Created Sherman Morrison method#1162
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cclauss
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This is really slick! I like the type hints and assertions to guard against bad data. Nice contribution.
A couple of optional things that I would be interested to see added are doctests and list comprehensions.
1. Added docstring tests 2. Tweaked __str__() using join 3. Added __repr__() 4. Changed index validation to be independent method
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@cclauss I added doctests. By the way, I'm sorry, what do you mean for list comprehension? Do you want some method to iterate over all elements in matrix as single 1x1 element or row/column vector? |
| s += "[" | ||
| s += ", ".join(string_format_identifier % (obj,) for obj in row_vector) | ||
| s += "]\n" | ||
| s += "\n".join("[" + ", ".join(string_format_identifier % (obj,) for obj in row_vector) + "]" for row_vector in self.array) |
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This line can not be read on GitHub without left-right scrolling. Please wrap it so this is no longer the case.
| # Validation | ||
| assert(self.row == another.row and self.column == another.column) | ||
| assert(isinstance(another, Matrix)) | ||
| assert(self.row == another.row and self.column == another.column) |
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assert(0)
assert(False)
Lose the parens ()... it is not a function.
1. Reduced line length for __str__() 2. Removed parens for assert
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If you need more things to fix then please write comments. Thank you. |
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@cclauss Is there anything needed to change? |
* Created Sherman Morrison * Added docstring for class * Updated Sherman morrison 1. Added docstring tests 2. Tweaked __str__() using join 3. Added __repr__() 4. Changed index validation to be independent method * Applied cclauss's point 1. Reduced line length for __str__() 2. Removed parens for assert
I created method to apply Sherman-Morrison formula to Matrix.
Sherman-Morrison formula is important to reduce time complexity on calculating inverse matrix on some special cases. This formula is also used to improve BFGS update performance. For deeper stuffs please look into this documents:
https://en.wikipedia.org/wiki/Sherman%E2%80%93Morrison_formula
https://en.wikipedia.org/wiki/Broyden%E2%80%93Fletcher%E2%80%93Goldfarb%E2%80%93Shanno_algorithm
https://en.wikipedia.org/wiki/Quasi-Newton_method