You are correct. I wanted a way to perform the operation of linalg.solve for a matrix with dimensionality (x,y,z, b). If we use linalg.solve we would have to loop over voxels, which is what I am trying to avoid here. Does that even make sense though? 

Here - the rows will sometime be linearly dependent - in cases where measurements in two b values are done along the same direction. I haven't tested that yet, but that might be a problem (?).