data_augmentation function

[Yiyun Chen]

When I was runing the generatepatches.m, a error was raised that "undefined function or variable 'data_augmentation'.
I would like asking about it, is it a default function or user defined function that no provided?
thank you very much!

[Kai Zhang]

https://github.com/cszn/SRMD/blob/master/TrainingCodes/utilities/data_augmentation.m

[Yiyun Chen]

thank you!
and I am confused about the code:

for x = 1 : stride : (hei-size_input+1)
for y = 1 : stride : (wid-size_input+1)
x_l = stride_low*(x-1)/stride + 1;
y_l = stride_low*(y-1)/stride + 1;
if x_l+size_input/scale-1 > size(LR,1) || y_l+size_input/scale-1 > size(LR,2)
continue;
end
count=count+1;
end
end

in generatedpatches.
May I ask what this is trying to do.
Thank you.

[Kai Zhang]

In matlab, pre-define the large matrix is useful to the memery.

For example,

n = 1000000;
A = zeros(1, n); 
for i = 1:n
  A(i) = i; 
end

is better than

n = 1000000;
for i = 1:n
  A(i) = i; 
end

[Yiyun Chen]

Is it used to compute the 'count'?

[Kai Zhang]

Yes. @yiyunchen