cspice_twovec |
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## AbstractCSPICE_calculates the transformation matrix to the right-handed reference frame having an input vector as a specified axis and a second input vector lying in a define coordinate plane. ## I/OGiven: axdef the principal axes of a coordinate frame. [3,1] = size(axdef); double = class(axdef) indexa the index signifying which of the three coordinate axes contains 'axdef' (1, 2 or 3). [1,1] = size(indexa); int32 = class(indexa) If 'indexa' is 1 then axdef defines the X axis of the coordinate frame. If 'indexa' is 2 then axdef defines the Y axis of the coordinate frame. If 'indexa' is 3 then axdef defines the Z axis of the coordinate frame. plndef a vector in the same plane as 'axdef'. 'axdef' and 'plndef' must be linearly independent. [3,1] = size(plndef); double = class(plndef) indexp the index signifying the second principle axis, orthogonal to 'axdef' (1, 2 or 3). [1,1] = size(indexp); int32 = class(indexp) If 'indexp' is 1, the second axis of the principal plane is the X-axis. If 'indexp' is 2, the second axis of the principal plane is the Y-axis. If 'indexp' is 3, the second axis of the principal plane is the Z-axis. the call: mout = ## ExamplesAny numerical results shown for this example may differ between platforms as the results depend on the SPICE kernels used as input and the machine specific arithmetic implementation. Example: % % A trivial example. Define the reference vectors... % % The i unit vector % axdef = [ 1.; 0; 0.]; indexa = 1 ; % % The -j unit vector. For this example, any vector % in the x-y plane linearly independent of 'axdef' % will suffice. % plndef = [ 0.; -1.; 0.]; indexp = 2; % % Calculate the transformation matrix. The new frame % has 'axdef' as axis 'indexa', with 'plndef' in the same % plane, the direction axis 'indexp' in that plane % and orthogonal to 'axdef'. A third direction vector % completes the right handed frame. % mout = ## ParticularsGiven two linearly independent vectors there is a unique right-handed coordinate frame having: axdef lying along the indexa axis. plndef lying in the axdef-indexp coordinate plane. This routine determines the transformation matrix that transforms from coordinates used to represent the input vectors to the the system determined by axdef and plndef. Thus a vector (x,y,z) in the input coordinate system will have coordinates t mout* (x,y,z) in the frame determined by axdef and plndef. ## Required ReadingFor important details concerning this module's function, please refer to the CSPICE routine twovec_c. MICE.REQ ## Version-Mice Version 1.0.1, 12-MAR-2015, EDW (JPL) Edited I/O section to conform to NAIF standard for Mice documentation. -Mice Version 1.0.0, 10-JAN-2006, EDW (JPL) ## Index_Entriesdefine an orthonormal frame from two vectors |

Wed Apr 5 18:00:36 2017