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Broadcasting & Slicing

Rules for operating on tensors of different shapes, and extracting sub-tensors.

Broadcasting​

When performing operations between tensors of different shapes, Morph automatically broadcasts the smaller tensor:

a is Tensor<float>.Random(3, 3);    // 3×3
b is Tensor<float>.Random(1, 3);    // 1×3

c is a + b;    // b is broadcast to 3×3

Rules​

  1. Dimensions are compared from right to left
  2. A dimension of size 1 is stretched to match the other
  3. Missing dimensions are treated as size 1

Slicing​

Extract sub-tensors using bracket notation:

data is Tensor<float>.Random(10, 10);
row is data[0];           // first row
slice is data[0..5];      // first 5 rows

Next Steps​

  • Neural Ops — Activation functions and BLAS operations