cxrjdd's profile - activity

Thank you very much.

The complex multiplication of matrix changes the base ring.

A = matrix(CDF,[[1,2],[3,4]]); print(A)
B = 2*A
C = I*A
print(type(A))
print(type(B))
print(type(C))

The result is

[1.0 2.0]
[3.0 4.0]
<class 'sage.matrix.matrix_complex_double_dense.Matrix_complex_double_dense'>
<class 'sage.matrix.matrix_complex_double_dense.Matrix_complex_double_dense'>
<class 'sage.matrix.matrix_symbolic_dense.Matrix_symbolic_dense'>

So the multiplication by an imaginary number breaks the CDF property. This is very inconvenient for numerical calculations, because the symbolic computation is very slow.

Thank you for telling me the correct usage.

The special value of the hypergeometric 2F1 can be found in http://mathworld.wolfram.com/HypergeometricFunction.html (this page) or maybe its reference. By the way, 8/6 in my posting is typo.　Correctly, this is 8/5.

I want to compute the value of hypergeometric 2F1 like this.

a=1/3; b=2/3; c=5/6; x=27/32
print n(hypergeometric([2,1],[a,b,c],x))

Sage math answered 16.9608452387059. But this should be 8.0/5=1.6000000.

I want to compute the value of hypergeometric 2F1 like this

a=1/3; b=2/3; c=5/6; x=27/32
print n(hypergeometric([2,1],[a,b,c],x)

Sagemath answered 16.9608452387059. But this should be 8/5=1.60000000. All the other numerical values are also unreliable.

I hope this will be fixed in the next version.