Stefan Krah <skrah at bytereef.org>
The gumath.functions module wraps the builtin libgumath kernels and serves as an example of a modular namespace.
>>> from gumath import functions as fn >>> dir(fn) ['__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'abs', 'acos', 'acosh', 'add', 'asin', 'asinh', 'atan', 'atanh', 'bitwise_and', 'bitwise_or', 'bitwise_xor', 'cbrt', 'ceil', 'copy', 'cos', 'cosh', 'divide', 'divmod', 'equal', 'equaln', 'erf', 'erfc', 'exp', 'exp2', 'expm1', 'fabs', 'floor', 'floor_divide', 'greater', 'greater_equal', 'invert', 'less', 'less_equal', 'lgamma', 'log', 'log10', 'log1p', 'log2', 'logb', 'multiply', 'nearbyint', 'negative', 'not_equal', 'power', 'remainder', 'round', 'sin', 'sinh', 'sqrt', 'subtract', 'tan', 'tanh', 'tgamma', 'trunc']
>>> from xnd import xnd >>> x = xnd([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]]) >>> fn.log(x) xnd([[0.0, 0.6931471805599453, 1.0986122886681098], [1.3862943611198906, 1.6094379124341003, 1.791759469228055]], type='2 * 3 * float64')
On an array with a float64 dtype, log works as expected.
>>> x = xnd([[1, 2, 3], [4, 5, 6]]) >>> x.type ndt("2 * 3 * int64") >>> fn.log(x) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: invalid dtype
This function call would require an implicit inexact conversion from int64 to float64. All builtin libgumath kernels only allow exact conversions, so the example fails.
>>> x = xnd([[1, 2, 3], [4, 5, 6]], dtype="int32") >>> fn.log(x) xnd([[0.0, 0.6931471805599453, 1.0986122886681098], [1.3862943611198906, 1.6094379124341003, 1.791759469228055]], type='2 * 3 * float64')
int32 to float64 conversions are exact, so the call succeeds.