>> % Compute 7 factorial.
>> 7*6*5*4*3*2*1
ans =
5040
>> % Compute 7 factorial using a "for" loop.
>> n = 7;
>> nfact = 1;
>> for i=1:n,
nfact = nfact*i;
end;
>> nfact
nfact =
5040
>> % Compute 7 factorial using a "for" loop, going backwards.
>> nfact = 1;
>> for i=n:-1:1,
nfact = nfact*i;
end;
>> nfact
nfact =
5040
>> % Compute 7 factorial by running commands in the file fact.m.
>> fact
Enter n: 7
nfact =
5040
>> % Compute 10 factorial by running commands in the file fact.m.
>> fact
Enter n: 10
nfact =
3628800
>> % Compute 10 factorial using the function factorial (in file factorial.m).
>> factorial(10)
ans =
3628800
>> % Load a 2 by 2 matrix A with entries 1 and 2 in the first row,
>> % 3 and 4 in the second.
>> A = [1 2; 3 4]
A =
1 2
3 4
>> % Load a 2 by 2 matrix B with entries 5 and 6 in the first row,
>> % 7 and 8 in the second.
>> B = [5 6; 7 8]
B =
5 6
7 8
>> % Compute the product A*B.
>> A*B
ans =
19 22
43 50
>> % Load two random 10 by 10 matrices A and B.
>> A = randn(10,10); B = randn(10,10);
>> % Count the number of operations used to compute A*B.
>> flops(0) % This zeros the flop count.
>> A*B;
>> flops
ans =
2000
>> % Now load two random 20 by 20 matrices A and B.
>> A = randn(20,20); B = randn(20,20);
>> % Count the number of operations to compute A*B.
>> % Should be 8*2000=16000, since op count is O(n^3).
>> flops(0)
>> A*B;
>> flops
ans =
16000
>> % Eureka it worked! Signing off now...
>> exit
16000 flops.