Mercurial > hg > orthanc-stone
view Resources/Computations/ComputeShearParameters.py @ 1113:3924ddbbadda
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author | Alain Mazy <alain@mazy.be> |
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date | Mon, 04 Nov 2019 12:47:13 +0100 |
parents | 46cb2eedc2e0 |
children |
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#!/usr/bin/python from sympy import * import pprint init_printing(use_unicode=True) s13, s23, s43 = symbols('s13 s23 s43') x, y, z, w = symbols('x y z w') A = Matrix([[ 1, 0, s13, 0 ], [ 0, 1, s23, 0 ], [ 0, 0, 1, 0 ], [ 0, 0, s43, 1 ]]) print('\nLacroute\'s shear matrix (A.14) is:') pprint.pprint(A) # At this point, we can write "print(A*p)". However, we don't care # about the output "z" axis, as it is fixed. So we delete the 3rd row # of A. A.row_del(2) p = Matrix([ x, y, z, 1 ]) v = A*p print('\nAction of Lacroute\'s shear matrix on plane z (taking w=1):\n%s\n' % v) print('Scaling = %s' % (1/v[2])) print('Offset X = %s' % (v[0]/v[2]).subs(x, 0)) print('Offset Y = %s' % (v[1]/v[2]).subs(y, 0))