## Forum archive 2000-2006

### Thomas Hagedorn - Problem Typo

by Arnold Pizer -
Number of replies: 0
 Problem Typo topic started 9/9/2004; 6:11:32 PMlast post 9/13/2004; 1:00:10 PM
 Thomas Hagedorn - Problem Typo  9/9/2004; 6:11:32 PM (reads: 1034, responses: 2) We found a typo. In Problem setLinearAlgebra1Systems/ur_la_1_20.pg $j x_3 & needs to be replaced by$j x_5 &. As currently written, a x_3 shows up in the x_5 column. It should really be an x_5. -Tom <| Post or View Comments |>

 Arnold K. Pizer - Re: Problem Typo  9/10/2004; 1:44:56 PM (reads: 1295, responses: 0) Thanks Tom, The problem has been fixed and updated in the CVS. Arnie <| Post or View Comments |>

 Thomas Hagedorn - Re: Problem Typo  9/13/2004; 1:00:10 PM (reads: 1292, responses: 0) Arnie, Unfortunately, there seems to be a worse bug in the system with that problem. Again, its problem setLinearAlgebra1Systems/ur_la_1_20.pg If you use seed 4856, you'll get a problem with the variables chosen to be a=4, b=-2, c=4, d=-2, e=-3, f=-2, g=5, i=2, j=8, k=-6, l=-1 (in the problem's code). The solution should be (-1,0,1,-2,0,0) + s(-4,1,0,0,0,0) + t(-8,0,-2,-2,1,0) + u(6,0,2,5,0,1) If you enter that solution, you get credit. So far, so good. The problem is that the problem also evaluates the answer (-2,0,1,-2,0,0) + s(-4,1,0,0,0,0) + ... same as above as correct. But it isn't correct. In fact, it appears to me that changing any of the the first vectors's entries not corresponding to the free variables x_2, x_5, x_6 results in a correct answer. I looked at the code and it seems to me that the error must be occuring in the subroutine vec_solution_compare of the macro vec_solution_cmp. But I'm not proficient enought to have found the error. -Tom free <| Post or View Comments |>