amp2sh dwi.mif - | sh2amp - sh2amp/dir20.txt - | testing_diff_image - sh2amp/out.mif -voxel 1e-5
amp2sh dwi.mif - | sh2amp - sh2amp/grad.txt -gradient - | testing_diff_image - sh2amp/out_grad.mif -voxel 1e-5
amp2sh dwi.mif - | sh2amp - sh2amp/dir20.txt -nonnegative - | testing_diff_image - sh2amp/out_nonneg.mif -voxel 1e-5
