Le mercredi 7 novembre 2012 02:55:10 UTC+1, Steven D'Aprano a écrit : > > > > > > > Two-dimensional arrays in Python using lists are quite rare. Anyone who > > is doing serious numeric work where they need 2D arrays is using numpy, > > not lists. There are millions of people using Python, so it's hardly > > surprising that once or twice a year some newbie trips over this. But > > it's not something that people tend to trip over again and again and > > again, like C's "assignment is an expression" misfeature. > >
-------------------- >>> from vecmat6 import * >>> from vmio5 import * Traceback (most recent call last): File "<eta last command>", line 1, in <module> ImportError: No module named vmio5 >>> from vmio6 import * >>> from svdecomp6 import * >>> mm = NewMat(3, 3) >>> mm [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0], [0.0, 0.0, 0.0]] >>> mm[0][0] = 1.0; mm[0][1] = 2.0; mm[0][2] = 3.0 >>> mm[1][0] = 11.0; mm[1][1] = 12.0; mm[1][2] = 13.0 >>> mm[2][0] = 21.0; mm[2][1] = 22.0; mm[2][2] = 23.0 >>> pr(mm, 'mm=') mm= ( 1.00000e+000 2.00000e+000 3.00000e+000 ) ( 1.10000e+001 1.20000e+001 1.30000e+001 ) ( 2.10000e+001 2.20000e+001 2.30000e+001 ) >>> aa, b, cc = SVDecomp(mm) >>> pr(aa, 'aa=') aa= ( -8.08925e-002 -9.09280e-001 4.08248e-001 ) ( -4.77811e-001 -3.24083e-001 -8.16497e-001 ) ( -8.74730e-001 2.61114e-001 4.08248e-001 ) >>> pr(b, 'b=') b= ( 4.35902e+001 1.37646e+000 1.93953e-016 ) >>> pr(cc, 'cc=') cc= ( -5.43841e-001 7.33192e-001 4.08248e-001 ) ( -5.76726e-001 2.68499e-002 -8.16497e-001 ) ( -6.09610e-001 -6.79492e-001 4.08248e-001 ) >>> bb = VecToDiagMat(b) >>> cct = TransposeMat(cc) >>> oo = MatMulMatMulMat(aa, bb, cct) >>> pr(oo, 'aa * bb * cct=') aa * bb * cct= ( 1.00000e+000 2.00000e+000 3.00000e+000 ) ( 1.10000e+001 1.20000e+001 1.30000e+001 ) ( 2.10000e+001 2.20000e+001 2.30000e+001 ) >>> >>> # or >>> oo [[0.9999999999999991, 1.9999999999999993, 2.9999999999999982], [10.999999999999995, 11.99999999999999, 12.999999999999996], [20.999999999999986, 21.999999999999975, 22.999999999999986]] jmf -- http://mail.python.org/mailman/listinfo/python-list
