hi again SR/GR students
In octave, if you define matrices and column vectors and "row one-forms" (called row vectors in octave), then operations you might find useful include:
1. http://en.wikipedia.org/wiki/Matrix_multiplication#Hadamard_product Hadamard product = entrywise product = Schur product
4-element column vectors A and B
A .* B gives you the Hadamard product = entrywise product = Schur product meaning another 4-element column vector
(Hadamard product also has a different meaning - see the Wikipedia section)
- similar for row vectors, matrices, etc.
2. sum(A)
For a 1D column vector or "row one-form", the meaning and syntax are obvious.
For a 2D matrix, you can add along rows or columns - but you probably don't need this for these tensor exercises.
3. work on or print a row or column of a matrix
example: the 2nd column of matrix g is
g(:,2)
example: the 3rd row of matrix g is
g(3,:)
4. get the inverse of matrix g
type
doc inverse
and read the documentation :).
pozdr boud
On Thu, 9 Jun 2011, Boud Roukema wrote:
hi SR/GR students,
Most of you are at KRA now, so i've opened up scoring for the exercises until 15.30. For people who cannot finish the exercises today, please propose another day e.g. next week. There is no point doing the exam if you have not passed (got at least 3 points) in the zaliczenia (there's probably also a formal UMK rule on this...)
For the exam, some people are thinking of
Tuesday 21.06.2011, from the 9.00 bus
but this is only a proposal, not yet definite.
pozdr boud
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