How does the bicubic interpolation downscales the image using imresize function ?

I want the theorotical explanation of the imresize function for downscaling the image. I have referred to the following

• https://blogs.mathworks.com/steve/2017/01/16/aliasing-and-image-resizing-part-3/
• https://blogs.mathworks.com/steve/2015/10/20/image-resizing-geometry/?s_tid=srchtitle
• The article "General Filtered Image Rescaling," by Dale Schumacher, in Graphics Gems III, Morgan Kaufmann, 1994.

I have understood how the indices are calculated in imresize function, but I am confused about how the weights are calculated in imresize function.

[KALYAN ACHARJYA]

Sir, have you looked here?

[Akshay Bhosale]

Thank you, I will go through it.

[Akshay Bhosale]

There is one hidden function named imresizemex, can you tell me what this function does ?