How to improve the speed of of this function?

Good Morning, I am looking for some advice regarding improving the efficiency of my code. I have a simple loop I am running but it is the first time I am running it on the entirety of my data set and I now realize how slow my loop is. I am wondering if anyone might have some advice for improving the speed.

TRIAL1A_SPACE1 = zeros(size(T1A_raw_TEMP))
[r, c] = size(TRIAL1A_SPACE1)
for e = 1:r
    for f = 1:c
        if T1A_raw_TEMP(e,f) >= 8 && T1A_raw_HUM(e,f) >= 11
           TRIAL1A_SPACE1(e,f) = 1          
        end
    end
end

The [r,c] = [7824,183].

Thank you for any help or advice!

Answer 1

[Ingrid]

you do not need a loop for this, you can just use

TRIAL1A_SPACE1 = zeros(size(T1A_raw_TEMP));
TRIAL1A_SPACE1(T1A_raw_TEMP >= 8 && T1A_raw_HUM >= 11 ) = 1;

[Chameleon17]

Hi, thanks very much for your quick response.

I have tried using it without a loop but I get the error Operands to the and && operators must be convertible to logical scalar values.

I found another thread http://uk.mathworks.com/matlabcentral/newsreader/view_thread/169749 which seems to suggest the only way around this is a loop?

Answer 2

[Jos (10584)]

The command

TRIAL1A_SPACE1 = T1A_raw_TEMP >= 8 & T1A_raw_HUM >= 11

will make create the required (logical) matrix.

[Chameleon17]

Thank you very much for that! It worked!

I have another follow up question though, trying to get around loops that will take a very long time to execute.

TRIAL1A_SPACE3 = zeros(size(TRIAL1A_SPACE1)) [s, d] = size(TRIAL1A_SPACE3)

for g = 1:s for h = 1:d-1 if TRIAL1A_SPACE1(g,h) == 1 && TRIAL1A_SPACE1(g, h+1) == 1 TRIAL1A_SPACE3(g,h+1) = 1 end end end

is there a simpler way to complete the above, without looping, but I want to score for when an even has occurred for two consecutive days.

[Jos (10584)]

g = 1:s
h = 1:d-1
TRIAL1A_SPACE3(g,h+1) = TRIAL1A_SPACE1(g,h) == 1 & TRIAL1A_SPACE1(g, h+1) == 1