Hi,
I've got a (truncated) matrix over a power series ring over a finite field that I want to convert to a GP matrix so that I can take its kernel. Since the matrix is truncated, it can be viewed as just being over a univariate polynomial ring. I want to take its kernel, but the echelon form over a univariate polynomial ring over a finite field is not yet implemented. I knew GP can do this, so I was going to send the matrix to GP and have GP compute the kernel. But if I send the matrix as a matrix over the power series ring, the coefficients are not sent as being over a finite field. On the other hand, if I redefine the matrix over the polynomial ring, the coefficients are treated as being over a finite field. I could reconstruct all of my matrices as being over the polynomial ring once I truncate my series, but that seems like a silly hack -- GP understands power series rings over a finite field, so the conversion shouldn't be a problem. I'm running SAGE v3.0.2. Thanks, Salman Here is the code and output: sage: R.<x>=PowerSeriesRing(GF(5),"x") sage: m=matrix(R,2,[2+x, 1+x, 2+3*x,1+2*x]) sage: m.kernel() --------------------------------------------------------------------------- NotImplementedError Traceback (most recent call last) /Users/salmanhb/Documents/work/research/computations/sage/<ipython console> in <module>() /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.left_kernel (sage/matrix/matrix2.c:7985) () /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.echelon_form (sage/matrix/matrix2.c: 15292)() /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.echelonize (sage/matrix/matrix2.c:15092) () /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix._echelonize_ring (sage/matrix/matrix2.c: 14807)() NotImplementedError: echelon form over Power Series Ring in x over Finite Field of size 5 not yet implemented sage: gp(m) [x + 2, x + 1; 3*x + 2, 2*x + 1] sage: R.<x>=PolynomialRing(GF(5),"x") sage: m=matrix(R,2,[2+x, 1+x, 2+3*x,1+2*x]) sage: m.kernel() --------------------------------------------------------------------------- NotImplementedError Traceback (most recent call last) /Users/salmanhb/Documents/work/research/computations/sage/<ipython console> in <module>() /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.left_kernel (sage/matrix/matrix2.c:7985) () /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.echelon_form (sage/matrix/matrix2.c: 15292)() /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix.echelonize (sage/matrix/matrix2.c:15092) () /Users/salmanhb/Documents/work/research/computations/sage/matrix2.pyx in sage.matrix.matrix2.Matrix._echelonize_ring (sage/matrix/matrix2.c: 14807)() NotImplementedError: echelon form over Univariate Polynomial Ring in x over Finite Field of size 5 not yet implemented sage: gp(m) [Mod(1, 5)*x + Mod(2, 5), Mod(1, 5)*x + Mod(1, 5); Mod(3, 5)*x + Mod(2, 5), Mod(2, 5)*x + Mod(1, 5)] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
