Math with XYZWPR variables in Karel?

  • Hey guys, I am having some trouble doing math with XYZWPR variables.

    I have two XYZWPR variables, say pos1 and pos2.

    At first I tried to subtract them and get the result into a 3rd XYZWPR variable like so:

    pos1, pos2, pos3: XYZWPR
    pos3 = pos2 - pos1

    But I got an error saying:

    Operator expected POSITION data type for left operand.

    Any idea how to properly do math with that datatype?

  • Code
    pos1, pos2,pos3 : XYZWPR 
    pos4: POSITION
     pos4 = pos2 : INV(pos1)
     pos3 = pos4

    The robot in most times does automatic conversions between XYZWPR and POSITION.


    Is it possible to access fields of POSITION data just like XYZWPR?

    I have initialized

    uframe, utool : POSITION

    and gett the following error.

    What is the correct syntax to access fields of this position variable? This works for an XYZWPR

  • Hi,

    Just to confirm,

    Does the orient field contain the roll, pitch, and yaw values? and Location field just contains XYZ values?

    No. This is a matrix representation of the point. The location vector just contains XYZ values, but if you're looking for WPR representation you'll need to convert your position into XYZWPREXT. I believe that karel automatically converts between the data types, so you should be able to declare a new variable as XYZWPREXT and then assign it your position value. Something like this:

    uframe : position

    uframe2 : XYZWPREXT





    uframe2 = uframe


    I haven't tested this but from what I've read it should work.

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