linalg:take-rows

(linalg:take-rows array indices)

Returns the axis-0 slices of array selected by the index vector indices (numpy's x[mask] / np.take(a, idx, axis=0)), as a fresh array of the input's width. Whole slabs are copied row-major, so any rank >= 1 works; index values are truncated to integers and the same index may appear more than once. With linalg:choice or linalg:permutation supplying the indices this is the mini-batch extraction idiom; the per-row element pick is linalg:gather. Axis 0 survives even for a single index (#(2) yields a (1 n) matrix, numpy's x[[2]]); to take one slice and drop the axis, use linalg:row.