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[Honza Stránský <_honzik@xxxxxxxxxx>]

Hello,

In Yade I work with two independent Matrix3 objects. Initially, they have all elements zeros, so I used Matrix3.Zero. But if I change an element in one matrix, it is changed in the other one as well.. here is an interactive session:

Yade [1]: a = Matrix3.Zero
Yade [2]: a
 ->  [2]: Matrix3(0,0,0, 0,0,0, 0,0,0)
Yade [3]: 
Yade [4]: b = Matrix3.Zero
Yade [5]: b
 ->  [5]: Matrix3(0,0,0, 0,0,0, 0,0,0)
Yade [6]: 
Yade [7]: a==b
 ->  [7]: True
Yade [8]: 
Yade [9]: a is b
 ->  [9]: False
Yade [10]: 
Yade [11]: a[0,1] = 2.
Yade [12]: 
Yade [13]: a
 ->  [13]: Matrix3(0,2,0, 0,0,0, 0,0,0)
Yade [14]: 
Yade [15]: b
 ->  [15]: Matrix3(0,2,0, 0,0,0, 0,0,0)
Yade [16]: 
Yade [17]: a == b
 ->  [17]: True
Yade [18]: 
Yade [19]: a is b
 ->  [19]: False


One possibility I found is not to use .Zero function:

Yade [1]: a = Matrix3()
Yade [2]: a
 ->  [2]: Matrix3(-1.49871e-63,-1.49737e-63,-1.49856e-63, -1.49841e-63,-1.49871e-63,-1.49852e-63, -1.49826e-63,-1.49826e-63,-1.49826e-63)
Yade [3]: 
Yade [4]: for i in range(3):
     ...:     for j in range(3):
     ...:         a[i,j] = 0.
     ...:         
     ...:         
Yade [5]: a
 ->  [5]: Matrix3(0,0,0, 0,0,0, 0,0,0)
Yade [6]: 
Yade [7]: b = Matrix3()
Yade [8]: b
 ->  [8]: Matrix3(7.84852e-314,1.9098e-313,7.46175e-308, -1.0674e-63,1.9034e-312,0, 2.96439e-323,1.71882e-312,0)
Yade [9]: for i in range(3):
    for j in range(3):
        b[i,j] = 0.
     ....:         
     ....:         
Yade [12]: b
 ->  [12]: Matrix3(0,0,0, 0,0,0, 0,0,0)
Yade [13]: 
Yade [14]: a[0,1] = 2.
Yade [15]: a
 ->  [15]: Matrix3(0,2,0, 0,0,0, 0,0,0)
Yade [16]: 
Yade [17]: b
 ->  [17]: Matrix3(0,0,0, 0,0,0, 0,0,0)


My question is, if there is some simplier procedure to achieve two independent Matrix3 objects with elements equal zero?

Thanks,

Jan