speed up for and if loop

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Frederik Reese
Frederik Reese on 3 Aug 2022
Commented: Frederik Reese on 3 Aug 2022
Hi,
I want to get better in programming.
my Code works well but how can I speed up the calculation?
Thanks in andvance
for y=1:size(Wasserhoehe_HQ10000,1)%4585
for i= 1:10000% 2: size(FRI_10000_EventPhase,2);% 155
if isnan(Zeit_Flutende_10000_BA(y,:))==1
FRI_RecoveryPhase_10000(y,:)=nan;
else
if i == 1 % für ersten FRI Recovery letzten FRI Event als start
FRI_RecoveryPhase_10000(y,1)=FRI_10000_EventPhase(y,Zeit_Flutende_10000_BA(y,:)-1 ).*RF_10000(y,:);
else
FRI_RecoveryPhase_10000(y,[i])=FRI_RecoveryPhase_10000(y,i-1).*RF_10000(y,:); %4585X155
end
end
end
end
  4 Comments
Bruno Luong
Bruno Luong on 3 Aug 2022
"...that all elements of this row are NaN's or if any element is NaN?"
it's the same since
"Zeit_Flutende_10000_BA has only one column."

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Answers (1)

Jan
Jan on 3 Aug 2022
isnan replies trtue or false. There is no need to compare it with ==1 afterwards.
nWasserhoehe = size(Wasserhoehe_HQ, 1);
FRI_RecoveryPhase = zeros(nWasserhoehe, 10000); % Pre-allocation!!!
for y = 1:nWasserhoehe % 4585
RFy = RF(y, :); % Temporary variable
% für ersten FRI Recovery letzten FRI Event als start
FRI_RecoveryPhase(y, 1) = FRI_EventPhase(y, Zeit_Flutende_BA(y, :) - 1) .* RFy;
for i = 2:10000 % 2: size(FRI_EventPhase,2);% 155
if isnan(Zeit_Flutende_BA(y, :)) % any() or all() ?!?
FRI_RecoveryPhase(y, :) = nan;
else
FRI_RecoveryPhase(y, i) = FRI_RecoveryPhase(y, i - 1) .* RFy; %4585X155
end
end
end

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