MAL.DeterminantTM

ref_arr_out = MAL.DeterminantTM( BYREF arr_out      AS ARRAY,

                                 BYREF arr_TM       AS ARRAY,

                                [BYVAL nFrameOffset AS INTEGER=0] ) AS REFERENCE

determinant = MAL.DeterminantTM( BYREF arr_TM       AS ARRAY ) AS REAL

Calculates the Detrminant of a 3x3 Transformation Matrix.  The determinant is a scalar value that is a function of the entries of a square matrix. It allows characterizing some properties of the matrix and the linear map represented by the matrix.

In the first syntax, the input is an array of a 3x3 matrix and should be declared as

DIM tm( nFrames, 3, 3 ) AS REAL

The output is a 1D array.

In the second syntax, the input matrix is a simepl 3x3 matrix declared as

DIM tm( 3, 3 ) AS REAL

The output is the determinant of the TM

Example:

OPTION EXPLICIT ON

OPTION REDIM ON

OPTION BASE 1

' Include C3D Support

$INCLUDE "MyBASIC2_C3DFile"

$LIBRARY "MyBASIC2_C3DFileLib"

' Needed to extract and Display Version

$LIBRARY "MyBASIC2_ExtLib"

' Include the MaxMAL Library

$INCLUDE "MyBASIC2_MaxMAL"

$LIBRARY "MyBASIC2_MaxMALLib"

' Forward Declare PrintArray and DisplayVersion

DECLARE SUB PrintArray

DECLARE SUB DisplayVersion

' Declare variables and arrays

DIM nPoints AS INTEGER

DIM nFrames AS INTEGER

DIM hFile   AS INTEGER

' Open the Test File

hFile = C3DFile.Open( "e:\Wander9.c3d" )

IF NOT hFile > 0 THEN

  PRINT "Error Opening File ";cFileName,

  STOP

ENDIF

' Get the no of points and frames

nFrames = C3DFile.GetNoOfFrames( hFile )

nPoints = C3DFile.GetNoOfPoints( hFile )

' Dimension the arrays

DIM Position(nFrames,nPoints,3)    AS REAL

' Get the Point Coordinates from C3D file

IF C3DFile.GetPoints( hFile, Position ) <> nFrames THEN

  C3DFile.Close( hFile )

  PRINT "Error Reading ";nPoints;" from file ";cFileName,

  STOP

ENDIF

' Set the Frame Rate to use in the MaxMAL Library

MAL.FrameRate( C3DFile.GetFrameRate( hFile ) )

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' Init TM as a 1D array

DIM tm( 9 ) AS REAL

tm( 1 ) = 7

tm( 2 ) = 1

tm( 3 ) = 3

tm( 4 ) = 2

tm( 5 ) = 4

tm( 6 ) = 1

tm( 7 ) = 1

tm( 8 ) = 5

tm( 9 ) = 1

' Now redimension it to a 3x3 TM

DIM tm( 3, 3 ) AS REAL

' Result should be 10 !

PRINT "Determinant:       ";MAL.DeterminantTM( tm ),

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' Init TM as a 1D array

DIM tm( 4, 9 ) AS REAL

tm( *, 1 ) = 7

tm( *, 2 ) = 1

tm( *, 3 ) = 3

tm( *, 4 ) = 2

tm( *, 5 ) = 4

tm( *, 6 ) = 1

tm( *, 7 ) = 1

tm( *, 8 ) = 5

tm( *, 9 ) = 1

' Now redimension it to a 3x3 TM

DIM tm( 4, 3, 3 ) AS REAL

CALL PrintArray( REF( tm ) )

DIM Determinant( 4, 1, 1 ) AS REAL

CALL PrintArray( MAL.DeterminantTM( Determinant, tm ) )

' Close File

C3DFile.Close( hFile )

END

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' Print an array with up to 3 dimensions.  Array is passed as a reference

'

SUB PrintArray( arr AS REFERENCE )

  RUN( "ArrayTable", arr, TRUE )

END SUB