Hi Forum,
Help! sympy.solve() always uses precision of 15 no matter what I try.
Recreated problem results:
In [*164*]: *import* *sympy*
In [*165*]: w,x,y,z=sympy.symbols('w,x,y,z')
In [*166*]: eqn=sympy.Eq(sympy.Float('1/55500',45)*w,sympy.Float('96500.0')*y)
In [*167*]: eqn.evalf(45)
Out[*167*]: Eq(0.000018018018018018018018018018018018018018018018*w,
96500.0*y)
In [*168*]: sympy.solve(eqn,y)[0].evalf(45)
Out[*168*]: 0.000000000186715212621948369903318027445619613213789734*w
In [*169*]: sympy.solve(eqn.evalf(45),y)[0].evalf(45)
Out[*169*]: 0.000000000186715212621948369903318027445619613213789734*w
The more accurate coefficient (to 45 digit accuracy) is:
In [*152*]: sympy.Float('1/55500',45)/sympy.Float('96500.0',45).evalf(45)
Out[*152*]: 0.000000000186715212621948373243710031274798114176352518
In [*174*]: sympy.Float('1',45)/sympy.Float('55500',45)/sympy.Float(
'96500.0',45).evalf(45)
Out[*174*]: 0.000000000186715212621948373243710031274798114176352518
So you see, the coefficient that results from sympy.solve:
0.000000000186715212621948369903318027445619613213789734
is accurate to only 15 digits of precision.
Clearly sympy.solve is using only 15 digit precision, even though I'm
specifying 45 digit precision.
How can I force sympy.solve to use 45 digit precision when it solves for y?
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