
Notunderstandable warning
Posted:
Apr 6, 2013 9:54 PM


Dear members:
I have a difficulty to understand programming in Mathematica.
I input the following, based on a textbook titled ``Programming with Mathematica: An Introduction" by Paul Wellin, which is published by Cambridge University Press.
mat = SparseArray[{i_, i_} \[RightArrow] 1, {4, 4}]
Then, I received an answer as SparseArray[{i_, i_} \[RightArrow] 1, {4, 4}]
with a warning as
`` SparseArray::list: "List expected at position 1 in SparseArray[{i_, i_} \[RightArrow] 1, {4, 4}]".
In this textbook, on page 32, there appears a correct answer as follows:
SparseArray[<4>, {4,4}].
Why my Mathematica cannot understand my input?
By the way, I use Mathematica 8.0.4.0 version and Mac OS 10.5.8.
Sincerely, Fujio Takata.

