Mojo function

im2col

im2col[dtype: DType](output: NDBuffer[dtype, 2, origin, shape, strides, alignment2=alignment2, address_space=address_space, exclusive=exclusive], activation: NDBuffer[dtype, 4, origin, shape, strides, alignment2=alignment2, address_space=address_space, exclusive=exclusive], problem: Conv2dProblemShape)

Explicit im2col transformation for convolution.

Transforms a 4D activation tensor [N, H, W, C] into a 2D matrix [M, K] for GEMM-based convolution.

M = batch * out_h * out_w K = in_channels * filter_h * filter_w

Note: This is a CPU reference implementation. For production use, the implicit im2col in the kernel is preferred.

Args:

output (NDBuffer): Output 2D buffer [M, K].
activation (NDBuffer): Input 4D buffer [N, H, W, C].
problem (Conv2dProblemShape): Convolution problem shape.