Hello there, I have a little kinematic project running.
I have a matrix with Denavit-Hartenberg parameters for each joint. See http://upload.wikimedia.org/math/6/e/3/6e3a9d7ad118c01e0e8b06cdc6d0205f.png In my case everything except theta is constant. I need to multiply this matrix with itself for each joint. To save some computing time I want to simplify the matrix. My matrix looks like this: dh = matrix([[cos(theta), sin(theta) * cos(x), sin(theta) * sin(x), r * cos(theta)], [sin(theta), cos(theta) * cos(x), -cos(theta) * sin(x), r * sin(theta)], [0, sin(x), cos(x), d], [0, 0, 0, 1]]) Where x is the variable for alpha. When I want to print the matrix for the second and following matrixes, maxima always crashes. Therefore I can't multiply and simplify the matrixes. Any suggestions?! Attached the traceback. File "simplification.py", line 90, in fk print dh File "matrix0.pyx", line 909, in sage.matrix.matrix0.Matrix.__repr__ (sage/matrix/matrix0.c:4766) File "matrix0.pyx", line 937, in sage.matrix.matrix0.Matrix.str (sage/matrix/matrix0.c:5075) File "matrix0.pyx", line 150, in sage.matrix.matrix0.Matrix.list (sage/matrix/matrix0.c:1787) File "matrix_symbolic_dense.pyx", line 328, in sage.matrix.matrix_symbolic_dense.Matrix_symbolic_dense._list (sage/ matrix/matrix_symbolic_dense.c:3043) File "matrix_symbolic_dense.pyx", line 123, in sage.matrix.matrix_symbolic_dense.Matrix_symbolic_dense.get_unsafe (sage/matrix/matrix_symbolic_dense.c:2165) File "/usr/lib/python2.5/site-packages/sage/calculus/calculus.py", line 8250, in symbolic_expression_from_maxima_string s = maxima._eval_line('_tmp_;') File "/usr/lib/python2.5/site-packages/sage/interfaces/maxima.py", line 566, in _eval_line self._expect_expr(self._display_prompt) File "/usr/lib/python2.5/site-packages/sage/interfaces/maxima.py", line 457, in _expect_expr i = self._expect.expect(expr) File "/usr/lib/python2.5/site-packages/pexpect.py", line 1311, in expect return self.expect_list(compiled_pattern_list, timeout, searchwindowsize) File "/usr/lib/python2.5/site-packages/pexpect.py", line 1325, in expect_list return self.expect_loop(searcher_re(pattern_list), timeout, searchwindowsize) File "/usr/lib/python2.5/site-packages/pexpect.py", line 1396, in expect_loop raise EOF (str(e) + '\n' + str(self)) pexpect.EOF: End Of File (EOF) in read_nonblocking(). Exception style platform. <pexpect.spawn object at 0xbc8060c> version: 2.3 ($Revision: 399 $) command: /usr/bin/maxima args: ['/usr/bin/maxima', '-p', '/usr/lib/sagemath/local/bin/sage- maxima.lisp'] searcher: searcher_re: 0: re.compile("<sage-display>") buffer (last 100 chars): before (last 100 chars): To reenable the Lisp debugger set *debugger- hook* to nil. (%i185) xmalloc: out of virtual memory after: <class 'pexpect.EOF'> match: None match_index: None exitstatus: None flag_eof: True pid: 3949 child_fd: 3 closed: False timeout: None delimiter: <class 'pexpect.EOF'> logfile: None logfile_read: None logfile_send: None maxread: 10000 ignorecase: False searchwindowsize: None delaybeforesend: 0 delayafterclose: 0.1 delayafterterminate: 0.1 -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
