How can I index a matrix in Theano by a vector of indices? More precisely, say that: <ul> <li> v has type theano.tensor.vector (e.g. [0,2]) </li> <li> A has type theano.tensor.matrix (e.g. [[1,0,0], [0,1,0], [0,0,1]])</li> </ul> The desired result is [[1,0,0], [0,0,1]]. I mention that my goal is to convert a list of indices into a matrix of one-hot row vectors, where the indices indicate the hot position. My initial attempt was to let A = theano.tensor.eye and index it using the vector of indices.

You can do: <pre class="prettyprint"><code>A[v] </code></pre> It will do what you want.

Indexing in Theano

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matrix-indexing

How can I index a matrix in Theano by a vector of indices?
More precisely, say that:

v has type theano.tensor.vector (e.g. [0,2])
A has type theano.tensor.matrix (e.g. [[1,0,0], [0,1,0], [0,0,1]])

The desired result is [[1,0,0], [0,0,1]].
I mention that my goal is to convert a list of indices into a matrix of one-hot row vectors, where the indices indicate the hot position. My initial attempt was to let A = theano.tensor.eye and index it using the vector of indices.