computing a distance matrix without using scipy python
0
I want to understand a specific part of code which computes a distance matrix between two 2d. matrices.
the smarter and easiest way to do it is by using scipy like this code
import scipy
import scipy.spatial
D = scipy.spatial.distance.cdist(X_norm, X_norm)
but there is an alternative way which i have a problem with to understand. It is this one
Dalt = np.sqrt(((X_norm ** 2).sum(axis=1).reshape((1, len(X_norm)))
+ (X_norm ** 2).sum(axis=1).reshape((len(X_norm), 1))
- 2 * numpy.dot(X_norm, X_norm.T)) + 1e-7)
print(((Dalt - D) ** 2).mean())
What I actually do not understand is the last part when he finally add this part
+ le-7)
python matrix matrix-multiplication scip
edited Nov 24 '18 at 14:01
desertnaut
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
add a comment |
0
I want to understand a specific part of code which computes a distance matrix between two 2d. matrices.
the smarter and easiest way to do it is by using scipy like this code
import scipy
import scipy.spatial
D = scipy.spatial.distance.cdist(X_norm, X_norm)
but there is an alternative way which i have a problem with to understand. It is this one
Dalt = np.sqrt(((X_norm ** 2).sum(axis=1).reshape((1, len(X_norm)))
+ (X_norm ** 2).sum(axis=1).reshape((len(X_norm), 1))
- 2 * numpy.dot(X_norm, X_norm.T)) + 1e-7)
print(((Dalt - D) ** 2).mean())
What I actually do not understand is the last part when he finally add this part
+ le-7)
python matrix matrix-multiplication scip
edited Nov 24 '18 at 14:01
desertnaut
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
1
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
@AhmedMohamed, that+ 1e-7actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case
– jtitusj
Nov 22 '18 at 18:22
1
Question has nothing to do withmachine-learningorartificial-intelligence- kindly do not spam the tags (removed).
– desertnaut
Nov 24 '18 at 14:02
add a comment |
0
0
0
I want to understand a specific part of code which computes a distance matrix between two 2d. matrices.
the smarter and easiest way to do it is by using scipy like this code
import scipy
import scipy.spatial
D = scipy.spatial.distance.cdist(X_norm, X_norm)
but there is an alternative way which i have a problem with to understand. It is this one
Dalt = np.sqrt(((X_norm ** 2).sum(axis=1).reshape((1, len(X_norm)))
+ (X_norm ** 2).sum(axis=1).reshape((len(X_norm), 1))
- 2 * numpy.dot(X_norm, X_norm.T)) + 1e-7)
print(((Dalt - D) ** 2).mean())
What I actually do not understand is the last part when he finally add this part
+ le-7)
python matrix matrix-multiplication scip
edited Nov 24 '18 at 14:01
desertnaut
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
I want to understand a specific part of code which computes a distance matrix between two 2d. matrices.
the smarter and easiest way to do it is by using scipy like this code
import scipy
import scipy.spatial
D = scipy.spatial.distance.cdist(X_norm, X_norm)
but there is an alternative way which i have a problem with to understand. It is this one
Dalt = np.sqrt(((X_norm ** 2).sum(axis=1).reshape((1, len(X_norm)))
+ (X_norm ** 2).sum(axis=1).reshape((len(X_norm), 1))
- 2 * numpy.dot(X_norm, X_norm.T)) + 1e-7)
print(((Dalt - D) ** 2).mean())
What I actually do not understand is the last part when he finally add this part
+ le-7)
python matrix matrix-multiplication scip
python matrix matrix-multiplication scip
edited Nov 24 '18 at 14:01
desertnaut
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
edited Nov 24 '18 at 14:01
desertnaut
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
edited Nov 24 '18 at 14:01
desertnaut
17k63668
edited Nov 24 '18 at 14:01
desertnaut
17k63668
edited Nov 24 '18 at 14:01
desertnaut
17k63668
17k63668
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
asked Nov 22 '18 at 16:40
Ahmed MohamedAhmed Mohamed
62
62
1
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
@AhmedMohamed, that+ 1e-7actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case
– jtitusj
Nov 22 '18 at 18:22
1
Question has nothing to do withmachine-learningorartificial-intelligence- kindly do not spam the tags (removed).
– desertnaut
Nov 24 '18 at 14:02
add a comment |
1
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
@AhmedMohamed, that+ 1e-7actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case
– jtitusj
Nov 22 '18 at 18:22
1
Question has nothing to do withmachine-learningorartificial-intelligence- kindly do not spam the tags (removed).
– desertnaut
Nov 24 '18 at 14:02
1
1
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
@AhmedMohamed, that
+ 1e-7 actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case– jtitusj
Nov 22 '18 at 18:22
@AhmedMohamed, that
+ 1e-7 actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case– jtitusj
Nov 22 '18 at 18:22
1
1
Question has nothing to do with
machine-learning or artificial-intelligence - kindly do not spam the tags (removed).– desertnaut
Nov 24 '18 at 14:02
Question has nothing to do with
machine-learning or artificial-intelligence - kindly do not spam the tags (removed).– desertnaut
Nov 24 '18 at 14:02
add a comment |
0
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1
Backslash is the way to continue the expression on the next line without having an indentation error
– Julien Rousé
Nov 22 '18 at 16:42
see stackoverflow.com/q/53162/3729797
– Julien Rousé
Nov 22 '18 at 16:44
Thankx alot for you comment
– Ahmed Mohamed
Nov 22 '18 at 17:03
@AhmedMohamed, that
+ 1e-7actually causes a small error and is not necessary. I'm not sure why the one who created that added that value. Usually, adding very small values is used to prevent computational errors however I could not identify the error they're trying to avoid in this case– jtitusj
Nov 22 '18 at 18:22
1
Question has nothing to do with
machine-learningorartificial-intelligence- kindly do not spam the tags (removed).– desertnaut
Nov 24 '18 at 14:02