Previous Up Next

5.8.1  Transform a floating point number into a rational: exact float2rational

float2rational or exact takes as argument a floating point number d and returns a rational number q close to d such that abs(d-q)<epsilon. epsilon is defined in the cas configuration (Cfg menu) or with the cas_setup command.
Input:

float2rational(0.3670520231)

Output when epsilon=1e-10:

127/346

Input:

evalf(363/28)

Output:

12.9642857143

Input:

float2rational(12.9642857143)

Output:

363/28

If two representations are mixed, for example:

1/2+0.7

the rational is converted to a float, output:

1.2

Input:

1/2+float2rational(0.7)

Output:

6/5

Previous Up Next