matrix playing

Hi all

i have

w1 =

    1.0000    1.0000    1.0000    1.0000    1.0000    1.0000
    1.0000    1.0002    1.0000    1.0001    1.0000    1.0001

I want a new matrix with product of all terms in each 2x2 matrix in w1

Eventually, I need a 1x3 matrix.

If I use prod(w1), only the columns get multiplied.

Can anyone help please

Answer 1

[Walter Roberson]

blkproc(w1,[2 2],@prod)

[PChoppala]

w1 =

Columns 1 through 9

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.0001 1.0003 1.0001 1.0008 1.0002 1.0010 1.0002 1.0009 1.0019

Column 10

1.0000

1.0076

>> blkproc(w1, [2,2],@prod)

ans =

Columns 1 through 9

1.0001 1.0003 1.0001 1.0008 1.0002 1.0010 1.0002 1.0009 1.0019

Column 10

1.0076

this is what I get. All elements in each column are multiplied, I need,

if w1 = [a b c d ; e f g h]

w = [axexbxf cxgxdxh]

Can you help with this?

[Walter Roberson]

Ah...

blkproc(w1,[2 2],@(x) prod(x(:) )

[PChoppala]

Worked, but, just a quick question,

What is 'x'?

[Walter Roberson]

x is the "formal argument" for the anonymous function. It is nearly exactly like the x in

proc result = multiplyblock(x)

result = prod(x(:));

end

Answer 2

[Image Analyst]

Looks like a job for blockproc().

% Generate sample data.
w1 =[...
    1.0000    4.0000    1.0000    2.0000    1.0000    6.0000;
    1.0000    1.0002    1.0000    1.0001    1.0000    1.0001]

% Declare a function
  fun = @(block_struct) prod(block_struct.data(:)) 

% Do the job:
  result = blockproc(w1,[2 2], fun)

Note I changed w1 to make it easier to see that it actually did the job.

[PChoppala]

Worked!, many thanks mate!