How can i multiply every row to row values?

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Noman Abir
Noman Abir 2021-1-3
编辑： dpb 2021-1-5
I am looking for a way to multiply one row values with every row values.
Let's assume we have:
A=[1 2 3;
4 5 6;
7 8 9]
B=[a b c]
I am looking for a way to have:
C=[1*a 2*b 3*c;
4*a 5*b 6*c;
7*a 8*b 9*c]
Thanks in advance for your comments.

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dpb
dpb 2021-1-3
>> A=reshape(1:9,3,[])
A =
1.00 4.00 7.00
2.00 5.00 8.00
3.00 6.00 9.00
>> B=1:3;
>> A.*B
ans =
1.00 8.00 21.00
2.00 10.00 24.00
3.00 12.00 27.00
>>
Works after TMW implemented automagic vector expansion -- I don't recall which release but has been a few cycles now.
If the above doesn't work on your version, use bsxfun
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dpb
dpb 2021-1-5
That's what I just did above except for the full array -- the row of logical True shows every element matches to machine precision.
>> load y_send.mat
>> c1=ones(1,4);
>> demultiplex_data_y1=bsxfun(@times,c1,y_send);
>> all(y_send(:)==demultiplex_data_y1(:))
ans =
logical
1
>>
Explicitly using the variables instead...same result.
>> demultiplex_data_y1([1:5 end-5:end],:)
ans =
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
1.00 1.00 -1.00 3.00
-1.00 -1.00 -3.00 1.00
-1.00 -1.00 -3.00 1.00
-1.00 -1.00 -3.00 1.00
1.00 -3.00 -1.00 -1.00
1.00 -3.00 -1.00 -1.00
>> y_send([1:5 end-5:end],:)
ans =
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
-3.00 1.00 -1.00 -1.00
1.00 1.00 -1.00 3.00
-1.00 -1.00 -3.00 1.00
-1.00 -1.00 -3.00 1.00
-1.00 -1.00 -3.00 1.00
1.00 -3.00 -1.00 -1.00
1.00 -3.00 -1.00 -1.00
>>
First and last rows of both arrays -- identical as all() already told us.
Whatever you're looking at, bsxfun isn't the problem.
Or, if you can run the above test and show that
all(y_send(:)==demultiplex_data_y1(:))
returns anything other than a logical TRUE (1), then you have uncovered a bug in your release of MATLAB and should upgrade (which really should do, anyways).
dpb
dpb 2021-1-5
编辑：dpb 2021-1-5
Try the following modification to your program and see what happens there...
load('y_send.mat');
y_send;
bit = 4;
levels = 16;
Fs = 44100;
len = length(y_send);
t = 0:1/Fs:(len-1)/Fs;
max_x = 1;
min_x = -1;
step=(max_x-min_x)/levels;
c1 = [ 1 1 1 1 ];
%row to row and bit to bit multiplication of y_send and c1.
demultiplex_data_y1 = bsxfun(@times, c1, y_send);
demultiplex_data_y1;
if any(demultiplex_data_y1(:)~=y_send(:))
disp('ERROR! bsxfun() times failure with unity multiplier')
else
disp('SUCCESS! bsxfun() times with unity multiplier returns original')
end
...
Running it here resulted in
>> receive_cdm
SUCCESS! bsxfun() times with unity multiplier returns original
>>

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