How to Override a Calculated Value in a Matrix with an Assigned Value

Question

How do I override a calculated value within a matrix with an assigned value? Here is an example of what I mean. Consider matrix Y,

Y = MatrixForm[Table[i^j,{i, 0, 1, 0.5}, {j, 0, 2, 1}]]

with the output

Of course, the Indeterminate in Y[1, 1]is due to 0^0. How do I override the Indeterminate output with say Y[1, 1] = 1 while creating the matrix? Thank you.

Answer 1

In general, if you don't know in advance where Indeterminate entries are going to appear, you can use /. (ReplaceAll) to replace them with whatever you like. So

Y = Table[i^j, {i, 0, 1, 0.5}, {j, 0, 2, 1}];
(* {{Indeterminate, 0., 0.}, {1., 0.5, 0.25}, {1., 1., 1.}} *)

Then

Y /. {Indeterminate -> 1} 
(* {{1, 0., 0.}, {1., 0.5, 0.25}, {1., 1., 1.}} *)

Answer 2

FWIW, there is some undocumented functionality for generating Vandermonde matrices:

LinearAlgebra`VandermondeMatrix[{0, 0.5, 1}, Transpose -> True]
   {{1., 0., 0.}, {1., 0.5, 0.25}, {1., 1., 1.}}

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Edit 7/19/2022

In the current version, the following should be evaluated instead:

StructuredArray`VandermondeMatrix[{0, 0.5, 1}, List]

Answer 3

Also

Block[{Indeterminate = 1}, Quiet@Table[i^j, {i, 0, 1, 0.5}, {j, 0, 2, 1}]] 
   // MatrixForm // TeXForm

$\left( \begin{array}{ccc} 1 & 0. & 0. \\ 1. & 0.5 & 0.25 \\ 1. & 1. & 1. \\ \end{array} \right)$