GPULIB succes story (cont'd)

Regarding my last post, Peter Messmer at Tech-X pointed out to me that I should use gpuView rather than shifting subarrays around with gpuSubArr. Doesn't make things much faster in this case, but the code is nicer:

while i lt num_rows do begin
; ggi = GG[*,i*num_cols:(i+1)*num_cols-1]
gpuView,GG_gpu,i*num_cols*num_bands,$
num_bands*num_cols,ggi_gpu
gpuReform,ggi_gpu,num_bands,num_cols
; KK = transpose(G2)##(intarr(num_cols)+1)
gpuMatrix_Multiply,onesnc_gpu,G2_gpu,$
KK_gpu,/btranspose
; KK = KK + transpose(intarr(m)+1)##$
; GG2[i*num_cols:(i+1)*num_cols-1]
gpuView,GG2_gpu,i*num_cols,num_cols,gg2i_gpu
gpuMatrix_Multiply,gg2i_gpu,$
onesm_gpu,res_gpu,/btranspose
gpuAdd,KK_gpu,res_gpu,KK_gpu
; KK = KK - 2*G##transpose(ggi)
gpuMatrix_Multiply,ggi_gpu,G_gpu,$
res_gpu,/atranspose
gpuAdd,1.0,KK_gpu,-2.0,res_gpu,0.0,KK_gpu
; KK = exp(-gma*KK)
gpuExp,1.0,-gma,KK_gpu,0.0,0.0,KK_gpu
; image[*,i,*] = alpha[*,0:npc-1]##KK
gpuMatrix_Multiply,KK_gpu,alpha_gpu,res1_gpu
gpuGetArr,res1_gpu,res
image[*,i,*]=res
i++ ; next row
endwhile

With my new-found skills ;-) I want next to have a go at image clustering. If you cluster all of the pixel vectors in a multispectral image (typically millions) then things can get pretty slow.