Problem 42854. Crunch that matrix!

Solution 1233259

Submitted on 17 Jul 2017 by Justin Ng

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Test	Status	Code Input and Output
1	Pass	a=reshape(1:36,6,[]); b=[sum(a(:,1:3),2) sum(a(:,4:6),2)]; m=matrix_crunch(a); assert(max(max(abs(m-b)))<1e-10)
2	Pass	a=magic(9)-30; b=[sum(a(:,1:3),2) sum(a(:,4:6),2) sum(a(:,7:9),2)]; m=matrix_crunch(a); assert(max(max(abs(m-b)))<1e-10)
3	Pass	a=rand(12); b=[sum(a(:,1:3),2) sum(a(:,4:6),2) sum(a(:,7:9),2) sum(a(:,10:12),2)]; m=matrix_crunch(a); assert(max(max(abs(m-b)))<1e-10)
4	Pass	a=ones(18); b=3*ones(18,6); m=matrix_crunch(a); assert(max(max(abs(m-b)))<1e-10)
5	Pass	a=magic(15)+j.*flipud(magic(15)); a=a(1:10,:)-rand(10,15); b=[sum(a(:,1:3),2) sum(a(:,4:6),2) sum(a(:,7:9),2) sum(a(:,10:12),2) sum(a(:,13:15),2)]; m=matrix_crunch(a); assert(max(max(abs(m-b)))<1e-10)