how can i give the 1 by 173 matrix as input to the k means clustering algorithm.

how can i give the 1 by 173 matrix as input to the k means clustering algorithm. is this code correct??? but am getting error as Index exceeds matrix dimension.

code clc X=load('D:\Viji\MATLAB\hist\e_dist.txt'); a=X(1,:); [idx,ctrs] = kmeans(a,3); plot(a(idx==1,1),'r.','MarkerSize',12); hold on plot(a(idx==2,1),'g.','MarkerSize',12); plot(a(idx==3,1),'b.','MarkerSize',12);

thank you.