/Python/Python matrix condensed to square

Python matrix condensed to square

def square_to_condensed(i, j, n):
    assert i != j, "no diagonal elements in condensed matrix"
    if i < j:
        i, j = j, i
    return n*j - j*(j+1)//2 + i - 1 - j

Source: stackoverflow.com

Python matrix condensed to square

>>> square_to_condensed(1, 2, len(points))
3
>>> dist_condensed[3]
4.4721359549995796
>>> dist[1,2]
4.4721359549995796

Source: stackoverflow.com

Python matrix condensed to square

import math

def calc_row_idx(k, n):
    return int(math.ceil((1/2.) * (- (-8*k + 4 *n**2 -4*n - 7)**0.5 + 2*n -1) - 1))

def elem_in_i_rows(i, n):
    return i * (n - 1 - i) + (i*(i + 1))//2

def calc_col_idx(k, i, n):
    return int(n - elem_in_i_rows(i + 1, n) + k)

def condensed_to_square(k, n):
    i = calc_row_idx(k, n)
    j = calc_col_idx(k, i, n)
    return i, j

Source: stackoverflow.com

Similar codes

4 votes331 views3 answers
How to create one list from 2d list python
Python
1 vote344 views1 answer
Gimp python
Python
5 votes345 views1 answer
Display np array as image
Python
0 vote318 views1 answer
Tkinter auto resize height
Python
0 vote369 views1 answer
Mad scipy
Python
1 vote334 views1 answer
Merge multiple csv files
Python
0 vote325 views1 answer
Clear cookies selenium python
Python
-1 vote313 views1 answer
If with && in python
Python
0 vote337 views1 answer
Python Split list into chunks using List Comprehension
Python
0 vote286 views10 answers
String float to round to 2dp python
Python