Re: fast replace for matrix minor

*To*: mathgroup at smc.vnet.net*Subject*: [mg69507] Re: [mg69476] fast replace for matrix minor*From*: Sseziwa Mukasa <mukasa at jeol.com>*Date*: Thu, 14 Sep 2006 06:56:15 -0400 (EDT)*References*: <200609130803.EAA18423@smc.vnet.net>

On Sep 13, 2006, at 4:03 AM, Christopher Arthur wrote: > Is there a quick way to replace a small minor block in a large matrix? > Using ReplacePart in a Do loop seems to be very inefficient with > respect to timing If you are replacing a block just use part eg: In[188]:= Block[{mat={{a,b,c},{d,e,f},{g,h,i}}}, Print[mat];mat[[{2,3},{2,3}]]={{1,1},{1,1}};mat] From In[188]:= {{a,b,c},{d,e,f},{g,h,i}} Out[188]= {{a,b,c},{d,1,1},{g,1,1}} Regards, Ssezi

**References**:**fast replace for matrix minor***From:*Christopher Arthur <caa0012@unt.edu>