END FUNCTION
</pre>

--[[User:Csw34|Csw34]] 17:25, 14 April 2014 (UTC)

GMIN SANITY module - Revision history

Adk44: Created page with "==Introduction== The GMIN SANITY module is intended to contain basic sanity check functions which can be used to help us check that we aren't doing anything stupid - for e..."