The situation is as follows:
I have a 2D numpy array. Its shape is (1002, 1004). Each element contains a value between 0 and Inf. What I now want to do is determine the first 1000 maximum values and store the corresponding indices in to a list named x and a list named y. This is because I want to plot the maximum values and the indices actually correspond to real time x and y position of the value.
What I have so far is:
x = numpy.zeros(500)
y = numpy.zeros(500)
for idx in range(500):
x[idx] = numpy.unravel_index(full.argmax(), full.shape)[0]
y[idx] = numpy.unravel_index(full.argmax(), full.shape)[1]
full[full == full.max()] = 0.
print os.times()
Here full is my 2D numpy array. As can be seen from the for loop, I only determine the first 500 maximum values at the moment. This however already takes about 5 s. For the first 1000 maximum values, the user time should actually be around 0.5 s. I've noticed that a very time consuming part is setting the previous maximum value to 0 each time. How can I speed things up?
Thank you so much!